summaryrefslogtreecommitdiff
path: root/docs/hooks.txt
blob: 7671e6e3f56679168136dcb016fd4aedf1184fe5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
hooks.txt

This document describes how event hooks work in MediaWiki; how to add hooks for
an event; and how to run hooks for an event.

==Glossary==

event
     Something that happens with the wiki. For example: a user logs in. A wiki
     page is saved. A wiki page is deleted. Often there are two events
     associated with a single action: one before the code is run to make the
     event happen, and one after. Each event has a name, preferably in
     CamelCase. For example, 'UserLogin', 'ArticleSave', 'ArticleSaveComplete',
     'ArticleDelete'.

hook
     A clump of code and data that should be run when an event happens. This can
     be either a function and a chunk of data, or an object and a method.

hook function
     The function part of a hook.

==Rationale==

Hooks allow us to decouple optionally-run code from code that is run for
everyone. It allows MediaWiki hackers, third-party developers and local
administrators to define code that will be run at certain points in the mainline
code, and to modify the data run by that mainline code. Hooks can keep mainline
code simple, and make it easier to write extensions. Hooks are a principled
alternative to local patches.

Consider, for example, two options in MediaWiki. One reverses the order of a
title before displaying the article; the other converts the title to all
uppercase letters. Currently, in MediaWiki code, we would handle this as follows
(note: not real code, here):

	function showAnArticle( $article ) {
		global $wgReverseTitle, $wgCapitalizeTitle;

		if ( $wgReverseTitle ) {
			wfReverseTitle( $article );
		}

		if ( $wgCapitalizeTitle ) {
			wfCapitalizeTitle( $article );
		}

		# code to actually show the article goes here
	}

An extension writer, or a local admin, will often add custom code to the
function -- with or without a global variable. For example, someone wanting
email notification when an article is shown may add:

	function showAnArticle( $article ) {
		global $wgReverseTitle, $wgCapitalizeTitle, $wgNotifyArticle;

		if ( $wgReverseTitle ) {
			wfReverseTitle( $article );
		}

		if ( $wgCapitalizeTitle ) {
			wfCapitalizeTitle( $article );
		}

		# code to actually show the article goes here

		if ( $wgNotifyArticle ) {
			wfNotifyArticleShow( $article );
		}
	}

Using a hook-running strategy, we can avoid having all this option-specific
stuff in our mainline code. Using hooks, the function becomes:

	function showAnArticle( $article ) {

		if ( Hooks::run( 'ArticleShow', array( &$article ) ) ) {

			# code to actually show the article goes here

			Hooks::run( 'ArticleShowComplete', array( &$article ) );
		}
	}

We've cleaned up the code here by removing clumps of weird, infrequently used
code and moving them off somewhere else. It's much easier for someone working
with this code to see what's _really_ going on, and make changes or fix bugs.

In addition, we can take all the code that deals with the little-used
title-reversing options (say) and put it in one place. Instead of having little
title-reversing if-blocks spread all over the codebase in showAnArticle,
deleteAnArticle, exportArticle, etc., we can concentrate it all in an extension
file:

	function reverseArticleTitle( $article ) {
		# ...
	}

	function reverseForExport( $article ) {
		# ...
	}

The setup function for the extension just has to add its hook functions to the
appropriate events:

	setupTitleReversingExtension() {
		global $wgHooks;

		$wgHooks['ArticleShow'][] = 'reverseArticleTitle';
		$wgHooks['ArticleDelete'][] = 'reverseArticleTitle';
		$wgHooks['ArticleExport'][] = 'reverseForExport';
	}

Having all this code related to the title-reversion option in one place means
that it's easier to read and understand; you don't have to do a grep-find to see
where the $wgReverseTitle variable is used, say.

If the code is well enough isolated, it can even be excluded when not used --
making for some slight savings in memory and load-up performance at runtime.
Admins who want to have all the reversed titles can add:

	require_once 'extensions/ReverseTitle.php';

...to their LocalSettings.php file; those of us who don't want or need it can
just leave it out.

The extensions don't even have to be shipped with MediaWiki; they could be
provided by a third-party developer or written by the admin him/herself.

==Writing hooks==

A hook is a chunk of code run at some particular event. It consists of:

  * a function with some optional accompanying data, or
  * an object with a method and some optional accompanying data.

Hooks are registered by adding them to the global $wgHooks array for a given
event. All the following are valid ways to define hooks:

	$wgHooks['EventName'][] = 'someFunction'; # function, no data
	$wgHooks['EventName'][] = array( 'someFunction', $someData );
	$wgHooks['EventName'][] = array( 'someFunction' ); # weird, but OK

	$wgHooks['EventName'][] = $object; # object only
	$wgHooks['EventName'][] = array( $object, 'someMethod' );
	$wgHooks['EventName'][] = array( $object, 'someMethod', $someData );
	$wgHooks['EventName'][] = array( $object ); # weird but OK

When an event occurs, the function (or object method) will be called with the
optional data provided as well as event-specific parameters. The above examples
would result in the following code being executed when 'EventName' happened:

	# function, no data
	someFunction( $param1, $param2 )
	# function with data
	someFunction( $someData, $param1, $param2 )

	# object only
	$object->onEventName( $param1, $param2 )
	# object with method
	$object->someMethod( $param1, $param2 )
	# object with method and data
	$object->someMethod( $someData, $param1, $param2 )

Note that when an object is the hook, and there's no specified method, the
default method called is 'onEventName'. For different events this would be
different: 'onArticleSave', 'onUserLogin', etc.

The extra data is useful if we want to use the same function or object for
different purposes. For example:

	$wgHooks['ArticleSaveComplete'][] = array( 'ircNotify', 'TimStarling' );
	$wgHooks['ArticleSaveComplete'][] = array( 'ircNotify', 'brion' );

This code would result in ircNotify being run twice when an article is saved:
once for 'TimStarling', and once for 'brion'.

Hooks can return three possible values:

  * true: the hook has operated successfully
  * "some string": an error occurred; processing should stop and the error
                   should be shown to the user
  * false: the hook has successfully done the work necessary and the calling
           function should skip

The last result would be for cases where the hook function replaces the main
functionality. For example, if you wanted to authenticate users to a custom
system (LDAP, another PHP program, whatever), you could do:

	$wgHooks['UserLogin'][] = array( 'ldapLogin', $ldapServer );

	function ldapLogin( $username, $password ) {
		# log user into LDAP
		return false;
	}

Returning false makes less sense for events where the action is complete, and
will normally be ignored.

Note that none of the examples made use of create_function() as a way to
attach a function to a hook. This is known to cause problems (notably with
Special:Version), and should be avoided when at all possible.

==Using hooks==

A calling function or method uses the Hooks::run() function to run the hooks
related to a particular event, like so:

	class Article {
		# ...
		function protect() {
			global $wgUser;
			if ( Hooks::run( 'ArticleProtect', array( &$this, &$wgUser ) ) ) {
				# protect the article
				Hooks::run( 'ArticleProtectComplete', array( &$this, &$wgUser ) );
			}
		}
	}

Hooks::run() returns true if the calling function should continue processing
(the hooks ran OK, or there are no hooks to run), or false if it shouldn't (an
error occurred, or one of the hooks handled the action already). Checking the
return value matters more for "before" hooks than for "complete" hooks.

Hooks::run() was added in MediaWiki 1.18, before that the global function
wfRunHooks must be used, which was deprecated in MediaWiki 1.25.

Note that hook parameters are passed in an array; this is a necessary
inconvenience to make it possible to pass reference values (that can be changed)
into the hook code. Also note that earlier versions of wfRunHooks took a
variable number of arguments; the array() calling protocol came about after
MediaWiki 1.4rc1.

==Events and parameters==

This is a list of known events and parameters; please add to it if you're going
to add events to the MediaWiki code.

'AbortAutoAccount': Return false to cancel automated local account creation,
where normally authentication against an external auth plugin would be creating
a local account.
$user: the User object about to be created (read-only, incomplete)
&$abortMsg: out parameter: name of error message to be displayed to user

'AbortAutoblock': Return false to cancel an autoblock.
$autoblockip: The IP going to be autoblocked.
$block: The block from which the autoblock is coming.

'AbortChangePassword': Return false to cancel password change.
$user: the User object to which the password change is occuring
$mOldpass: the old password provided by the user
$newpass: the new password provided by the user
&$abortMsg: the message identifier for abort reason

'AbortDiffCache': Can be used to cancel the caching of a diff.
&$diffEngine: DifferenceEngine object

'AbortEmailNotification': Can be used to cancel email notifications for an edit.
$editor: The User who made the change.
$title: The Title of the page that was edited.
$rc: The current RecentChange object.

'AbortLogin': Return false to cancel account login.
$user: the User object being authenticated against
$password: the password being submitted, not yet checked for validity
&$retval: a LoginForm class constant to return from authenticateUserData();
  default is LoginForm::ABORTED. Note that the client may be using a machine
  API rather than the HTML user interface.
&$msg: the message identifier for abort reason (new in 1.18, not available
  before 1.18)

'AbortNewAccount': Return false to cancel explicit account creation.
$user: the User object about to be created (read-only, incomplete)
&$msg: out parameter: HTML to display on abort
&$status: out parameter: Status object to return, replaces the older $msg param
  (added in 1.23)
  Create the object with Status::newFatal() to ensure proper API error
  messages are returned when creating account through API clients.

'AbortTalkPageEmailNotification': Return false to cancel talk page email
notification
$targetUser: the user whom to send talk page email notification
$title: the page title

'ActionBeforeFormDisplay': Before executing the HTMLForm object.
$name: name of the action
&$form: HTMLForm object
$article: Article object

'ActionModifyFormFields': Before creating an HTMLForm object for a page action;
Allows to change the fields on the form that will be generated.
$name: name of the action
&$fields: HTMLForm descriptor array
$article: Article object

'AddNewAccount': After a user account is created.
$user: the User object that was created. (Parameter added in 1.7)
$byEmail: true when account was created "by email" (added in 1.12)

'AddNewAccountApiForm': Allow modifying internal login form when creating an
account via API.
$apiModule: the ApiCreateAccount module calling
$loginForm: the LoginForm used

'AddNewAccountApiResult': Modify API output when creating a new account via API.
$apiModule: the ApiCreateAccount module calling
$loginForm: the LoginForm used
&$result: associative array for API result data

'AfterFinalPageOutput': Nearly at the end of OutputPage::output() but
before OutputPage::sendCacheControl() and final ob_end_flush() which
will send the buffered output to the client. This allows for last-minute
modification of the output within the buffer by using ob_get_clean().
$output: The OutputPage object where output() was called

'AfterImportPage': When a page import is completed.
$title: Title under which the revisions were imported
$foreignTitle: ForeignTitle object based on data provided by the XML file
$revCount: Number of revisions in the XML file
$sRevCount: Number of successfully imported revisions
$pageInfo: associative array of page information

'AfterParserFetchFileAndTitle': After an image gallery is formed by Parser,
just before adding its HTML to parser output.
$parser: Parser object that called the hook
$ig: Gallery, an object of one of the gallery classes (inheriting from
  ImageGalleryBase)
$html: HTML generated by the gallery

'AlternateEdit': Before checking if a user can edit a page and before showing
the edit form ( EditPage::edit() ). This is triggered on &action=edit.
$editPage: the EditPage object

'AlternateEditPreview': Before generating the preview of the page when editing
( EditPage::getPreviewText() ).
Return false and set $previewHTML and $parserOutput to output custom page
preview HTML.
$editPage: the EditPage object
&$content: the Content object for the text field from the edit page
&$previewHTML: Text to be placed into the page for the preview
&$parserOutput: the ParserOutput object for the preview

'AlternateUserMailer': Called before mail is sent so that mail could be logged
(or something else) instead of using PEAR or PHP's mail(). Return false to skip
the regular method of sending mail.  Return a string to return a php-mail-error
message containing the error. Returning true will continue with sending email
in the regular way.
$headers: Associative array of headers for the email
$to: MailAddress object or array
$from: From address
$subject: Subject of the email
$body: Body of the message

'APIAfterExecute': After calling the execute() method of an API module. Use
this to extend core API modules.
&$module: Module object

'ApiBeforeMain': Before calling ApiMain's execute() method in api.php.
&$main: ApiMain object

'ApiCheckCanExecute': Called during ApiMain::checkCanExecute. Use to further
authenticate and authorize API clients before executing the module. Return
false and set a message to cancel the request.
$module: Module object
$user: Current user
&$message: API usage message to die with, as a message key or array
  as accepted by ApiBase::dieUsageMsg.

'APIEditBeforeSave': Before saving a page with api.php?action=edit, after
processing request parameters. Return false to let the request fail, returning
an error message or an <edit result="Failure"> tag if $resultArr was filled.
$editPage: the EditPage object
$text: the new text of the article (has yet to be saved)
&$resultArr: data in this array will be added to the API result

'ApiFeedContributions::feedItem': Called to convert the result of ContribsPager
into a FeedItem instance that ApiFeedContributions can consume. Implementors of
this hook may cancel the hook to signal that the item is not viewable in the
provided context.
$row: A row of data from ContribsPager.  The set of data returned by
  ContribsPager can be adjusted by handling the ContribsPager::reallyDoQuery
  hook.
$context: An IContextSource implementation.
&$feedItem: Set this to a FeedItem instance if the callback can handle the
  provided row. This is provided to the hook as a null, if it is non null then
  another callback has already handled the hook.

'ApiFormatHighlight': Use to syntax-highlight API pretty-printed output. When
highlighting, add output to $context->getOutput() and return false.
$context: An IContextSource.
$text: Text to be highlighted.
$mime: MIME type of $text.
$format: API format code for $text.

'APIGetAllowedParams': Use this hook to modify a module's parameters.
&$module: ApiBase Module object
&$params: Array of parameters
$flags: int zero or OR-ed flags like ApiBase::GET_VALUES_FOR_HELP

'APIGetDescription': DEPRECATED! Use APIGetDescriptionMessages instead.
Use this hook to modify a module's description.
&$module: ApiBase Module object
&$desc: String description, or array of description strings

'APIGetDescriptionMessages': Use this hook to modify a module's help message.
$module: ApiBase Module object
&$msg: Array of Message objects

'APIGetParamDescription': DEPRECATED! Use APIGetParamDescriptionMessages
instead.
Use this hook to modify a module's parameter descriptions.
&$module: ApiBase Module object
&$desc: Array of parameter descriptions

'APIGetParamDescriptionMessages': Use this hook to modify a module's parameter
descriptions.
$module: ApiBase Module object
&$msg: Array of arrays of Message objects

'APIHelpModifyOutput': Use this hook to modify an API module's help output.
$module: ApiBase Module object
&$help: Array of HTML strings to be joined for the output.
$options: Array Options passed to ApiHelp::getHelp
&$tocData: Array If a TOC is being generated, this array has keys as anchors in
  the page and values as for Linker::generateTOC().

'ApiMain::moduleManager': Called when ApiMain has finished initializing its
module manager. Can be used to conditionally register API modules.
$moduleManager: ApiModuleManager Module manager instance

'ApiMain::onException': Called by ApiMain::executeActionWithErrorHandling() when
an exception is thrown during API action execution.
$apiMain: Calling ApiMain instance.
$e: Exception object.

'ApiOpenSearchSuggest': Called when constructing the OpenSearch results. Hooks
can alter or append to the array.
&$results: array with integer keys to associative arrays. Keys in associative
  array:
    - title: Title object.
    - redirect from: Title or null.
    - extract: Description for this result.
    - extract trimmed: If truthy, the extract will not be trimmed to
      $wgOpenSearchDescriptionLength.
    - image: Thumbnail for this result. Value is an array with subkeys 'source'
      (url), 'width', 'height', 'alt', 'align'.
    - url: Url for the given title.

'ApiQuery::moduleManager': Called when ApiQuery has finished initializing its
module manager. Can be used to conditionally register API query modules.
$moduleManager: ApiModuleManager Module manager instance

'APIQueryAfterExecute': After calling the execute() method of an
action=query submodule. Use this to extend core API modules.
&$module: Module object

'APIQueryGeneratorAfterExecute': After calling the executeGenerator() method of
an action=query submodule. Use this to extend core API modules.
&$module: Module object
&$resultPageSet: ApiPageSet object

'APIQueryInfoTokens': DEPRECATED! Use ApiQueryTokensRegisterTypes instead.
Use this hook to add custom tokens to prop=info. Every token has an action,
which will be used in the intoken parameter and in the output
(actiontoken="..."), and a callback function which should return the token, or
false if the user isn't allowed to obtain it. The prototype of the callback
function is func($pageid, $title), where $pageid is the page ID of the page the
token is requested for and $title is the associated Title object. In the hook,
just add your callback to the $tokenFunctions array and return true (returning
false makes no sense).
$tokenFunctions: array(action => callback)

'APIQueryRecentChangesTokens': DEPRECATED! Use ApiQueryTokensRegisterTypes
instead.
Use this hook to add custom tokens to list=recentchanges. Every token has an
action, which will be used in the rctoken parameter and in the output
(actiontoken="..."), and a callback function which should return the token, or
false if the user isn't allowed to obtain it. The prototype of the callback
function is func($pageid, $title, $rc), where $pageid is the page ID of the
page associated to the revision the token is requested for, $title the
associated Title object and $rc the associated RecentChange object. In the
hook, just add your callback to the $tokenFunctions array and return true
(returning false makes no sense).
$tokenFunctions: array(action => callback)

'APIQueryRevisionsTokens': DEPRECATED! Use ApiQueryTokensRegisterTypes instead.
Use this hook to add custom tokens to prop=revisions. Every token has an
action, which will be used in the rvtoken parameter and in the output
(actiontoken="..."), and a callback function which should return the token, or
false if the user isn't allowed to obtain it. The prototype of the callback
function is func($pageid, $title, $rev), where $pageid is the page ID of the
page associated to the revision the token is requested for, $title the
associated Title object and $rev the associated Revision object. In the hook,
just add your callback to the $tokenFunctions array and return true (returning
false makes no sense).
$tokenFunctions: array(action => callback)

'APIQuerySiteInfoGeneralInfo': Use this hook to add extra information to the
sites general information.
$module: the current ApiQuerySiteInfo module
&$results: array of results, add things here

'APIQuerySiteInfoStatisticsInfo': Use this hook to add extra information to the
sites statistics information.
&$results: array of results, add things here

'ApiQueryTokensRegisterTypes': Use this hook to add additional token types to
action=query&meta=tokens. Note that most modules will probably be able to use
the 'csrf' token instead of creating their own token types.
&$salts: array( type => salt to pass to User::getEditToken() )

'APIQueryUsersTokens': DEPRECATED! Use ApiQueryTokensRegisterTypes instead.
Use this hook to add custom token to list=users. Every token has an action,
which will be used in the ustoken parameter and in the output
(actiontoken="..."), and a callback function which should return the token, or
false if the user isn't allowed to obtain it. The prototype of the callback
function is func($user) where $user is the User object. In the hook, just add
your callback to the $tokenFunctions array and return true (returning false
makes no sense).
$tokenFunctions: array(action => callback)

'ApiRsdServiceApis': Add or remove APIs from the RSD services list. Each service
should have its own entry in the $apis array and have a unique name, passed as
key for the array that represents the service data. In this data array, the
key-value-pair identified by the apiLink key is required.
&$apis: array of services

'ApiTokensGetTokenTypes': DEPRECATED! Use ApiQueryTokensRegisterTypes instead.
Use this hook to extend action=tokens with new token types.
&$tokenTypes: supported token types in format 'type' => callback function
  used to retrieve this type of tokens.

'Article::MissingArticleConditions': Before fetching deletion & move log entries
to display a message of a non-existing page being deleted/moved, give extensions
a chance to hide their (unrelated) log entries.
&$conds: Array of query conditions (all of which have to be met; conditions will
  AND in the final query)
$logTypes: Array of log types being queried

'ArticleAfterFetchContent': DEPRECATED! Use ArticleAfterFetchContentObject
instead.
After fetching content of an article from the database.
$article: the article (object) being loaded from the database
&$content: the content (string) of the article

'ArticleAfterFetchContentObject': After fetching content of an article from the
database.
$article: the article (object) being loaded from the database
&$content: the content of the article, as a Content object

'ArticleConfirmDelete': Before writing the confirmation form for article
deletion.
$article: the article (object) being deleted
$output: the OutputPage object
&$reason: the reason (string) the article is being deleted

'ArticleContentOnDiff': Before showing the article content below a diff. Use
this to change the content in this area or how it is loaded.
$diffEngine: the DifferenceEngine
$output: the OutputPage object

'ArticleContentViewCustom': Allows to output the text of the article in a
different format than wikitext. Note that it is preferable to implement proper
handing for a custom data type using the ContentHandler facility.
$content: content of the page, as a Content object
$title: title of the page
$output: reference to $wgOut

'ArticleDelete': Before an article is deleted.
$wikiPage: the WikiPage (object) being deleted
$user: the user (object) deleting the article
$reason: the reason (string) the article is being deleted
$error: if the deletion was prohibited, the (raw HTML) error message to display
  (added in 1.13)
$status: Status object, modify this to throw an error. Overridden by $error
  (added in 1.20)

'ArticleDeleteAfterSuccess': Output after an article has been deleted.
$title: Title of the article that has been deleted.
$outputPage: OutputPage that can be used to append the output.

'ArticleDeleteComplete': After an article is deleted.
$wikiPage: the WikiPage that was deleted
$user: the user that deleted the article
$reason: the reason the article was deleted
$id: id of the article that was deleted
$content: the Content of the deleted page
$logEntry: the ManualLogEntry used to record the deletion

'ArticleEditUpdateNewTalk': Before updating user_newtalk when a user talk page
was changed.
&$wikiPage: WikiPage (object) of the user talk page
$recipient: User (object) who's talk page was edited

'ArticleEditUpdates': When edit updates (mainly link tracking) are made when an
article has been changed.
$wikiPage: the WikiPage (object)
$editInfo: data holder that includes the parser output ($editInfo->output) for
  that page after the change
$changed: bool for if the page was changed

'ArticleEditUpdatesDeleteFromRecentchanges': Before deleting old entries from
recentchanges table, return false to not delete old entries.
$wikiPage: WikiPage (object) being modified

'ArticleFromTitle': when creating an article object from a title object using
Wiki::articleFromTitle().
$title: Title (object) used to create the article object
$article: Article (object) that will be returned
$context: IContextSource (object)

'ArticleInsertComplete': DEPRECATED! Use PageContentInsertComplete.
After a new article is created.
$wikiPage: WikiPage created
$user: User creating the article
$text: New content
$summary: Edit summary/comment
$isMinor: Whether or not the edit was marked as minor
$isWatch: (No longer used)
$section: (No longer used)
$flags: Flags passed to WikiPage::doEditContent()
$revision: New Revision of the article

'ArticleMergeComplete': After merging to article using Special:Mergehistory.
$targetTitle: target title (object)
$destTitle: destination title (object)

'ArticlePageDataAfter': After loading data of an article from the database.
$wikiPage: WikiPage (object) whose data were loaded
$row: row (object) returned from the database server

'ArticlePageDataBefore': Before loading data of an article from the database.
$wikiPage: WikiPage (object) that data will be loaded
$fields: fields (array) to load from the database

'ArticlePrepareTextForEdit': Called when preparing text to be saved.
$wikiPage: the WikiPage being saved
$popts: parser options to be used for pre-save transformation

'ArticleProtect': Before an article is protected.
$wikiPage: the WikiPage being protected
$user: the user doing the protection
$protect: boolean whether this is a protect or an unprotect
$reason: Reason for protect
$moveonly: boolean whether this is for move only or not

'ArticleProtectComplete': After an article is protected.
$wikiPage: the WikiPage that was protected
$user: the user who did the protection
$protect: boolean whether it was a protect or an unprotect
$reason: Reason for protect
$moveonly: boolean whether it was for move only or not

'ArticlePurge': Before executing "&action=purge".
$wikiPage: WikiPage (object) to purge

'ArticleRevisionUndeleted': After an article revision is restored.
$title: the article title
$revision: the revision
$oldPageID: the page ID of the revision when archived (may be null)

'ArticleRevisionVisibilitySet': Called when changing visibility of one or more
revisions of an article.
$title: Title object of the article
$ids: Ids to set the visibility for

'ArticleRollbackComplete': After an article rollback is completed.
$wikiPage: the WikiPage that was edited
$user: the user who did the rollback
$revision: the revision the page was reverted back to
$current: the reverted revision

'ArticleSave': DEPRECATED! Use PageContentSave instead.
Before an article is saved.
$wikiPage: the WikiPage (object) being saved
$user: the user (object) saving the article
$text: the new article text
$summary: the article summary (comment)
$isminor: minor flag
$iswatch: watch flag
$section: section #

'ArticleSaveComplete': DEPRECATED! Use PageContentSaveComplete instead.
After an article has been updated.
$wikiPage: WikiPage modified
$user: User performing the modification
$text: New content
$summary: Edit summary/comment
$isMinor: Whether or not the edit was marked as minor
$isWatch: (No longer used)
$section: (No longer used)
$flags: Flags passed to WikiPage::doEditContent()
$revision: New Revision of the article
$status: Status object about to be returned by doEditContent()
$baseRevId: the rev ID (or false) this edit was based on

'ArticleUndelete': When one or more revisions of an article are restored.
$title: Title corresponding to the article restored
$create: Whether or not the restoration caused the page to be created (i.e. it
  didn't exist before).
$comment: The comment associated with the undeletion.
$oldPageId: ID of page previously deleted (from archive table)

'ArticleUndeleteLogEntry': When a log entry is generated but not yet saved.
$pageArchive: the PageArchive object
&$logEntry: ManualLogEntry object
$user: User who is performing the log action

'ArticleUpdateBeforeRedirect': After a page is updated (usually on save), before
the user is redirected back to the page.
&$article: the article
&$sectionanchor: The section anchor link (e.g. "#overview" )
&$extraq: Extra query parameters which can be added via hooked functions

'ArticleViewCustom': DEPRECATED! Use ArticleContentViewCustom instead.
Allows to output the text of the article in a different format than wikitext.
Note that it is preferable to implement proper handing for a custom data type
using the ContentHandler facility.
$text: text of the page
$title: title of the page
$output: reference to $wgOut

'ArticleViewFooter': After showing the footer section of an ordinary page view
$article: Article object
$patrolFooterShown: boolean whether patrol footer is shown

'ArticleViewHeader': Before the parser cache is about to be tried for article
viewing.
&$article: the article
&$pcache: whether to try the parser cache or not
&$outputDone: whether the output for this page finished or not. Set to
  a ParserOutput object to both indicate that the output is done and what
  parser output was used.

'ArticleViewRedirect': Before setting "Redirected from ..." subtitle when a
redirect was followed.
$article: target article (object)

'AuthPluginAutoCreate': Called when creating a local account for an user logged
in from an external authentication method.
$user: User object created locally

'AuthPluginSetup': Update or replace authentication plugin object ($wgAuth).
Gives a chance for an extension to set it programmatically to a variable class.
&$auth: the $wgAuth object, probably a stub

'AutopromoteCondition': Check autopromote condition for user.
$type: condition type
$args: arguments
$user: user
$result: result of checking autopromote condition

'BacklinkCacheGetConditions': Allows to set conditions for query when links to
certain title are fetched.
$table: table name
$title: title of the page to which backlinks are sought
&$conds: query conditions

'BacklinkCacheGetPrefix': Allows to set prefix for a specific link table.
$table: table name
&$prefix: prefix

'BadImage': When checking against the bad image list. Change $bad and return
false to override. If an image is "bad", it is not rendered inline in wiki
pages or galleries in category pages.
$name: Image name being checked
&$bad: Whether or not the image is "bad"

'BaseTemplateAfterPortlet': After output of portlets, allow injecting
custom HTML after the section. Any uses of the hook need to handle escaping.
$template BaseTemplate
$portlet: string portlet name
&$html: string

'BaseTemplateToolbox': Called by BaseTemplate when building the $toolbox array
and returning it for the skin to output. You can add items to the toolbox while
still letting the skin make final decisions on skin-specific markup conventions
using this hook.
&$sk: The BaseTemplate base skin template
&$toolbox: An array of toolbox items, see BaseTemplate::getToolbox and
  BaseTemplate::makeListItem for details on the format of individual items
  inside of this array.

'BeforeDisplayNoArticleText': Before displaying message key "noarticletext" or
"noarticletext-nopermission" at Article::showMissingArticle().
$article: article object

'BeforeHttpsRedirect': Prior to forcing HTTP->HTTPS redirect. Gives a chance to
override how the redirect is output by modifying, or by returning false, and
letting standard HTTP rendering take place.
ATTENTION: This hook is likely to be removed soon due to overall design of the
system.
$context: IContextSource object
&$redirect: string URL, modifiable

'BeforeInitialize': Before anything is initialized in
MediaWiki::performRequest().
&$title: Title being used for request
$unused: null
&$output: OutputPage object
&$user: User
$request: WebRequest object
$mediaWiki: Mediawiki object

'BeforePageDisplay': Prior to outputting a page.
&$out: OutputPage object
&$skin: Skin object

'BeforePageRedirect': Prior to sending an HTTP redirect. Gives a chance to
override how the redirect is output by modifying, or by returning false and
taking over the output.
$out: OutputPage object
&$redirect: URL, modifiable
&$code: HTTP code (eg '301' or '302'), modifiable

'BeforeParserFetchFileAndTitle': Before an image is rendered by Parser.
$parser: Parser object
$nt: the image title
&$options: array of options to RepoGroup::findFile. If it contains 'broken'
  as a key then the file will appear as a broken thumbnail.
&$descQuery: query string to add to thumbnail URL

'BeforeParserFetchTemplateAndtitle': Before a template is fetched by Parser.
$parser: Parser object
$title: title of the template
&$skip: skip this template and link it?
&$id: the id of the revision being parsed

'BeforeParserrenderImageGallery': Before an image gallery is rendered by Parser.
&$parser: Parser object
&$ig: ImageGallery object

'BeforeWelcomeCreation': Before the welcomecreation message is displayed to a
newly created user.
&$welcome_creation_msg: MediaWiki message name to display on the welcome screen
  to a newly created user account.
&$injected_html: Any HTML to inject after the "logged in" message of a newly
  created user account

'BitmapHandlerCheckImageArea': By BitmapHandler::normaliseParams, after all
normalizations have been performed, except for the $wgMaxImageArea check.
$image: File
&$params: Array of parameters
&$checkImageAreaHookResult: null, set to true or false to override the
  $wgMaxImageArea check result.

'BitmapHandlerTransform': before a file is transformed, gives extension the
possibility to transform it themselves
$handler: BitmapHandler
$image: File
&$scalerParams: Array with scaler parameters
&$mto: null, set to a MediaTransformOutput

'BlockIp': Before an IP address or user is blocked.
$block: the Block object about to be saved
$user: the user _doing_ the block (not the one being blocked)
&$reason: if the hook is aborted, the error message to be returned in an array

'BlockIpComplete': After an IP address or user is blocked.
$block: the Block object that was saved
$user: the user who did the block (not the one being blocked)

'BookInformation': Before information output on Special:Booksources.
$isbn: ISBN to show information for
$output: OutputPage object in use

'CanIPUseHTTPS': Determine whether the client at a given source IP is likely
to be able to access the wiki via HTTPS.
$ip: The IP address in human-readable form
&$canDo: This reference should be set to false if the client may not be able
  to use HTTPS

'CanonicalNamespaces': For extensions adding their own namespaces or altering
the defaults.
Note that if you need to specify namespace protection or content model for
a namespace that is added in a CanonicalNamespaces hook handler, you
should do so by altering $wgNamespaceProtection and
$wgNamespaceContentModels outside the handler, in top-level scope. The
point at which the CanonicalNamespaces hook fires is too late for altering
these variables. This applies even if the namespace addition is
conditional; it is permissible to declare a content model and protection
for a namespace and then decline to actually register it.
&$namespaces: Array of namespace numbers with corresponding canonical names

'CategoryAfterPageAdded': After a page is added to a category.
$category: Category that page was added to
$wikiPage: WikiPage that was added

'CategoryAfterPageRemoved': After a page is removed from a category.
$category: Category that page was removed from
$wikiPage: WikiPage that was removed

'CategoryPageView': Before viewing a categorypage in CategoryPage::view.
$catpage: CategoryPage instance

'CategoryViewer::doCategoryQuery': After querying for pages to be displayed
in a Category page. Gives extensions the opportunity to batch load any
related data about the pages.
$type: The category type. Either 'page', 'file' or 'subcat'
$res: Query result from DatabaseBase::select()

'CategoryViewer::generateLink': Before generating an output link allow
extensions opportunity to generate a more specific or relevant link.
$type: The category type. Either 'page', 'img' or 'subcat'
$title: Title object for the categorized page
$html: Requested html content of anchor
&$link: Returned value. When set to a non-null value by a hook subscriber
  this value will be used as the anchor instead of Linker::link

'ChangePasswordForm': For extensions that need to add a field to the
ChangePassword form via the Preferences form.
&$extraFields: An array of arrays that hold fields like would be passed to the
  pretty function.

'ChangesListInitRows': Batch process change list rows prior to rendering.
$changesList: ChangesList instance
$rows: The data that will be rendered. May be a ResultWrapper instance or
  an array.

'ChangesListInsertArticleLink': Override or augment link to article in RC list.
&$changesList: ChangesList instance.
&$articlelink: HTML of link to article (already filled-in).
&$s: HTML of row that is being constructed.
&$rc: RecentChange instance.
$unpatrolled: Whether or not we are showing unpatrolled changes.
$watched: Whether or not the change is watched by the user.

'ChangesListSpecialPageFilters': Called after building form options on pages
inheriting from ChangesListSpecialPage (in core: RecentChanges,
RecentChangesLinked and Watchlist).
$special: ChangesListSpecialPage instance
&$filters: associative array of filter definitions. The keys are the HTML
  name/URL parameters. Each key maps to an associative array with a 'msg'
  (message key) and a 'default' value.

'ChangesListSpecialPageQuery': Called when building SQL query on pages
inheriting from ChangesListSpecialPage (in core: RecentChanges,
RecentChangesLinked and Watchlist).
$name: name of the special page, e.g. 'Watchlist'
&$tables: array of tables to be queried
&$fields: array of columns to select
&$conds: array of WHERE conditionals for query
&$query_options: array of options for the database request
&$join_conds: join conditions for the tables
$opts: FormOptions for this request

'ChangeTagAfterDelete': Called after a change tag has been deleted (that is,
removed from all revisions and log entries to which it was applied). This gives
extensions a chance to take it off their books.
$tag: name of the tag
&$status: Status object. Add warnings to this as required. There is no point
  setting errors, as the deletion has already been partly carried out by this
  point.

'ChangeTagCanCreate': Tell whether a change tag should be able to be created
from the UI (Special:Tags) or via the API. You could use this hook if you want
to reserve a specific "namespace" of tags, or something similar.
$tag: name of the tag
$user: user initiating the action
&$status: Status object. Add your errors using `$status->fatal()` or warnings
  using `$status->warning()`. Errors and warnings will be relayed to the user.
  If you set an error, the user will be unable to create the tag.

'ChangeTagCanDelete': Tell whether a change tag should be able to be
deleted from the UI (Special:Tags) or via the API. The default is that tags
defined using the ListDefinedTags hook are not allowed to be deleted unless
specifically allowed. If you wish to allow deletion of the tag, set
`$status = Status::newGood()` to allow deletion, and then `return false` from
the hook function. Ensure you consume the 'ChangeTagAfterDelete' hook to carry
out custom deletion actions.
$tag: name of the tag
$user: user initiating the action
&$status: Status object. See above.

'ChangeTagsListActive': Allows you to nominate which of the tags your extension
uses are in active use.
&$tags: list of all active tags. Append to this array.

'Collation::factory': Called if $wgCategoryCollation is an unknown collation.
$collationName: Name of the collation in question
&$collationObject: Null. Replace with a subclass of the Collation class that
  implements the collation given in $collationName.

'ConfirmEmailComplete': Called after a user's email has been confirmed
successfully.
$user: user (object) whose email is being confirmed

'ContentAlterParserOutput': Modify parser output for a given content object.
Called by Content::getParserOutput after parsing has finished. Can be used
for changes that depend on the result of the parsing but have to be done
before LinksUpdate is called (such as adding tracking categories based on
the rendered HTML).
$content: The Content to render
$title: Title of the page, as context
$parserOutput: ParserOutput to manipulate

'ContentGetParserOutput': Customize parser output for a given content object,
called by AbstractContent::getParserOutput. May be used to override the normal
model-specific rendering of page content.
$content: The Content to render
$title: Title of the page, as context
$revId: The revision ID, as context
$options: ParserOptions for rendering. To avoid confusing the parser cache,
  the output can only depend on parameters provided to this hook function, not
  on global state.
$generateHtml: boolean, indicating whether full HTML should be generated. If
  false, generation of HTML may be skipped, but other information should still
  be present in the ParserOutput object.
&$output: ParserOutput, to manipulate or replace

'ContentHandlerDefaultModelFor': Called when the default content model is
determined for a given title. May be used to assign a different model for that
title.
$title: the Title in question
&$model: the model name. Use with CONTENT_MODEL_XXX constants.

'ContentHandlerForModelID': Called when a ContentHandler is requested for
a given content model name, but no entry for that model exists in
$wgContentHandlers.
$modeName: the requested content model name
&$handler: set this to a ContentHandler object, if desired.

'ContentModelCanBeUsedOn': Called to determine whether that content model can
be used on a given page. This is especially useful to prevent some content
models to be used in some special location.
$contentModel: ID of the content model in question
$title: the Title in question.
&$ok: Output parameter, whether it is OK to use $contentModel on $title.
  Handler functions that modify $ok should generally return false to prevent
  further hooks from further modifying $ok.

'ContribsPager::getQueryInfo': Before the contributions query is about to run
&$pager: Pager object for contributions
&$queryInfo: The query for the contribs Pager

'ContribsPager::reallyDoQuery': Called before really executing the query for My
Contributions
&$data: an array of results of all contribs queries
$pager: The ContribsPager object hooked into
$offset: Index offset, inclusive
$limit: Exact query limit
$descending: Query direction, false for ascending, true for descending

'ContributionsLineEnding': Called before a contributions HTML line is finished
$page: SpecialPage object for contributions
&$ret: the HTML line
$row: the DB row for this line
&$classes: the classes to add to the surrounding <li>

'ContributionsToolLinks': Change tool links above Special:Contributions
$id: User identifier
$title: User page title
&$tools: Array of tool links

'ConvertContent': Called by AbstractContent::convert when a conversion to
another content model is requested.
Handler functions that modify $result should generally return false to disable
further attempts at conversion.
$content: The Content object to be converted.
$toModel: The ID of the content model to convert to.
$lossy:   boolean indicating whether lossy conversion is allowed.
&$result: Output parameter, in case the handler function wants to provide a
  converted Content object. Note that $result->getContentModel() must return
  $toModel.

'CustomEditor': When invoking the page editor
Return true to allow the normal editor to be used, or false if implementing
a custom editor, e.g. for a special namespace, etc.
$article: Article being edited
$user: User performing the edit

'DatabaseOraclePostInit': Called after initialising an Oracle database
&$db: the DatabaseOracle object

'DeletedContribsPager::reallyDoQuery': Called before really executing the query
for Special:DeletedContributions
Similar to ContribsPager::reallyDoQuery
&$data: an array of results of all contribs queries
$pager: The DeletedContribsPager object hooked into
$offset: Index offset, inclusive
$limit: Exact query limit
$descending: Query direction, false for ascending, true for descending

'DeletedContributionsLineEnding': Called before a DeletedContributions HTML line
is finished.
Similar to ContributionsLineEnding
$page: SpecialPage object for DeletedContributions
&$ret: the HTML line
$row: the DB row for this line
&$classes: the classes to add to the surrounding <li>

'DiffRevisionTools': Override or extend the revision tools available from the
diff view, i.e. undo, etc.
$newRev: Revision object of the "new" revision
&$links: Array of HTML links
$oldRev: Revision object of the "old" revision (may be null)

'DiffViewHeader': Called before diff display
$diff: DifferenceEngine object that's calling
$oldRev: Revision object of the "old" revision (may be null/invalid)
$newRev: Revision object of the "new" revision

'DisplayOldSubtitle': before creating subtitle when browsing old versions of
an article
$article: article (object) being viewed
$oldid: oldid (int) being viewed

'DoEditSectionLink': DEPRECATED! Use SkinEditSectionLinks instead.
Override the HTML generated for section edit links
$skin: Skin object rendering the UI
$title: Title object for the title being linked to (may not be the same as
  the page title, if the section is included from a template)
$section: The designation of the section being pointed to, to be included in
  the link, like "&section=$section"
$tooltip: The default tooltip.  Escape before using.
  By default, this is wrapped in the 'editsectionhint' message.
&$result: The HTML to return, prefilled with the default plus whatever other
  changes earlier hooks have made
$lang: The language code to use for the link in the wfMessage function

'EditFilter': Perform checks on an edit
$editor: EditPage instance (object). The edit form (see includes/EditPage.php)
$text: Contents of the edit box
$section: Section being edited
&$error: Error message to return
$summary: Edit summary for page

'EditFilterMerged': DEPRECATED! Use EditFilterMergedContent instead.
Post-section-merge edit filter.
$editor: EditPage instance (object)
$text: content of the edit box
&$error: error message to return
$summary: Edit summary for page

'EditFilterMergedContent': Post-section-merge edit filter.
This may be triggered by the EditPage or any other facility that modifies page
content. Use the $status object to indicate whether the edit should be allowed,
and to provide a reason for disallowing it. Return false to abort the edit, and
true to continue. Returning true if $status->isOK() returns false means "don't
save but continue user interaction", e.g. show the edit form.
$status->apiHookResult can be set to an array to be returned by api.php
action=edit. This is used to deliver captchas.
$context: object implementing the IContextSource interface.
$content: content of the edit box, as a Content object.
$status: Status object to represent errors, etc.
$summary: Edit summary for page
$user: the User object representing the user whois performing the edit.
$minoredit: whether the edit was marked as minor by the user.

'EditFormInitialText': Allows modifying the edit form when editing existing
pages
$editPage: EditPage object

'EditFormPreloadText': Allows population of the edit form when creating
new pages
&$text: Text to preload with
&$title: Title object representing the page being created

'EditPage::attemptSave': Called before an article is
saved, that is before WikiPage::doEditContent() is called
$editpage_Obj: the current EditPage object

'EditPage::attemptSave:after': Called after an article save attempt
$editpage_Obj: the current EditPage object
$status: the resulting Status object
$resultDetails: Result details array

'EditPage::importFormData': allow extensions to read additional data
posted in the form
$editpage: EditPage instance
$request: Webrequest
return value is ignored (should always return true)

'EditPage::showEditForm:fields': allows injection of form field into edit form
Return value is ignored (should always return true)
$editor: the EditPage instance for reference
$out: an OutputPage instance to write to

'EditPage::showEditForm:initial': before showing the edit form
Return false to halt editing; you'll need to handle error messages, etc.
yourself. Alternatively, modifying $error and returning true will cause the
contents of $error to be echoed at the top of the edit form as wikitext.
Return true without altering $error to allow the edit to proceed.
$editor: EditPage instance (object)
$out: an OutputPage instance to write to

'EditPage::showReadOnlyForm:initial': similar to EditPage::showEditForm:initial
but for the read-only 'view source' variant of the edit form.
Return value is ignored (should always return true)
$editor: EditPage instance (object)
&$out: an OutputPage instance to write to

'EditPage::showStandardInputs:options': allows injection of form fields into
the editOptions area
Return value is ignored (should always be true)
$editor: EditPage instance (object)
$out: an OutputPage instance to write to
&$tabindex: HTML tabindex of the last edit check/button

'EditPageBeforeConflictDiff': allows modifying the EditPage object and output
when there's an edit conflict.  Return false to halt normal diff output; in
this case you're responsible for computing and outputting the entire "conflict"
part, i.e., the "difference between revisions" and "your text" headers and
sections.
&$editor: EditPage instance
&$out: OutputPage instance

'EditPageBeforeEditButtons': Allows modifying the edit buttons below the
textarea in the edit form.
&$editpage: The current EditPage object
&$buttons: Array of edit buttons "Save", "Preview", "Live", and "Diff"
&$tabindex: HTML tabindex of the last edit check/button

'EditPageBeforeEditChecks': Allows modifying the edit checks below the textarea
in the edit form.
&$editpage: The current EditPage object
&$checks: Array of edit checks like "watch this page"/"minor edit"
&$tabindex: HTML tabindex of the last edit check/button

'EditPageBeforeEditToolbar': Allows modifying the edit toolbar above the
textarea in the edit form.
&$toolbar: The toolbar HTMl

'EditPageCopyrightWarning': Allow for site and per-namespace customization of
contribution/copyright notice.
$title: title of page being edited
&$msg: localization message name, overridable. Default is either
  'copyrightwarning' or 'copyrightwarning2'.

'EditPageGetDiffContent': Allow modifying the wikitext that will be used in
"Show changes". Note that it is preferable to implement diff handling for
different data types using the ContentHandler facility.
$editPage: EditPage object
&$newtext: wikitext that will be used as "your version"

'EditPageGetDiffText': DEPRECATED! Use EditPageGetDiffContent instead.
Allow modifying the wikitext that will be used in "Show changes". Note that it
is preferable to implement diff handling for different data types using the
ContentHandler facility.
$editPage: EditPage object
&$newtext: wikitext that will be used as "your version"

'EditPageGetPreviewContent': Allow modifying the wikitext that will be
previewed. Note that it is preferable to implement previews for different data
types using the ContentHandler facility.
$editPage: EditPage object
&$content: Content object to be previewed (may be replaced by hook function)

'EditPageGetPreviewText': DEPRECATED! Use EditPageGetPreviewContent instead.
Allow modifying the wikitext that will be previewed. Note that it is preferable
to implement previews for different data types using the ContentHandler
facility.
$editPage: EditPage object
&$toparse: wikitext that will be parsed

'EditPageNoSuchSection': When a section edit request is given for an
non-existent section
&$editpage: The current EditPage object
&$res: the HTML of the error text

'EditPageTosSummary': Give a chance for site and per-namespace customizations
of terms of service summary link that might exist separately from the copyright
notice.
$title: title of page being edited
&$msg: localization message name, overridable. Default is 'editpage-tos-summary'

'EmailConfirmed': When checking that the user's email address is "confirmed".
This runs before the other checks, such as anonymity and the real check; return
true to allow those checks to occur, and false if checking is done.
$user: User being checked
$confirmed: Whether or not the email address is confirmed

'EmailUser': Before sending email from one user to another.
$to: MailAddress object of receiving user
$from: MailAddress object of sending user
$subject: subject of the mail
$text: text of the mail
&$error: Out-param for an error

'EmailUserCC': Before sending the copy of the email to the author.
$to: MailAddress object of receiving user
$from: MailAddress object of sending user
$subject: subject of the mail
$text: text of the mail

'EmailUserComplete': After sending email from one user to another.
$to: MailAddress object of receiving user
$from: MailAddress object of sending user
$subject: subject of the mail
$text: text of the mail

'EmailUserForm': After building the email user form object.
$form: HTMLForm object

'EmailUserPermissionsErrors': to retrieve permissions errors for emailing a
user.
$user: The user who is trying to email another user.
$editToken: The user's edit token.
&$hookErr: Out-param for the error. Passed as the parameters to
  OutputPage::showErrorPage.

'EnhancedChangesList::getLogText': to alter, remove or add to the links of a
group of changes in EnhancedChangesList.
Hook subscribers can return false to omit this line from recentchanges.
$changesList: EnhancedChangesList object
&$links: The links that were generated by EnhancedChangesList
$block: The RecentChanges objects in that block

'EnhancedChangesListModifyLineData': to alter data used to build
a grouped recent change inner line in EnhancedChangesList.
Hook subscribers can return false to omit this line from recentchanges.
$changesList: EnhancedChangesList object
&$data: An array with all the components that will be joined in order to create the line
$block: An array of RecentChange objects in that block
$rc: The RecentChange object for this line

'EnhancedChangesListModifyBlockLineData': to alter data used to build
a non-grouped recent change line in EnhancedChangesList.
$changesList: EnhancedChangesList object
&$data: An array with all the components that will be joined in order to create the line
$rc: The RecentChange object for this line

'ExemptFromAccountCreationThrottle': Exemption from the account creation
throttle.
$ip: The ip address of the user

'ExtensionTypes': Called when generating the extensions credits, use this to
change the tables headers.
&$extTypes: associative array of extensions types

'ExtractThumbParameters': DEPRECATED! Media handler should override
MediaHandler::parseParamString instead.
Called when extracting thumbnail parameters from a thumbnail file name.
$thumbname: the base name of the thumbnail file
&$params: the currently extracted params (has source name, temp or archived
zone)

'FetchChangesList': When fetching the ChangesList derivative for a particular
user.
$user: User the list is being fetched for
&$skin: Skin object to be used with the list
&$list: List object (defaults to NULL, change it to an object instance and
  return false override the list derivative used)

'FileDeleteComplete': When a file is deleted.
$file: reference to the deleted file
$oldimage: in case of the deletion of an old image, the name of the old file
$article: in case all revisions of the file are deleted a reference to the
  WikiFilePage associated with the file.
$user: user who performed the deletion
$reason: reason

'FileTransformed': When a file is transformed and moved into storage.
$file: reference to the File object
$thumb: the MediaTransformOutput object
$tmpThumbPath: The temporary file system path of the transformed file
$thumbPath: The permanent storage path of the transformed file

'FileUndeleteComplete': When a file is undeleted
$title: title object to the file
$fileVersions: array of undeleted versions. Empty if all versions were restored
$user: user who performed the undeletion
$reason: reason

'FileUpload': When a file upload occurs.
$file : Image object representing the file that was uploaded
$reupload : Boolean indicating if there was a previously another image there or
  not (since 1.17)
$hasDescription : Boolean indicating that there was already a description page
  and a new one from the comment wasn't created (since 1.17)

'FormatAutocomments': When an autocomment is formatted by the Linker.
&$comment: Reference to the accumulated comment. Initially null, when set the
  default code will be skipped.
$pre: Boolean, true if there is text before this autocomment
$auto: The extracted part of the parsed comment before the call to the hook.
$post: Boolean, true if there is text after this autocomment
$title: An optional title object used to links to sections. Can be null.
$local: Boolean indicating whether section links should refer to local page.
$wikiId: String containing the ID (as used by WikiMap) of the wiki from which the
  autocomment originated; null for the local wiki. Added in 1.26, should default
  to null in handler functions, for backwards compatibility.

'GalleryGetModes': Get list of classes that can render different modes of a
gallery.
&$modeArray: An associative array mapping mode names to classes that implement
  that mode. It is expected all registered classes are a subclass of
  ImageGalleryBase.

'GetAutoPromoteGroups': When determining which autopromote groups a user is
entitled to be in.
&$user: user to promote.
&$promote: groups that will be added.

'GetBlockedStatus': after loading blocking status of an user from the database
$user: user (object) being checked

'GetCacheVaryCookies': Get cookies that should vary cache options.
$out: OutputPage object
&$cookies: array of cookies name, add a value to it if you want to add a cookie
  that have to vary cache options

'GetCanonicalURL': Modify fully-qualified URLs used for IRC and e-mail
notifications.
$title: Title object of page
$url: string value as output (out parameter, can modify)
$query: query options passed to Title::getCanonicalURL()

'GetDefaultSortkey': Override the default sortkey for a page.
$title: Title object that we need to get a sortkey for
&$sortkey: Sortkey to use.

'GetDifferenceEngine': Called when getting a new difference engine interface
object Return false for valid object in $differenceEngine or true for the
default difference engine.
$context: IContextSource context to be used for diff
$old: Revision ID to show and diff with
$new: Either a revision ID or one of the strings 'cur', 'prev' or 'next'
$refreshCache: If set, refreshes the diff cache
$unhide: If set, allow viewing deleted revs
&$differenceEngine: output parameter, difference engine object to be used for
  diff

'GetDoubleUnderscoreIDs': Modify the list of behavior switch (double
underscore) magic words. Called by MagicWord.
&$doubleUnderscoreIDs: array of strings

'GetExtendedMetadata': Get extended file metadata for the API
&$combinedMeta: Array of the form:
	'MetadataPropName' => array(
		value' => prop value,
		'source' => 'name of hook'
	).
$file: File object of file in question
$context: RequestContext (including language to use)
$single: Only extract the current language; if false, the prop value should
  be in the metadata multi-language array format:
  mediawiki.org/wiki/Manual:File_metadata_handling#Multi-language_array_format
&$maxCacheTime: how long the results can be cached

'GetFullURL': Modify fully-qualified URLs used in redirects/export/offsite data.
$title: Title object of page
$url: string value as output (out parameter, can modify)
$query: query options passed to Title::getFullURL()

'GetHumanTimestamp': Pre-emptively override the human-readable timestamp
generated by MWTimestamp::getHumanTimestamp(). Return false in this hook to use
the custom output.
&$output: string for the output timestamp
$timestamp: MWTimestamp object of the current (user-adjusted) timestamp
$relativeTo: MWTimestamp object of the relative (user-adjusted) timestamp
$user: User whose preferences are being used to make timestamp
$lang: Language that will be used to render the timestamp

'GetInternalURL': Modify fully-qualified URLs used for squid cache purging.
$title: Title object of page
$url: string value as output (out parameter, can modify)
$query: query options passed to Title::getInternalURL()

'GetIP': modify the ip of the current user (called only once).
&$ip: string holding the ip as determined so far

'GetLinkColours': modify the CSS class of an array of page links.
$linkcolour_ids: array of prefixed DB keys of the pages linked to,
  indexed by page_id.
&$colours: (output) array of CSS classes, indexed by prefixed DB keys

'GetLocalURL': Modify local URLs as output into page links. Note that if you are
working with internal urls (non-interwiki) then it may be preferable to work
with the GetLocalURL::Internal or GetLocalURL::Article hooks as GetLocalURL can
be buggy for internal urls on render if you do not re-implement the horrible
hack that Title::getLocalURL uses in your own extension.
$title: Title object of page
&$url: string value as output (out parameter, can modify)
$query: query options passed to Title::getLocalURL()

'GetLocalURL::Article': Modify local URLs specifically pointing to article paths
without any fancy queries or variants.
$title: Title object of page
&$url: string value as output (out parameter, can modify)

'GetLocalURL::Internal': Modify local URLs to internal pages.
$title: Title object of page
&$url: string value as output (out parameter, can modify)
$query: query options passed to Title::getLocalURL()

'GetLogTypesOnUser': Add log types where the target is a userpage
&$types: Array of log types

'GetMetadataVersion': Modify the image metadata version currently in use. This
is used when requesting image metadata from a ForeignApiRepo. Media handlers
that need to have versioned metadata should add an element to the end of the
version array of the form 'handler_name=version'. Most media handlers won't need
to do this unless they broke backwards compatibility with a previous version of
the media handler metadata output.
&$version: Array of version strings

'GetNewMessagesAlert': Disable or modify the new messages alert
&$newMessagesAlert: An empty string by default. If the user has new talk page
  messages, this should be populated with an alert message to that effect
$newtalks: An empty array if the user has no new messages or an array
  containing links and revisions if there are new messages (See
  User::getNewMessageLinks)
$user: The user object of the user who is loading the page
$out: OutputPage object (to check what type of page the user is on)

'GetPreferences': Modify user preferences.
$user: User whose preferences are being modified.
&$preferences: Preferences description array, to be fed to an HTMLForm object

'GetRelativeTimestamp': Pre-emptively override the relative timestamp generated
by MWTimestamp::getRelativeTimestamp(). Return false in this hook to use the
custom output.
&$output: string for the output timestamp
&$diff: DateInterval representing the difference between the timestamps
$timestamp: MWTimestamp object of the current (user-adjusted) timestamp
$relativeTo: MWTimestamp object of the relative (user-adjusted) timestamp
$user: User whose preferences are being used to make timestamp
$lang: Language that will be used to render the timestamp

'getUserPermissionsErrors': Add a permissions error when permissions errors are
checked for. Use instead of userCan for most cases. Return false if the user
can't do it, and populate $result with the reason in the form of
array( messagename, param1, param2, ... ). For consistency, error messages
should be plain text with no special coloring, bolding, etc. to show that
they're errors; presenting them properly to the user as errors is done by the
caller.
$title: Title object being checked against
$user: Current user object
$action: Action being checked
$result: User permissions error to add. If none, return true.

'getUserPermissionsErrorsExpensive': Equal to getUserPermissionsErrors, but is
called only if expensive checks are enabled. Add a permissions error when
permissions errors are checked for. Return false if the user can't do it, and
populate $result with the reason in the form of array( messagename, param1,
param2, ... ). For consistency, error messages should be plain text with no
special coloring, bolding, etc. to show that they're errors; presenting them
properly to the user as errors is done by the caller.
$title: Title object being checked against
$user: Current user object
$action: Action being checked
$result: User permissions error to add. If none, return true.

'GitViewers': Called when generating the list of git viewers for
Special:Version, use this to change the list.
&$extTypes: associative array of repo URLS to viewer URLs.

'HistoryRevisionTools': Override or extend the revision tools available from the
page history view, i.e. undo, rollback, etc.
$rev: Revision object
&$links: Array of HTML links

'HTMLFileCache::useFileCache': Override whether a page should be cached in file
cache.
$context: An IContextSource object with information about the request being
  served.

'ImageBeforeProduceHTML': Called before producing the HTML created by a wiki
image insertion. You can skip the default logic entirely by returning false, or
just modify a few things using call-by-reference.
&$skin: Skin object
&$title: Title object of the image
&$file: File object, or false if it doesn't exist
&$frameParams: Various parameters with special meanings; see documentation in
  includes/Linker.php for Linker::makeImageLink
&$handlerParams: Various parameters with special meanings; see documentation in
  includes/Linker.php for Linker::makeImageLink
&$time: Timestamp of file in 'YYYYMMDDHHIISS' string form, or false for current
&$res: Final HTML output, used if you return false

'ImageOpenShowImageInlineBefore': Call potential extension just before showing
the image on an image page.
$imagePage: ImagePage object ($this)
$output: $wgOut

'ImagePageAfterImageLinks': Called after the image links section on an image
page is built.
$imagePage: ImagePage object ($this)
&$html: HTML for the hook to add

'ImagePageFileHistoryLine': Called when a file history line is constructed.
$file: the file
$line: the HTML of the history line
$css: the line CSS class

'ImagePageFindFile': Called when fetching the file associated with an image
page.
$page: ImagePage object
&$file: File object
&$displayFile: displayed File object

'ImagePageShowTOC': Called when the file toc on an image page is generated.
$page: ImagePage object
&$toc: Array of <li> strings

'ImgAuthBeforeStream': executed before file is streamed to user, but only when
using img_auth.php.
&$title: the Title object of the file as it would appear for the upload page
&$path: the original file and path name when img_auth was invoked by the web
  server
&$name: the name only component of the file
&$result: The location to pass back results of the hook routine (only used if
  failed)
  $result[0]=The index of the header message
  $result[1]=The index of the body text message
  $result[2 through n]=Parameters passed to body text message. Please note the
  header message cannot receive/use parameters.

'ImportHandleLogItemXMLTag': When parsing a XML tag in a log item.
Return false to stop further processing of the tag
$reader: XMLReader object
$logInfo: Array of information

'ImportHandlePageXMLTag': When parsing a XML tag in a page.
Return false to stop further processing of the tag
$reader: XMLReader object
$pageInfo: Array of information

'ImportHandleRevisionXMLTag': When parsing a XML tag in a page revision.
Return false to stop further processing of the tag
$reader: XMLReader object
$pageInfo: Array of page information
$revisionInfo: Array of revision information

'ImportHandleToplevelXMLTag': When parsing a top level XML tag.
Return false to stop further processing of the tag
$reader: XMLReader object

'ImportHandleUploadXMLTag': When parsing a XML tag in a file upload.
Return false to stop further processing of the tag
$reader: XMLReader object
$revisionInfo: Array of information

'InfoAction': When building information to display on the action=info page.
$context: IContextSource object
&$pageInfo: Array of information

'InitializeArticleMaybeRedirect': MediaWiki check to see if title is a redirect.
$title: Title object for the current page
$request: WebRequest
$ignoreRedirect: boolean to skip redirect check
$target: Title/string of redirect target
$article: Article object

'InternalParseBeforeLinks': during Parser's internalParse method before links
but after nowiki/noinclude/includeonly/onlyinclude and other processings.
&$parser: Parser object
&$text: string containing partially parsed text
&$stripState: Parser's internal StripState object

'InternalParseBeforeSanitize': during Parser's internalParse method just before
the parser removes unwanted/dangerous HTML tags and after nowiki/noinclude/
includeonly/onlyinclude and other processings. Ideal for syntax-extensions after
template/parser function execution which respect nowiki and HTML-comments.
&$parser: Parser object
&$text: string containing partially parsed text
&$stripState: Parser's internal StripState object

'InterwikiLoadPrefix': When resolving if a given prefix is an interwiki or not.
Return true without providing an interwiki to continue interwiki search.
$prefix: interwiki prefix we are looking for.
&$iwData: output array describing the interwiki with keys iw_url, iw_local,
  iw_trans and optionally iw_api and iw_wikiid.

'InvalidateEmailComplete': Called after a user's email has been invalidated
successfully.
$user: user (object) whose email is being invalidated

'IRCLineURL': When constructing the URL to use in an IRC notification.
Callee may modify $url and $query, URL will be constructed as $url . $query
&$url: URL to index.php
&$query: Query string
$rc: RecentChange object that triggered url generation

'IsFileCacheable': Override the result of Article::isFileCacheable() (if true)
$article: article (object) being checked

'IsTrustedProxy': Override the result of wfIsTrustedProxy()
$ip: IP being check
$result: Change this value to override the result of wfIsTrustedProxy()

'IsUploadAllowedFromUrl': Override the result of UploadFromUrl::isAllowedUrl()
$url: URL used to upload from
&$allowed: Boolean indicating if uploading is allowed for given URL

'isValidEmailAddr': Override the result of Sanitizer::validateEmail(), for
instance to return false if the domain name doesn't match your organization.
$addr: The e-mail address entered by the user
&$result: Set this and return false to override the internal checks

'isValidPassword': Override the result of User::isValidPassword()
$password: The password entered by the user
&$result: Set this and return false to override the internal checks
$user: User the password is being validated for

'Language::getMessagesFileName':
$code: The language code or the language we're looking for a messages file for
&$file: The messages file path, you can override this to change the location.

'LanguageGetMagic': DEPRECATED! Use $magicWords in a file listed in
$wgExtensionMessagesFiles instead.
Use this to define synonyms of magic words depending of the language
$magicExtensions: associative array of magic words synonyms
$lang: language code (string)

'LanguageGetNamespaces': Provide custom ordering for namespaces or
remove namespaces. Do not use this hook to add namespaces. Use
CanonicalNamespaces for that.
&$namespaces: Array of namespaces indexed by their numbers

'LanguageGetSpecialPageAliases': DEPRECATED! Use $specialPageAliases in a file
listed in $wgExtensionMessagesFiles instead.
Use to define aliases of special pages names depending of the language
$specialPageAliases: associative array of magic words synonyms
$lang: language code (string)

'LanguageGetTranslatedLanguageNames': Provide translated language names.
&$names: array of language code => language name
$code: language of the preferred translations

'LanguageLinks': Manipulate a page's language links. This is called
in various places to allow extensions to define the effective language
links for a page.
$title: The page's Title.
&$links: Associative array mapping language codes to prefixed links of the
  form "language:title".
&$linkFlags: Associative array mapping prefixed links to arrays of flags.
  Currently unused, but planned to provide support for marking individual
  language links in the UI, e.g. for featured articles.

'LanguageSelector': Hook to change the language selector available on a page.
$out: The output page.
$cssClassName: CSS class name of the language selector.

'LinkBegin': Used when generating internal and interwiki links in
Linker::link(), before processing starts.  Return false to skip default
processing and return $ret. See documentation for Linker::link() for details on
the expected meanings of parameters.
$skin: the Skin object
$target: the Title that the link is pointing to
&$html: the contents that the <a> tag should have (raw HTML); null means
  "default".
&$customAttribs: the HTML attributes that the <a> tag should have, in
  associative array form, with keys and values unescaped.  Should be merged
  with default values, with a value of false meaning to suppress the
  attribute.
&$query: the query string to add to the generated URL (the bit after the "?"),
  in associative array form, with keys and values unescaped.
&$options: array of options.  Can include 'known', 'broken', 'noclasses'.
&$ret: the value to return if your hook returns false.

'LinkEnd': Used when generating internal and interwiki links in Linker::link(),
just before the function returns a value.  If you return true, an <a> element
with HTML attributes $attribs and contents $html will be returned.  If you
return false, $ret will be returned.
$skin: the Skin object
$target: the Title object that the link is pointing to
$options: the options.  Will always include either 'known' or 'broken', and may
  include 'noclasses'.
&$html: the final (raw HTML) contents of the <a> tag, after processing.
&$attribs: the final HTML attributes of the <a> tag, after processing, in
  associative array form.
&$ret: the value to return if your hook returns false.

'LinkerMakeExternalImage': At the end of Linker::makeExternalImage() just
before the return.
&$url: the image url
&$alt: the image's alt text
&$img: the new image HTML (if returning false)

'LinkerMakeExternalLink': At the end of Linker::makeExternalLink() just
before the return.
&$url: the link url
&$text: the link text
&$link: the new link HTML (if returning false)
&$attribs: the attributes to be applied.
$linkType: The external link type

'LinkerMakeMediaLinkFile': At the end of Linker::makeMediaLinkFile() just
before the return.
$title: the Title object that the link is pointing to
$file: the File object or false if broken link
&$html: the link text
&$attribs: the attributes to be applied
&$ret: the value to return if your hook returns false

'LinksUpdate': At the beginning of LinksUpdate::doUpdate() just before the
actual update.
&$linksUpdate: the LinksUpdate object

'LinksUpdateAfterInsert': At the end of LinksUpdate::incrTableUpdate() after
each link table insert.  For example, pagelinks, imagelinks, externallinks.
$linksUpdate: LinksUpdate object
$table: the table to insert links to
$insertions: an array of links to insert

'LinksUpdateComplete': At the end of LinksUpdate::doUpdate() when updating,
including delete and insert, has completed for all link tables
&$linksUpdate: the LinksUpdate object

'LinksUpdateConstructed': At the end of LinksUpdate() is construction.
&$linksUpdate: the LinksUpdate object

'ListDefinedTags': When trying to find all defined tags.
&$tags: The list of tags.

'LoadExtensionSchemaUpdates': Called during database installation and updates.
&$updater: A DatabaseUpdater subclass

'LocalFile::getHistory': Called before file history query performed.
$file: the File object
$tables: tables
$fields: select fields
$conds: conditions
$opts: query options
$join_conds: JOIN conditions

'LocalFilePurgeThumbnails': Called before thumbnails for a local file a purged.
$file: the File object
$archiveName: name of an old file version or false if it's the current one

'LocalisationCacheRecache': Called when loading the localisation data into
cache.
$cache: The LocalisationCache object
$code: language code
&$alldata: The localisation data from core and extensions
&$purgeBlobs: whether to purge/update the message blobs via
  MessageBlobStore::clear()

'LocalisationCacheRecacheFallback': Called for each language when merging
fallback data into the cache.
$cache: The LocalisationCache object
$code: language code
&$alldata: The localisation data from core and extensions. Note some keys may
  be omitted if they won't be merged into the final result.

'LocalisationChecksBlacklist': When fetching the blacklist of
localisation checks.
&$blacklist: array of checks to blacklist. See the bottom of
  maintenance/language/checkLanguage.inc for the format of this variable.

'LocalisationIgnoredOptionalMessages': When fetching the list of ignored and
optional localisation messages
&$ignored: Array of ignored message keys
&$optional: Array of optional message keys

'LocalUserCreated': Called when a local user has been created
$user: User object for the created user
$autocreated: Boolean, whether this was an auto-creation

'LogEventsListGetExtraInputs': When getting extra inputs to display on
Special:Log for a specific log type
$type: String of log type being displayed
$logEventsList: LogEventsList object for context and access to the WebRequest
&$input: string HTML of an input element

'LogEventsListShowLogExtract': Called before the string is added to OutputPage.
Returning false will prevent the string from being added to the OutputPage.
&$s: html string to show for the log extract
$types: String or Array Log types to show
$page: String or Title The page title to show log entries for
$user: String The user who made the log entries
$param: Associative Array with the following additional options:
  - lim Integer Limit of items to show, default is 50
  - conds Array Extra conditions for the query (e.g. "log_action != 'revision'")
  - showIfEmpty boolean Set to false if you don't want any output in case the
    loglist is empty if set to true (default), "No matching items in log" is
    displayed if loglist is empty
  - msgKey Array If you want a nice box with a message, set this to the key of
    the message. First element is the message key, additional optional elements
    are parameters for the key that are processed with
    wfMessage()->params()->parseAsBlock()
  - offset Set to overwrite offset parameter in $wgRequest set to '' to unset
    offset
  - wrap String Wrap the message in html (usually something like
    "&lt;div ...>$1&lt;/div>").
  - flags Integer display flags (NO_ACTION_LINK,NO_EXTRA_USER_LINKS)

'LogException': Called before an exception (or PHP error) is logged. This is
meant for integration with external error aggregation services; returning false
will NOT prevent logging.
$e: The exception (in case of a plain old PHP error, a wrapping ErrorException)
$suppressed: true if the error was suppressed via
  error_reporting()/wfSuppressWarnings()

'LoginAuthenticateAudit': A login attempt for a valid user account either
succeeded or failed. No return data is accepted; this hook is for auditing only.
$user: the User object being authenticated against
$password: the password being submitted and found wanting
$retval: a LoginForm class constant with authenticateUserData() return
  value (SUCCESS, WRONG_PASS, etc.).

'LoginFormValidErrorMessages': Called in LoginForm when a function gets valid
error messages. Allows to add additional error messages (except messages already
in LoginForm::$validErrorMessages).
&$messages: Already added messages (inclusive messages from
  LoginForm::$validErrorMessages)

'LoginPasswordResetMessage': User is being requested to reset their password on
login. Use this hook to change the Message that will be output on
Special:ChangePassword.
&$msg: Message object that will be shown to the user
$username: Username of the user who's password was expired.

'LoginUserMigrated': Called during login to allow extensions the opportunity to
inform a user that their username doesn't exist for a specific reason, instead
of letting the login form give the generic error message that the account does
not exist. For example, when the account has been renamed or deleted.
$user: the User object being authenticated against.
&$msg: the message identifier for abort reason, or an array to pass a message
  key and parameters.

'LogLine': Processes a single log entry on Special:Log.
$log_type: string for the type of log entry (e.g. 'move'). Corresponds to
  logging.log_type database field.
$log_action: string for the type of log action (e.g. 'delete', 'block',
  'create2'). Corresponds to logging.log_action database field.
$title: Title object that corresponds to logging.log_namespace and
  logging.log_title database fields.
$paramArray: Array of parameters that corresponds to logging.log_params field.
  Note that only $paramArray[0] appears to contain anything.
&$comment: string that corresponds to logging.log_comment database field, and
  which is displayed in the UI.
&$revert: string that is displayed in the UI, similar to $comment.
$time: timestamp of the log entry (added in 1.12)

'LonelyPagesQuery': Allow extensions to modify the query used by
Special:LonelyPages.
&$tables: tables to join in the query
&$conds: conditions for the query
&$joinConds: join conditions for the query

'MagicWordwgVariableIDs': When defining new magic words IDs.
$variableIDs: array of strings

'MaintenanceRefreshLinksInit': before executing the refreshLinks.php maintenance
script.
$refreshLinks: RefreshLinks object

'MakeGlobalVariablesScript': Called at end of OutputPage::getJSVars.
Ideally, this hook should only be used to add variables that depend on
the current page/request; static configuration should be added through
ResourceLoaderGetConfigVars instead.
&$vars: variable (or multiple variables) to be added into the output of
  Skin::makeVariablesScript
$out: The OutputPage which called the hook, can be used to get the real title.

'MarkPatrolled': Before an edit is marked patrolled.
$rcid: ID of the revision to be marked patrolled
$user: the user (object) marking the revision as patrolled
$wcOnlySysopsCanPatrol: config setting indicating whether the user needs to be a
  sysop in order to mark an edit patrolled.

'MarkPatrolledComplete': After an edit is marked patrolled.
$rcid: ID of the revision marked as patrolled
$user: user (object) who marked the edit patrolled
$wcOnlySysopsCanPatrol: config setting indicating whether the user must be a
  sysop to patrol the edit.

'MediaWikiPerformAction': Override MediaWiki::performAction(). Use this to do
something completely different, after the basic globals have been set up, but
before ordinary actions take place.
$output: $wgOut
$article: Article on which the action will be performed
$title: Title on which the action will be performed
$user: $wgUser
$request: $wgRequest
$mediaWiki: The $mediawiki object

'MessageCache::get': When fetching a message. Can be used to override the key
for customisations. Given and returned message key must be in special format:
1) first letter must be in lower case according to the content language.
2) spaces must be replaced with underscores
&$key: message key (string)

'MessageCacheReplace': When a message page is changed. Useful for updating
caches.
$title: name of the page changed.
$text: new contents of the page.

'MessagesPreLoad': When loading a message from the database.
$title: title of the message (string)
$message: value (string), change it to the message you want to define

'MimeMagicGuessFromContent': Allows MW extensions guess the MIME by content.
$mimeMagic: Instance of MimeMagic.
&$head: First 1024 bytes of the file in a string (in - Do not alter!).
&$tail: More or equal than last 65558 bytes of the file in a string
  (in - Do not alter!).
$file: File path.
&$mime: MIME type (out).

'MimeMagicImproveFromExtension': Allows MW extensions to further improve the
MIME type detected by considering the file extension.
$mimeMagic: Instance of MimeMagic.
$ext: File extension.
&$mime: MIME type (in/out).

'MimeMagicInit': Before processing the list mapping MIME types to media types
and the list mapping MIME types to file extensions.
As an extension author, you are encouraged to submit patches to MediaWiki's
core to add new MIME types to mime.types.
$mimeMagic: Instance of MimeMagic.
  Use $mimeMagic->addExtraInfo( $stringOfInfo );
  for adding new MIME info to the list.
  Use $mimeMagic->addExtraTypes( $stringOfTypes );
  for adding new MIME types to the list.

'ModifyExportQuery': Modify the query used by the exporter.
$db: The database object to be queried.
&$tables: Tables in the query.
&$conds: Conditions in the query.
&$opts: Options for the query.
&$join_conds: Join conditions for the query.

'MovePageCheckPermissions': Specify whether the user is allowed to move the
page.
$oldTitle: Title object of the current (old) location
$newTitle: Title object of the new location
$user: User making the move
$reason: string of the reason provided by the user
$status: Status object to pass error messages to

'MovePageIsValidMove': Specify whether a page can be moved for technical
reasons.
$oldTitle: Title object of the current (old) location
$newTitle: Title object of the new location
$status: Status object to pass error messages to

'NamespaceIsMovable': Called when determining if it is possible to pages in a
namespace.
$index: Integer; the index of the namespace being checked.
$result: Boolean; whether MediaWiki currently thinks that pages in this
  namespace are movable. Hooks may change this value to override the return
  value of MWNamespace::isMovable().

'NewDifferenceEngine': Called when a new DifferenceEngine object is made
$title: the diff page title (nullable)
&$oldId: the actual old Id to use in the diff
&$newId: the actual new Id to use in the diff (0 means current)
$old: the ?old= param value from the url
$new: the ?new= param value from the url

'NewRevisionFromEditComplete': Called when a revision was inserted due to an
edit.
$wikiPage: the WikiPage edited
$rev: the new revision
$baseID: the revision ID this was based off, if any
$user: the editing user

'NormalizeMessageKey': Called before the software gets the text of a message
(stuff in the MediaWiki: namespace), useful for changing WHAT message gets
displayed.
&$key: the message being looked up. Change this to something else to change
  what message gets displayed (string)
&$useDB: whether or not to look up the message in the database (bool)
&$langCode: the language code to get the message for (string) - or -
  whether to use the content language (true) or site language (false) (bool)
&$transform: whether or not to expand variables and templates
  in the message (bool)

'OldChangesListRecentChangesLine': Customize entire recent changes line, or
return false to omit the line from RecentChanges and Watchlist special pages.
&$changeslist: The OldChangesList instance.
&$s: HTML of the form "<li>...</li>" containing one RC entry.
&$rc: The RecentChange object.
&$classes: array of css classes for the <li> element

'OpenSearchUrls': Called when constructing the OpenSearch description XML. Hooks
can alter or append to the array of URLs for search & suggestion formats.
&$urls: array of associative arrays with Url element attributes

'OpportunisticLinksUpdate': Called by WikiPage::triggerOpportunisticLinksUpdate
when a page view triggers a re-rendering of the page. This may happen
particularly if the parser cache is split by user language, and no cached
rendering of the page exists in the user's language. The hook is called
before checking whether page_links_updated indicates that the links are up
to date. Returning false will cause triggerOpportunisticLinksUpdate() to abort
without triggering any updates.
$page: the Page that was rendered.
$title: the Title of the rendered page.
$parserOutput: ParserOutput resulting from rendering the page.

'OtherBlockLogLink': Get links to the block log from extensions which blocks
users and/or IP addresses too.
$otherBlockLink: An array with links to other block logs
$ip: The requested IP address or username

'OutputPageBeforeHTML': A page has been processed by the parser and the
resulting HTML is about to be displayed.
$parserOutput: the parserOutput (object) that corresponds to the page
$text: the text that will be displayed, in HTML (string)

'OutputPageBodyAttributes': Called when OutputPage::headElement is creating the
body tag to allow for extensions to add attributes to the body of the page they
might need. Or to allow building extensions to add body classes that aren't of
high enough demand to be included in core.
$out: The OutputPage which called the hook, can be used to get the real title
$sk: The Skin that called OutputPage::headElement
&$bodyAttrs: An array of attributes for the body tag passed to Html::openElement

'OutputPageCheckLastModified': when checking if the page has been modified
since the last visit.
&$modifiedTimes: array of timestamps.
  The following keys are set: page, user, epoch

'OutputPageMakeCategoryLinks': Links are about to be generated for the page's
categories. Implementations should return false if they generate the category
links, so the default link generation is skipped.
$out: OutputPage instance (object)
$categories: associative array, keys are category names, values are category
  types ("normal" or "hidden")
$links: array, intended to hold the result. Must be an associative array with
  category types as keys and arrays of HTML links as values.

'OutputPageParserOutput': after adding a parserOutput to $wgOut
$out: OutputPage instance (object)
$parserOutput: parserOutput instance being added in $out

'PageContentInsertComplete': After a new article is created.
$wikiPage: WikiPage created
$user: User creating the article
$content: New content as a Content object
$summary: Edit summary/comment
$isMinor: Whether or not the edit was marked as minor
$isWatch: (No longer used)
$section: (No longer used)
$flags: Flags passed to WikiPage::doEditContent()
$revision: New Revision of the article

'PageContentLanguage': Allows changing the language in which the content of a
page is written. Defaults to the wiki content language ($wgContLang).
$title: Title object
&$pageLang: the page content language (either an object or a language code)
$wgLang: the user language

'PageContentSave': Before an article is saved.
$wikiPage: the WikiPage (object) being saved
$user: the user (object) saving the article
$content: the new article content, as a Content object
$summary: the article summary (comment)
$isminor: minor flag
$iswatch: watch flag
$section: section #

'PageContentSaveComplete': After an article has been updated.
$wikiPage: WikiPage modified
$user: User performing the modification
$content: New content, as a Content object
$summary: Edit summary/comment
$isMinor: Whether or not the edit was marked as minor
$isWatch: (No longer used)
$section: (No longer used)
$flags: Flags passed to WikiPage::doEditContent()
$revision: New Revision of the article (can be null for edits that change
  nothing)
$status: Status object about to be returned by doEditContent()
$baseRevId: the rev ID (or false) this edit was based on

'PageHistoryBeforeList': When a history page list is about to be constructed.
$article: the article that the history is loading for
$context: RequestContext object

'PageHistoryLineEnding': Right before the end <li> is added to a history line.
$row: the revision row for this line
$s: the string representing this parsed line
$classes: array containing the <li> element classes

'PageHistoryPager::doBatchLookups': Called after the pager query was run, before
any output is generated, to allow batch lookups for prefetching information
needed for display. If the hook handler returns false, the regular behavior of
doBatchLookups() is skipped.
$pager: the PageHistoryPager
$result: a ResultWrapper representing the query result

'PageHistoryPager::getQueryInfo': when a history pager query parameter set is
constructed.
$pager: the pager
$queryInfo: the query parameters

'PageRenderingHash': Alter the parser cache option hash key. A parser extension
which depends on user options should install this hook and append its values to
the key.
&$confstr: reference to a hash key string which can be modified
$user: User (object) requesting the page

'PageViewUpdates': Allow database (or other) changes to be made after a
page view is seen by MediaWiki.  Note this does not capture views made
via external caches such as Squid.
$wikipage: WikiPage (object) for the page being viewed.
$user: User (object) for the user who is viewing.

'ParserAfterParse': Called from Parser::parse() just after the call to
Parser::internalParse() returns.
$parser: parser object
$text: text being parsed
$stripState: stripState used (object)

'ParserAfterStrip': Called at end of parsing time.
TODO: No more strip, deprecated ?
$parser: parser object
$text: text being parsed
$stripState: stripState used (object)

'ParserAfterTidy': Called after Parser::tidy() in Parser::parse()
$parser: Parser object being used
$text: text that will be returned

'ParserAfterUnstrip': Called after the first unstripGeneral() in
Parser::internalParseHalfParsed()
$parser: Parser object being used
$text: text that will be returned

'ParserBeforeInternalParse': Called at the beginning of Parser::internalParse().
$parser: Parser object
$text: text to parse
$stripState: StripState instance being used

'ParserBeforeStrip': Called at start of parsing time.
TODO: No more strip, deprecated ?
$parser: parser object
$text: text being parsed
$stripState: stripState used (object)

'ParserBeforeTidy': Called before tidy and custom tags replacements.
$parser: Parser object being used
$text: actual text

'ParserCacheSaveComplete': Called after a ParserOutput has been committed to
the parser cache.
$parserCache: ParserCache object $parserOutput was stored in
$parserOutput: ParserOutput object that was stored
$title: Title of the page that was parsed to generate $parserOutput
$popts: ParserOptions used for generating $parserOutput
$revId: ID of the revision that was parsed to create $parserOutput

'ParserClearState': Called at the end of Parser::clearState().
$parser: Parser object being cleared

'ParserCloned': Called when the parser is cloned.
$parser: Newly-cloned Parser object

'ParserFirstCallInit': Called when the parser initialises for the first time.
&$parser: Parser object being cleared

'ParserGetVariableValueSwitch': Called when the parser need the value of a
custom magic word
$parser: Parser object
$varCache: array to store the value in case of multiples calls of the
  same magic word
$index: index (string) of the magic
$ret: value of the magic word (the hook should set it)
$frame: PPFrame object to use for expanding any template variables

'ParserGetVariableValueTs': Use this to change the value of the time for the
{{LOCAL...}} magic word.
$parser: Parser object
$time: actual time (timestamp)

'ParserGetVariableValueVarCache': use this to change the value of the variable
cache or return false to not use it.
$parser: Parser object
$varCache: variable cache (array)

'ParserLimitReport': DEPRECATED! Use ParserLimitReportPrepare and
ParserLimitReportFormat instead.
Called at the end of Parser:parse() when the parser will
include comments about size of the text parsed.
$parser: Parser object
&$limitReport: text that will be included (without comment tags)

'ParserLimitReportFormat': Called for each row in the parser limit report that
needs formatting. If nothing handles this hook, the default is to use "$key" to
get the label, and "$key-value" or "$key-value-text"/"$key-value-html" to
format the value.
$key: Key for the limit report item (string)
&$value: Value of the limit report item
&$report: String onto which to append the data
$isHTML: If true, $report is an HTML table with two columns; if false, it's
  text intended for display in a monospaced font.
$localize: If false, $report should be output in English.

'ParserLimitReportPrepare': Called at the end of Parser:parse() when the parser
will include comments about size of the text parsed. Hooks should use
$output->setLimitReportData() to populate data. Functions for this hook should
not use $wgLang; do that in ParserLimitReportFormat instead.
$parser: Parser object
$output: ParserOutput object

'ParserMakeImageParams': Called before the parser make an image link, use this
to modify the parameters of the image.
$title: title object representing the file
$file: file object that will be used to create the image
&$params: 2-D array of parameters
$parser: Parser object that called the hook

'ParserSectionCreate': Called each time the parser creates a document section
from wikitext. Use this to apply per-section modifications to HTML (like
wrapping the section in a DIV).  Caveat: DIVs are valid wikitext, and a DIV
can begin in one section and end in another. Make sure your code can handle
that case gracefully. See the EditSectionClearerLink extension for an example.
$parser: the calling Parser instance
$section: the section number, zero-based, but section 0 is usually empty
&$sectionContent: ref to the content of the section. modify this.
$showEditLinks: boolean describing whether this section has an edit link

'ParserTestGlobals': Allows to define globals for parser tests.
&$globals: Array with all the globals which should be set for parser tests.
  The arrays keys serve as the globals names, its values are the globals values.

'ParserTestParser': Called when creating a new instance of Parser in
tests/parser/parserTest.inc.
$parser: Parser object created

'ParserTestTables': Alter the list of tables to duplicate when parser tests are
run. Use when page save hooks require the presence of custom tables to ensure
that tests continue to run properly.
&$tables: array of table names

'PasswordPoliciesForUser': Alter the effective password policy for a user.
$user: User object whose policy you are modifying
&$effectivePolicy: Array of policy statements that apply to this user
$purpose: string indicating purpose of the check, one of 'login', 'create',
  or 'reset'

'PerformRetroactiveAutoblock': Called before a retroactive autoblock is applied
to a user.
$block: Block object (which is set to be autoblocking)
&$blockIds: Array of block IDs of the autoblock

'PersonalUrls': Alter the user-specific navigation links (e.g. "my page,
my talk page, my contributions" etc).
&$personal_urls: Array of link specifiers (see SkinTemplate.php)
&$title: Title object representing the current page
$skin: SkinTemplate object providing context (e.g. to check if the user is
  logged in, etc.)

'PingLimiter': Allows extensions to override the results of User::pingLimiter().
&$user: User performing the action
$action: Action being performed
&$result: Whether or not the action should be prevented
  Change $result and return false to give a definitive answer, otherwise
  the built-in rate limiting checks are used, if enabled.
$incrBy: Amount to increment counter by

'PlaceNewSection': Override placement of new sections. Return false and put the
merged text into $text to override the default behavior.
$wikipage: WikiPage object
$oldtext: the text of the article before editing
$subject: subject of the new section
&$text: text of the new section

'PostLoginRedirect': Modify the post login redirect behavior.
Occurs after signing up or logging in, allows for interception of redirect.
&$returnTo: The page name to return to, as a string
&$returnToQuery: array of url parameters, mapping parameter names to values
&$type: type of login redirect as string;
  error: display a return to link ignoring $wgRedirectOnLogin
  signup: display a return to link using $wgRedirectOnLogin if needed
  success: display a return to link using $wgRedirectOnLogin if needed
  successredirect: send an HTTP redirect using $wgRedirectOnLogin if needed

'PreferencesFormPreSave': Override preferences being saved
$formData: array of user submitted data
$form: PreferencesForm object, also a ContextSource
$user: User object with preferences to be saved set
&$result: boolean indicating success

'PreferencesGetLegend': Override the text used for the <legend> of a
preferences section.
$form: the PreferencesForm object. This is a ContextSource as well
$key: the section name
&$legend: the legend text. Defaults to wfMessage( "prefs-$key" )->text() but may
  be overridden

'PrefixSearchBackend': Override the title prefix search used for OpenSearch and
AJAX search suggestions. Put results into &$results outparam and return false.
$ns: array of int namespace keys to search in
$search: search term (not guaranteed to be conveniently normalized)
$limit: maximum number of results to return
&$results: out param: array of page names (strings)
$offset: number of results to offset from the beginning

'PrefixSearchExtractNamespace': Called if core was not able to extract a
namespace from the search string so that extensions can attempt it.
$namespaces: array of int namespace keys to search in (change this if you can
  extract namespaces)
$search: search term (replace this with term without the namespace if you can
  extract one)

'PrefsEmailAudit': Called when user changes their email address.
$user: User (object) changing his email address
$oldaddr: old email address (string)
$newaddr: new email address (string)

'PrefsPasswordAudit': Called when user changes his password.
$user: User (object) changing his password
$newPass: new password
$error: error (string) 'badretype', 'wrongpassword', 'error' or 'success'

'ProtectionForm::buildForm': Called after all protection type fieldsets are made
in the form.
$article: the title being (un)protected
$output: a string of the form HTML so far

'ProtectionForm::save': Called when a protection form is submitted.
$article: the Page being (un)protected
&$errorMsg: an html message string of an error or an array of message name and
  its parameters
$reasonstr: a string describing the reason page protection level is altered

'ProtectionForm::showLogExtract': Called after the protection log extract is
shown.
$article: the page the form is shown for
$out: OutputPage object

'RandomPageQuery': Lets you modify the query used by Special:Random to select
random pages.
&$tables: Database tables to be used in the query
&$conds: Conditions to be applied in the query
&$joinConds: Join conditions to be applied in the query

'RawPageViewBeforeOutput': Right before the text is blown out in action=raw.
&$obj: RawAction object
&$text: The text that's going to be the output

'RecentChange_save': Called at the end of RecentChange::save().
$recentChange: RecentChange object

'RedirectSpecialArticleRedirectParams': Lets you alter the set of parameter
names such as "oldid" that are preserved when using redirecting special pages
such as Special:MyPage and Special:MyTalk.
&$redirectParams: An array of parameters preserved by redirecting special pages.

'RejectParserCacheValue': Return false to reject an otherwise usable
cached value from the Parser cache. NOTE: CARELESS USE OF THIS HOOK CAN
HAVE CATASTROPHIC CONSEQUENCES FOR HIGH-TRAFFIC INSTALLATIONS. USE WITH
EXTREME CARE.
$parserOutput: ParserOutput value.
$wikiPage: WikiPage object.
$parserOptions: ParserOptions object.

'RequestContextCreateSkin': Called when RequestContext::getSkin creates a skin
instance. Can be used by an extension override what skin is used in certain
contexts.
$context: (IContextSource) The RequestContext the skin is being created for.
&$skin: A variable reference you may set a Skin instance or string key on to
  override the skin that will be used for the context.

'ResetPasswordExpiration': Allow extensions to set a default password expiration
$user: The user having their password expiration reset
&$newExpire: The new expiration date

'ResourceLoaderForeignApiModules': Called from ResourceLoaderForeignApiModule.
Use this to add dependencies to 'mediawiki.ForeignApi' module when you wish
to override its behavior. See the module docs for more information.
&$dependencies: string[] List of modules that 'mediawiki.ForeignApi' should
depend on
$context: ResourceLoaderContext|null

'ResourceLoaderGetConfigVars': Called at the end of
ResourceLoaderStartUpModule::getConfigSettings(). Use this to export static
configuration variables to JavaScript. Things that depend on the current page
or request state must be added through MakeGlobalVariablesScript instead.
&$vars: array( variable name => value )

'ResourceLoaderGetLessVars': Called in ResourceLoader::getLessVars after
variables from $wgResourceLoaderLESSVars are added. Can be used to add
context-based variables.
&$lessVars: array of variables already added

'ResourceLoaderRegisterModules': Right before modules information is required,
such as when responding to a resource
loader request or generating HTML output.
&$resourceLoader: ResourceLoader object

'ResourceLoaderTestModules': Let you add new JavaScript testing modules. This is
called after the addition of 'qunit' and MediaWiki testing resources.
&$testModules: array of JavaScript testing modules. The 'qunit' framework,
  included in core, is fed using tests/qunit/QUnitTestResources.php.
  To add a new qunit module named 'myext.tests':
	$testModules['qunit']['myext.tests'] = array(
		'script' => 'extension/myext/tests.js',
		'dependencies' => <any module dependency you might have>
	);
  For QUnit framework, the mediawiki.tests.qunit.testrunner dependency will be
  added to any module.
&$ResourceLoader: object

'RevisionInsertComplete': Called after a revision is inserted into the database.
&$revision: the Revision
$data: the data stored in old_text.  The meaning depends on $flags: if external
  is set, it's the URL of the revision text in external storage; otherwise,
  it's the revision text itself.  In either case, if gzip is set, the revision
  text is gzipped.
$flags: a comma-delimited list of strings representing the options used.  May
  include: utf8 (this will always be set for new revisions); gzip; external.

'SearchableNamespaces': An option to modify which namespaces are searchable.
&$arr: Array of namespaces ($nsId => $name) which will be used.

'SearchAfterNoDirectMatch': If there was no match for the exact result. This
runs before lettercase variants are attempted, whereas 'SearchGetNearMatch'
runs after.
$term: Search term string
&$title: Outparam; set to $title object and return false for a match

'SearchGetNearMatch': An extra chance for exact-title-matches in "go" searches
if nothing was found.
$term: Search term string
&$title: Outparam; set to $title object and return false for a match

'SearchGetNearMatchBefore': Perform exact-title-matches in "go" searches before
the normal operations.
$allSearchTerms: Array of the search terms in all content languages
&$titleResult: Outparam; the value to return. A Title object or null.

'SearchGetNearMatchComplete': A chance to modify exact-title-matches in "go"
searches.
$term: Search term string
&$title: Current Title object that is being returned (null if none found).

'SearchResultInitFromTitle': Set the revision used when displaying a page in
search results.
$title: Current Title object being displayed in search results.
&$id: Revision ID (default is false, for latest)

'SecondaryDataUpdates': Allows modification of the list of DataUpdates to
perform when page content is modified. Currently called by
AbstractContent::getSecondaryDataUpdates.
$title: Title of the page that is being edited.
$oldContent: Content object representing the page's content before the edit.
$recursive: bool indicating whether DataUpdates should trigger recursive
  updates (relevant mostly for LinksUpdate).
$parserOutput: ParserOutput representing the rendered version of the page
  after the edit.
&$updates: a list of DataUpdate objects, to be modified or replaced by
  the hook handler.

'SelfLinkBegin': Called before a link to the current article is displayed to
allow the display of the link to be customized.
$nt: the Title object
&$html: html to display for the link
&$trail: optional text to display before $html
&$prefix: optional text to display after $html
&$ret: the value to return if your hook returns false

'SendWatchlistEmailNotification': Return true to send watchlist email
notification
$targetUser: the user whom to send watchlist email notification
$title: the page title
$enotif: EmailNotification object

'SetupAfterCache': Called in Setup.php, after cache objects are set

'ShowMissingArticle': Called when generating the output for a non-existent page.
$article: The article object corresponding to the page

'ShowRawCssJs': DEPRECATED! Use the ContentGetParserOutput hook instead.
Customise the output of raw CSS and JavaScript in page views.
$text: Text being shown
$title: Title of the custom script/stylesheet page
$output: Current OutputPage object

'ShowSearchHit': Customize display of search hit.
$searchPage: The SpecialSearch instance.
$result: The SearchResult to show
$terms: Search terms, for highlighting
&$link: HTML of link to the matching page. May be modified.
&$redirect: HTML of redirect info. May be modified.
&$section: HTML of matching section. May be modified.
&$extract: HTML of content extract. May be modified.
&$score: HTML of score. May be modified.
&$size: HTML of page size. May be modified.
&$date: HTML of of page modification date. May be modified.
&$related: HTML of additional info for the matching page. May be modified.
&$html: May be set to the full HTML that should be used to represent the search
  hit. Must include the <li> ... </li> tags. Will only be used if the hook
  function returned false.

'ShowSearchHitTitle': Customise display of search hit title/link.
&$title: Title to link to
&$text: Text to use for the link
$result: The search result
$terms: The search terms entered
$page: The SpecialSearch object.

'SidebarBeforeOutput': Allows to edit sidebar just before it is output by skins.
Warning: This hook is run on each display. You should consider to use
'SkinBuildSidebar' that is aggressively cached.
$skin: Skin object
&$bar: Sidebar content
  Modify $bar to add or modify sidebar portlets.

'SiteNoticeAfter': After the sitenotice/anonnotice is composed.
&$siteNotice: HTML sitenotice. Alter the contents of $siteNotice to add to/alter
  the sitenotice/anonnotice.
$skin: Skin object

'SiteNoticeBefore': Before the sitenotice/anonnotice is composed. Return true to
allow the normal method of notice selection/rendering to work, or change the
value of $siteNotice and return false to alter it.
&$siteNotice: HTML returned as the sitenotice
$skin: Skin object

'SkinAfterBottomScripts': At the end of Skin::bottomScripts().
$skin: Skin object
&$text: bottomScripts Text. Append to $text to add additional text/scripts after
  the stock bottom scripts.

'SkinAfterContent': Allows extensions to add text after the page content and
article metadata. This hook should work in all skins. Set the &$data variable to
the text you're going to add.
&$data: (string) Text to be printed out directly (without parsing)
$skin: Skin object

'SkinBuildSidebar': At the end of Skin::buildSidebar().
$skin: Skin object
&$bar: Sidebar contents
Modify $bar to add or modify sidebar portlets.

'SkinCopyrightFooter': Allow for site and per-namespace customization of
copyright notice.
$title: displayed page title
$type: 'normal' or 'history' for old/diff views
&$msg: overridable message; usually 'copyright' or 'history_copyright'. This
  message must be in HTML format, not wikitext!
&$link: overridable HTML link to be passed into the message as $1
&$forContent: DEPRECATED! overridable flag if copyright footer is shown in
  content language.

'SkinEditSectionLinks': Modify the section edit links
$skin: Skin object rendering the UI
$title: Title object for the title being linked to (may not be the same as
  the page title, if the section is included from a template)
$section: The designation of the section being pointed to, to be included in
  the link, like "&section=$section"
$tooltip: The default tooltip.  Escape before using.
  By default, this is wrapped in the 'editsectionhint' message.
&$result: Array containing all link detail arrays. Each link detail array should
  contain the following keys:
    - targetTitle - Target Title object
    - text - String for the text
    - attribs - Array of attributes
    - query - Array of query parameters to add to the URL
    - options - Array of options for Linker::link
$lang: The language code to use for the link in the wfMessage function

'SkinGetPoweredBy': TODO
&$text: additional 'powered by' icons in HTML. Note: Modern skin does not use
  the MediaWiki icon but plain text instead.
$skin: Skin object

'SkinPreloadExistence': Supply titles that should be added to link existence
cache before the page is rendered.
&$titles: Array of Title objects
$skin: Skin object

'SkinSubPageSubtitle': At the beginning of Skin::subPageSubtitle().
If false is returned $subpages will be used instead of the HTML
subPageSubtitle() generates.
If true is returned, $subpages will be ignored and the rest of
subPageSubtitle() will run.
&$subpages: Subpage links HTML
$skin: Skin object
$out: OutputPage object

'SkinTemplateBuildNavUrlsNav_urlsAfterPermalink': After creating the "permanent
link" tab.
$sktemplate: SkinTemplate object
$nav_urls: array of tabs

'SkinTemplateGetLanguageLink': After building the data for a language link from
which the actual html is constructed.
&$languageLink: array containing data about the link. The following keys can be
  modified: href, text, title, class, lang, hreflang. Each of them is a string.
$languageLinkTitle: Title object belonging to the external language link.
$title: Title object of the page the link belongs to.
$outputPage: The OutputPage object the links are built from.

'SkinTemplateNavigation': Called on content pages after the tabs have been
added, but before variants have been added.
&$sktemplate: SkinTemplate object
&$links: Structured navigation links. This is used to alter the navigation for
  skins which use buildNavigationUrls such as Vector.

'SkinTemplateNavigation::SpecialPage': Called on special pages after the special
tab is added but before variants have been added.
&$sktemplate: SkinTemplate object
&$links: Structured navigation links. This is used to alter the navigation for
  skins which use buildNavigationUrls such as Vector.

'SkinTemplateNavigation::Universal': Called on both content and special pages
after variants have been added.
&$sktemplate: SkinTemplate object
&$links: Structured navigation links. This is used to alter the navigation for
  skins which use buildNavigationUrls such as Vector.

'SkinTemplateOutputPageBeforeExec': Before SkinTemplate::outputPage() starts
page output.
&$sktemplate: SkinTemplate object
&$tpl: QuickTemplate engine object

'SkinTemplatePreventOtherActiveTabs': Use this to prevent showing active tabs.
$sktemplate: SkinTemplate object
$res: set to true to prevent active tabs

'SkinTemplateTabAction': Override SkinTemplate::tabAction().
You can either create your own array, or alter the parameters for
the normal one.
&$sktemplate: The SkinTemplate instance.
$title: Title instance for the page.
$message: Visible label of tab.
$selected: Whether this is a selected tab.
$checkEdit: Whether or not the action=edit query should be added if appropriate.
&$classes: Array of CSS classes to apply.
&$query: Query string to add to link.
&$text: Link text.
&$result: Complete assoc. array if you want to return true.

'SkinTemplateToolboxEnd': Called by SkinTemplate skins after toolbox links have
been rendered (useful for adding more).
$sk: The QuickTemplate based skin template running the hook.
$dummy: Called when SkinTemplateToolboxEnd is used from a BaseTemplate skin,
  extensions that add support for BaseTemplateToolbox should watch for this
  dummy parameter with "$dummy=false" in their code and return without echoing
  any HTML to avoid creating duplicate toolbox items.

'SoftwareInfo': Called by Special:Version for returning information about the
software.
$software: The array of software in format 'name' => 'version'. See
  SpecialVersion::softwareInformation().

'SpecialBlockModifyFormFields': Add more fields to Special:Block
$sp: SpecialPage object, for context
&$fields: Current HTMLForm fields

'SpecialContributionsBeforeMainOutput': Before the form on Special:Contributions
$id: User id number, only provided for backwards-compatibility
$user: User object representing user contributions are being fetched for
$sp: SpecialPage instance, providing context

'SpecialListusersDefaultQuery': Called right before the end of
UsersPager::getDefaultQuery().
$pager: The UsersPager instance
$query: The query array to be returned

'SpecialListusersFormatRow': Called right before the end of
UsersPager::formatRow().
$item: HTML to be returned. Will be wrapped in <li></li> after the hook finishes
$row: Database row object

'SpecialListusersHeader': Called before closing the <fieldset> in
UsersPager::getPageHeader().
$pager: The UsersPager instance
$out: The header HTML

'SpecialListusersHeaderForm': Called before adding the submit button in
UsersPager::getPageHeader().
$pager: The UsersPager instance
$out: The header HTML

'SpecialListusersQueryInfo': Called right before the end of.
UsersPager::getQueryInfo()
$pager: The UsersPager instance
$query: The query array to be returned

'SpecialLogAddLogSearchRelations': Add log relations to the current log
$type: String of the log type
$request: WebRequest object for getting the value provided by the current user
&$qc: Array for query conditions to add

'SpecialMovepageAfterMove': Called after moving a page.
$movePage: MovePageForm object
$oldTitle: old title (object)
$newTitle: new title (object)

'SpecialNewpagesConditions': Called when building sql query for
Special:NewPages.
&$special: NewPagesPager object (subclass of ReverseChronologicalPager)
$opts: FormOptions object containing special page options
&$conds: array of WHERE conditionals for query
&$tables: array of tables to be queried
&$fields: array of columns to select
&$join_conds: join conditions for the tables

'SpecialNewPagesFilters': Called after building form options at NewPages.
$special: the special page object
&$filters: associative array of filter definitions. The keys are the HTML
  name/URL parameters. Each key maps to an associative array with a 'msg'
  (message key) and a 'default' value.

'SpecialPage_initList': Called when setting up SpecialPageFactory::$list, use
this hook to remove a core special page or conditionally register special pages.
$list: list (array) of core special pages

'SpecialPageAfterExecute': Called after SpecialPage::execute.
$special: the SpecialPage object
$subPage: the subpage string or null if no subpage was specified

'SpecialPageBeforeExecute': Called before SpecialPage::execute.
$special: the SpecialPage object
$subPage: the subpage string or null if no subpage was specified

'SpecialPageBeforeFormDisplay': Before executing the HTMLForm object.
$name: name of the special page
&$form: HTMLForm object

'SpecialPasswordResetOnSubmit': When executing a form submission on
Special:PasswordReset.
$users: array of User objects.
$data: array of data submitted by the user
&$error: string, error code (message key) used to describe to error (out
  parameter). The hook needs to return false when setting this, otherwise it
  will have no effect.

'SpecialRandomGetRandomTitle': Called during the execution of Special:Random,
use this to change some selection criteria or substitute a different title.
&$randstr: The random number from wfRandom()
&$isRedir: Boolean, whether to select a redirect or non-redirect
&$namespaces: An array of namespace indexes to get the title from
&$extra: An array of extra SQL statements
&$title: If the hook returns false, a Title object to use instead of the
  result from the normal query

'SpecialRecentChangesFilters': DEPRECATED! Use ChangesListSpecialPageFilters
instead.
Called after building form options at RecentChanges.
$special: the special page object
&$filters: associative array of filter definitions. The keys are the HTML
  name/URL parameters. Each key maps to an associative array with a 'msg'
  (message key) and a 'default' value.

'SpecialRecentChangesPanel': Called when building form options in
SpecialRecentChanges.
&$extraOpts: array of added items, to which can be added
$opts: FormOptions for this request

'SpecialRecentChangesQuery': DEPRECATED! Use ChangesListSpecialPageQuery
instead.
Called when building SQL query for SpecialRecentChanges and
SpecialRecentChangesLinked.
&$conds: array of WHERE conditionals for query
&$tables: array of tables to be queried
&$join_conds: join conditions for the tables
$opts: FormOptions for this request
&$query_options: array of options for the database request
&$select: Array of columns to select

'SpecialResetTokensTokens': Called when building token list for
SpecialResetTokens.
&$tokens: array of token information arrays in the format of
	array(
		'preference' => '<preference-name>',
		'label-message' => '<message-key>',
	)

'SpecialSearchCreateLink': Called when making the message to create a page or
go to the existing page.
$t: title object searched for
&$params: an array of the default message name and page title (as parameter)

'SpecialSearchNogomatch': Called when user clicked the "Go" button but the
target doesn't exist.
&$title: title object generated from the text entered by the user

'SpecialSearchPowerBox': The equivalent of SpecialSearchProfileForm for
the advanced form, a.k.a. power search box.
&$showSections: an array to add values with more options to
$term: the search term (not a title object)
$opts: an array of hidden options (containing 'redirs' and 'profile')

'SpecialSearchProfileForm': Allows modification of search profile forms.
$search: special page object
&$form: String: form html
$profile: String: current search profile
$term: String: search term
$opts: Array: key => value of hidden options for inclusion in custom forms

'SpecialSearchProfiles': Allows modification of search profiles.
&$profiles: profiles, which can be modified.

'SpecialSearchResults': Called before search result display
$term: string of search term
&$titleMatches: empty or SearchResultSet object
&$textMatches: empty or SearchResultSet object

'SpecialSearchResultsPrepend': Called immediately before returning HTML
on the search results page.  Useful for including an external search
provider.  To disable the output of MediaWiki search output, return
false.
$specialSearch: SpecialSearch object ($this)
$output: $wgOut
$term: Search term specified by the user

'SpecialSearchResultsAppend': Called immediately before returning HTML
on the search results page.  Useful for including a feedback link.
$specialSearch: SpecialSearch object ($this)
$output: $wgOut

'SpecialSearchSetupEngine': Allows passing custom data to search engine.
$search: SpecialSearch special page object
$profile: String: current search profile
$engine: the search engine

'SpecialStatsAddExtra': Add extra statistic at the end of Special:Statistics.
&$extraStats: Array to save the new stats
	$extraStats['<name of statistic>'] => <value>;
  <value> can be an array with the keys "name" and "number":
  "name" is the HTML to be displayed in the name column
  "number" is the number to be displayed.
  or, <value> can be the number to be displayed and <name> is the
  message key to use in the name column,
$context: IContextSource object

'SpecialUploadComplete': Called after successfully uploading a file from
Special:Upload.
$form: The SpecialUpload object

'SpecialVersionVersionUrl': Called when building the URL for Special:Version.
$wgVersion: Current $wgVersion for you to use
&$versionUrl: Raw url to link to (eg: release notes)

'SpecialWatchlistFilters': DEPRECATED! Use ChangesListSpecialPageFilters
instead.
Called after building form options at Watchlist.
$special: the special page object
&$filters: associative array of filter definitions. The keys are the HTML
  name/URL parameters. Each key maps to an associative array with a 'msg'
  (message key) and a 'default' value.

'SpecialWatchlistGetNonRevisionTypes': Called when building sql query for
SpecialWatchlist. Allows extensions to register custom values they have
inserted to rc_type so they can be returned as part of the watchlist.
&$nonRevisionTypes: array of values in the rc_type field of recentchanges table

'SpecialWatchlistQuery': DEPRECATED! Use ChangesListSpecialPageQuery instead.
Called when building sql query for SpecialWatchlist.
&$conds: array of WHERE conditionals for query
&$tables: array of tables to be queried
&$join_conds: join conditions for the tables
&$fields: array of query fields
$opts: A FormOptions object with watchlist options for the current request

'TestCanonicalRedirect': Called when about to force a redirect to a canonical
URL for a title when we have no other parameters on the URL. Gives a chance for
extensions that alter page view behavior radically to abort that redirect or
handle it manually.
$request: WebRequest
$title: Title of the currently found title obj
$output: OutputPage object

'ThumbnailBeforeProduceHTML': Called before an image HTML is about to be
rendered (by ThumbnailImage:toHtml method).
$thumbnail: the ThumbnailImage object
&$attribs: image attribute array
&$linkAttribs: image link attribute array

'TitleArrayFromResult': Called when creating an TitleArray object from a
database result.
&$titleArray: set this to an object to override the default object returned
$res: database result used to create the object

'TitleExists': Called when determining whether a page exists at a given title.
$title: The title being tested.
&$exists: Whether the title exists.

'TitleGetEditNotices': Allows extensions to add edit notices
$title: The Title object for the page the edit notices are for
$oldid: Revision ID that the edit notices are for (or 0 for latest)
&$notices: Array of notices. Keys are i18n message keys, values are
parseAsBlock()ed messages.

'TitleGetRestrictionTypes': Allows extensions to modify the types of protection
that can be applied.
$title: The title in question.
&$types: The types of protection available.

'TitleIsAlwaysKnown': Called when determining if a page exists. Allows
overriding default behavior for determining if a page exists. If $isKnown is
kept as null, regular checks happen. If it's a boolean, this value is returned
by the isKnown method.
$title: Title object that is being checked
&$isKnown: Boolean|null; whether MediaWiki currently thinks this page is known

'TitleIsCssOrJsPage': DEPRECATED! Use ContentHandlerDefaultModelFor instead.
Called when determining if a page is a CSS or JS page.
$title: Title object that is being checked
$result: Boolean; whether MediaWiki currently thinks this is a CSS/JS page.
  Hooks may change this value to override the return value of
  Title::isCssOrJsPage().

'TitleIsMovable': Called when determining if it is possible to move a page. Note
that this hook is not called for interwiki pages or pages in immovable
namespaces: for these, isMovable() always returns false.
$title: Title object that is being checked
$result: Boolean; whether MediaWiki currently thinks this page is movable.
  Hooks may change this value to override the return value of
  Title::isMovable().

'TitleIsWikitextPage': DEPRECATED! Use ContentHandlerDefaultModelFor instead.
Called when determining if a page is a wikitext or should
be handled by separate handler (via ArticleViewCustom).
$title: Title object that is being checked
$result: Boolean; whether MediaWiki currently thinks this is a wikitext page.
  Hooks may change this value to override the return value of
  Title::isWikitextPage()

'TitleMove': Before moving an article (title).
$old: old title
$nt: new title
$user: user who does the move

'TitleMoveComplete': After moving an article (title).
$old: old title
$nt: new title
$user: user who did the move
$pageid: database ID of the page that's been moved
$redirid: database ID of the created redirect
$reason: reason for the move

'TitleQuickPermissions': Called from Title::checkQuickPermissions to add to
or override the quick permissions check.
$title: The Title object being accessed
$user: The User performing the action
$action: Action being performed
&$errors: Array of errors
$doExpensiveQueries: Whether to do expensive DB queries
$short: Whether to return immediately on first error

'TitleReadWhitelist': Called at the end of read permissions checks, just before
adding the default error message if nothing allows the user to read the page. If
a handler wants a title to *not* be whitelisted, it should also return false.
$title: Title object being checked against
$user: Current user object
&$whitelisted: Boolean value of whether this title is whitelisted

'TitleSquidURLs': Called to determine which URLs to purge from HTTP caches.
$title: Title object to purge
&$urls: An array of URLs to purge from the caches, to be manipulated.

'UndeleteForm::showHistory': Called in UndeleteForm::showHistory, after a
PageArchive object has been created but before any further processing is done.
&$archive: PageArchive object
$title: Title object of the page that we're viewing

'UndeleteForm::showRevision': Called in UndeleteForm::showRevision, after a
PageArchive object has been created but before any further processing is done.
&$archive: PageArchive object
$title: Title object of the page that we're viewing

'UndeleteForm::undelete': Called un UndeleteForm::undelete, after checking that
the site is not in read-only mode, that the Title object is not null and after
a PageArchive object has been constructed but before performing any further
processing.
&$archive: PageArchive object
$title: Title object of the page that we're about to undelete

'UndeleteShowRevision': Called when showing a revision in Special:Undelete.
$title: title object related to the revision
$rev: revision (object) that will be viewed

'UnitTestsList': Called when building a list of paths containing PHPUnit tests.
Since 1.24: Paths pointing to a directory will be recursively scanned for
test case files matching the suffix "Test.php".
&$paths: list of test cases and directories to search.

'UnknownAction': An unknown "action" has occurred (useful for defining your own
actions).
$action: action name
$article: article "acted on"

'UnwatchArticle': Before a watch is removed from an article.
$user: user watching
$page: WikiPage object to be removed
&$status: Status object to be returned if the hook returns false

'UnwatchArticleComplete': After a watch is removed from an article.
$user: user that watched
$page: WikiPage object that was watched

'UpdateUserMailerFormattedPageStatus': Before notification email gets sent.
$formattedPageStatus: list of valid page states

'UploadComplete': Upon completion of a file upload.
$uploadBase: UploadBase (or subclass) object. File can be accessed by
  $uploadBase->getLocalFile().

'UploadCreateFromRequest': When UploadBase::createFromRequest has been called.
$type: (string) the requested upload type
&$className: the class name of the Upload instance to be created

'UploadForm:BeforeProcessing': At the beginning of processUpload(). Lets you
poke at member variables like $mUploadDescription before the file is saved. Do
not use this hook to break upload processing. This will return the user to a
blank form with no error message; use UploadVerification and UploadVerifyFile
instead.
$form: UploadForm object

'UploadForm:initial': Before the upload form is generated. You might set the
member-variables $uploadFormTextTop and $uploadFormTextAfterSummary to inject
text (HTML) either before or after the editform.
$form: UploadForm object

'UploadFormInitDescriptor': After the descriptor for the upload form as been
assembled.
$descriptor: (array) the HTMLForm descriptor

'UploadFormSourceDescriptors': after the standard source inputs have been
added to the descriptor
$descriptor: (array) the HTMLForm descriptor

'UploadVerification': Additional chances to reject an uploaded file. Consider
using UploadVerifyFile instead.
$saveName: (string) destination file name
$tempName: (string) filesystem path to the temporary file for checks
&$error: (string) output: message key for message to show if upload canceled by
  returning false. May also be an array, where the first element is the message
  key and the remaining elements are used as parameters to the message.

'UploadVerifyFile': extra file verification, based on MIME type, etc. Preferred
in most cases over UploadVerification.
$upload: (object) an instance of UploadBase, with all info about the upload
$mime: (string) The uploaded file's MIME type, as detected by MediaWiki.
  Handlers will typically only apply for specific MIME types.
&$error: (object) output: true if the file is valid. Otherwise, an indexed array
  representing the problem with the file, where the first element is the message
  key and the remaining elements are used as parameters to the message.

'User::mailPasswordInternal': before creation and mailing of a user's new
temporary password
$user: the user who sent the message out
$ip: IP of the user who sent the message out
$u: the account whose new password will be set

'UserAddGroup': Called when adding a group; return false to override
stock group addition.
$user: the user object that is to have a group added
&$group: the group to add, can be modified

'UserArrayFromResult': Called when creating an UserArray object from a database
result.
&$userArray: set this to an object to override the default object returned
$res: database result used to create the object

'userCan': To interrupt/advise the "user can do X to Y article" check. If you
want to display an error message, try getUserPermissionsErrors.
$title: Title object being checked against
$user: Current user object
$action: Action being checked
$result: Pointer to result returned if hook returns false. If null is returned,
  userCan checks are continued by internal code.

'UserCanSendEmail': To override User::canSendEmail() permission check.
$user: User (object) whose permission is being checked
&$canSend: bool set on input, can override on output

'UserClearNewTalkNotification': Called when clearing the "You have new
messages!" message, return false to not delete it.
$user: User (object) that will clear the message
$oldid: ID of the talk page revision being viewed (0 means the most recent one)

'UserCreateForm': change to manipulate the login form
$template: SimpleTemplate instance for the form

'UserEffectiveGroups': Called in User::getEffectiveGroups().
$user: User to get groups for
&$groups: Current effective groups

'UserGetAllRights': After calculating a list of all available rights.
&$rights: Array of rights, which may be added to.

'UserGetDefaultOptions': After fetching the core default, this hook is run right
before returning the options to the caller. Warning: This hook is called for
every call to User::getDefaultOptions(), which means it's potentially called
dozens or hundreds of times. You may want to cache the results of non-trivial
operations in your hook function for this reason.
&$defaultOptions: Array of preference keys and their default values.

'UserGetEmail': Called when getting an user email address.
$user: User object
&$email: email, change this to override local email

'UserGetEmailAuthenticationTimestamp': Called when getting the timestamp of
email authentication.
$user: User object
&$timestamp: timestamp, change this to override local email authentication
  timestamp

'UserGetImplicitGroups': DEPRECATED!
Called in User::getImplicitGroups().
&$groups: List of implicit (automatically-assigned) groups

'UserGetLanguageObject': Called when getting user's interface language object.
$user: User object
&$code: Language code that will be used to create the object
$context: IContextSource object

'UserGetReservedNames': Allows to modify $wgReservedUsernames at run time.
&$reservedUsernames: $wgReservedUsernames

'UserGetRights': Called in User::getRights().
$user: User to get rights for
&$rights: Current rights

'UserGroupsChanged': Called after user groups are changed.
$user: User whose groups changed
$added: Groups added
$removed: Groups removed
$performer: User who performed the change, false if via autopromotion

'UserIsBlockedFrom': Check if a user is blocked from a specific page (for
specific block exemptions).
$user: User in question
$title: Title of the page in question
&$blocked: Out-param, whether or not the user is blocked from that page.
&$allowUsertalk: If the user is blocked, whether or not the block allows users
  to edit their own user talk pages.

'UserIsBlockedGlobally': Check if user is blocked on all wikis.
&$user: User object
$ip: User's IP address
&$blocked: Whether the user is blocked, to be modified by the hook

'UserIsEveryoneAllowed': Check if all users are allowed some user right; return
false if a UserGetRights hook might remove the named right.
$right: The user right being checked

'UserIsHidden': Check if the user's name should be hidden. See User::isHidden().
$user: User in question.
&$hidden: Set true if the user's name should be hidden.

'UserIsLocked': Check if the user is locked. See User::isLocked().
$user: User in question.
&$locked: Set true if the user should be locked.

'UserLoadAfterLoadFromSession': Called to authenticate users on external or
environmental means; occurs after session is loaded.
$user: user object being loaded

'UserLoadDefaults': Called when loading a default user.
$user: user object
$name: user name

'UserLoadFromDatabase': Called when loading a user from the database.
$user: user object
&$s: database query object

'UserLoadFromSession': Called to authenticate users on external/environmental
means; occurs before session is loaded.
$user: user object being loaded
&$result: set this to a boolean value to abort the normal authentication
  process

'UserLoadOptions': When user options/preferences are being loaded from the
database.
$user: User object
&$options: Options, can be modified.

'UserLoggedIn': Called after a user is logged in
$user: User object for the logged-in user

'UserLoginComplete': After a user has logged in.
$user: the user object that was created on login
$inject_html: Any HTML to inject after the "logged in" message.

'UserLoginForm': change to manipulate the login form
$template: SimpleTemplate instance for the form

'UserLogout': Before a user logs out.
$user: the user object that is about to be logged out

'UserLogoutComplete': After a user has logged out.
$user: the user object _after_ logout (won't have name, ID, etc.)
$inject_html: Any HTML to inject after the "logged out" message.
$oldName: name of the user before logout (string)

'UserMailerChangeReturnPath': Called to generate a VERP return address
when UserMailer sends an email, with a bounce handling extension.
$to: Array of MailAddress objects for the recipients
&$returnPath: The return address string

'UserRemoveGroup': Called when removing a group; return false to override stock
group removal.
$user: the user object that is to have a group removed
&$group: the group to be removed, can be modified

'UserRequiresHTTPS': Called to determine whether a user needs
to be switched to HTTPS.
$user: User in question.
&$https: Boolean whether $user should be switched to HTTPS.

'UserResetAllOptions': Called in User::resetOptions() when user preferences
have been requested to be reset. This hook can be used to exclude certain
options from being reset even when the user has requested all prefs to be reset,
because certain options might be stored in the user_properties database table
despite not being visible and editable via Special:Preferences.
$user: the User (object) whose preferences are being reset
&$newOptions: array of new (site default) preferences
$options: array of the user's old preferences
$resetKinds: array containing the kinds of preferences to reset

'UserRetrieveNewTalks': Called when retrieving "You have new messages!"
message(s).
$user: user retrieving new talks messages
$talks: array of new talks page(s)

'UserRights': DEPRECATED! Use UserGroupsChanged instead.
After a user's group memberships are changed.
&$user: User object that was changed
$add: Array of strings corresponding to groups added
$remove: Array of strings corresponding to groups removed

'UserSaveOptions': Called just before saving user preferences/options.
$user: User object
&$options: Options, modifiable

'UserSaveSettings': Called when saving user settings.
$user: User object

'UserSetCookies': Called when setting user cookies.
$user: User object
&$session: session array, will be added to $_SESSION
&$cookies: cookies array mapping cookie name to its value

'UserSetEmail': Called when changing user email address.
$user: User object
&$email: new email, change this to override new email address

'UserSetEmailAuthenticationTimestamp': Called when setting the timestamp of
email authentication.
$user: User object
&$timestamp: new timestamp, change this to override local email
authentication timestamp

'UserToolLinksEdit': Called when generating a list of user tool links, e.g.
"Foobar (Talk | Contribs | Block)".
$userId: User id of the current user
$userText: User name of the current user
&$items: Array of user tool links as HTML fragments

'ValidateExtendedMetadataCache': Called to validate the cached metadata in
FormatMetadata::getExtendedMeta (return false means cache will be
invalidated and GetExtendedMetadata hook called again).
$timestamp: The timestamp metadata was generated
$file: The file the metadata is for

'WantedPages::getQueryInfo': Called in WantedPagesPage::getQueryInfo(), can be
used to alter the SQL query which gets the list of wanted pages.
&$wantedPages: WantedPagesPage object
&$query: query array, see QueryPage::getQueryInfo() for format documentation

'WatchArticle': Before a watch is added to an article.
$user: user that will watch
$page: WikiPage object to be watched
&$status: Status object to be returned if the hook returns false

'WatchArticleComplete': After a watch is added to an article.
$user: user that watched
$page: WikiPage object watched

'WatchlistEditorBeforeFormRender': Before building the Special:EditWatchlist
form, used to manipulate the list of pages or preload data based on that list.
&$watchlistInfo: array of watchlisted pages in
  [namespaceId => ['title1' => 1, 'title2' => 1]] format

'WatchlistEditorBuildRemoveLine': when building remove lines in
Special:Watchlist/edit.
&$tools: array of extra links
$title: Title object
$redirect: whether the page is a redirect
$skin: Skin object
&$link: HTML link to title

'WebRequestPathInfoRouter': While building the PathRouter to parse the
REQUEST_URI.
$router: The PathRouter instance

'WebResponseSetCookie': when setting a cookie in WebResponse::setcookie().
Return false to prevent setting of the cookie.
&$name: Cookie name passed to WebResponse::setcookie()
&$value: Cookie value passed to WebResponse::setcookie()
&$expire: Cookie expiration, as for PHP's setcookie()
$options: Options passed to WebResponse::setcookie()

'wfShellWikiCmd': Called when generating a shell-escaped command line string to
run a MediaWiki cli script.
&$script: MediaWiki cli script path
&$parameters: Array of arguments and options to the script
&$options: Associative array of options, may contain the 'php' and 'wrapper'
  keys

'wgQueryPages': Called when initialising list of QueryPage subclasses, use this
to add new query pages to be updated with maintenance/updateSpecialPages.php.
$qp: The list of QueryPages

'WhatLinksHereProps': Allows annotations to be added to WhatLinksHere
$row: The DB row of the entry.
$title: The Title of the page where the link comes FROM
$target: The Title of the page where the link goes TO
&$props: Array of HTML strings to display after the title.

'WikiExporter::dumpStableQuery': Get the SELECT query for "stable" revisions
dumps. One, and only one hook should set this, and return false.
&$tables: Database tables to use in the SELECT query
&$opts: Options to use for the query
&$join: Join conditions

'WikiPageDeletionUpdates': manipulate the list of DataUpdates to be applied when
a page is deleted. Called in WikiPage::getDeletionUpdates(). Note that updates
specific to a content model should be provided by the respective Content's
getDeletionUpdates() method.
$page: the WikiPage
$content: the Content to generate updates for
&$updates: the array of DataUpdate objects. Hook function may want to add to it.

'XmlDumpWriterOpenPage': Called at the end of XmlDumpWriter::openPage, to allow
extra metadata to be added.
$obj: The XmlDumpWriter object.
&$out: The output string.
$row: The database row for the page.
$title: The title of the page.

'XmlDumpWriterWriteRevision': Called at the end of a revision in an XML dump, to
add extra metadata.
$obj: The XmlDumpWriter object.
&$out: The text being output.
$row: The database row for the revision.
$text: The revision text.

More hooks might be available but undocumented, you can execute
"php maintenance/findHooks.php" to find hidden ones.