1 files changed, 201 insertions, 0 deletions
diff --git a/includes/TemplateParser.php b/includes/TemplateParser.php
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+++ b/includes/TemplateParser.php
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+<?php
+/**
+ * Handles compiling Mustache templates into PHP rendering functions
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @since 1.25
+ */
+class TemplateParser {
+	/**
+	 * @var string The path to the Mustache templates
+	 */
+	protected $templateDir;
+
+	/**
+	 * @var callable[] Array of cached rendering functions
+	 */
+	protected $renderers;
+
+	/**
+	 * @var bool Always compile template files
+	 */
+	protected $forceRecompile = false;
+
+	/**
+	 * @param string $templateDir
+	 * @param boolean $forceRecompile
+	 */
+	public function __construct( $templateDir = null, $forceRecompile = false ) {
+		$this->templateDir = $templateDir ? $templateDir : __DIR__ . '/templates';
+		$this->forceRecompile = $forceRecompile;
+	}
+
+	/**
+	 * Constructs the location of the the source Mustache template
+	 * @param string $templateName The name of the template
+	 * @return string
+	 * @throws UnexpectedValueException Disallows upwards directory traversal via $templateName
+	 */
+	protected function getTemplateFilename( $templateName ) {
+		// Prevent upwards directory traversal using same methods as Title::secureAndSplit
+		if (
+			strpos( $templateName, '.' ) !== false &&
+			(
+				$templateName === '.' || $templateName === '..' ||
+				strpos( $templateName, './' ) === 0 ||
+				strpos( $templateName, '../' ) === 0 ||
+				strpos( $templateName, '/./' ) !== false ||
+				strpos( $templateName, '/../' ) !== false ||
+				substr( $templateName, -2 ) === '/.' ||
+				substr( $templateName, -3 ) === '/..'
+			)
+		) {
+			throw new UnexpectedValueException( "Malformed \$templateName: $templateName" );
+		}
+
+		return "{$this->templateDir}/{$templateName}.mustache";
+	}
+
+	/**
+	 * Returns a given template function if found, otherwise throws an exception.
+	 * @param string $templateName The name of the template (without file suffix)
+	 * @return callable
+	 * @throws RuntimeException
+	 */
+	protected function getTemplate( $templateName ) {
+		// If a renderer has already been defined for this template, reuse it
+		if ( isset( $this->renderers[$templateName] ) && is_callable( $this->renderers[$templateName] ) ) {
+			return $this->renderers[$templateName];
+		}
+
+		$filename = $this->getTemplateFilename( $templateName );
+
+		if ( !file_exists( $filename ) ) {
+			throw new RuntimeException( "Could not locate template: {$filename}" );
+		}
+
+		// Read the template file
+		$fileContents = file_get_contents( $filename );
+
+		// Generate a quick hash for cache invalidation
+		$fastHash = md5( $fileContents );
+
+		// Fetch a secret key for building a keyed hash of the PHP code
+		$config = ConfigFactory::getDefaultInstance()->makeConfig( 'main' );
+		$secretKey = $config->get( 'SecretKey' );
+
+		if ( $secretKey ) {
+			// See if the compiled PHP code is stored in cache.
+			// CACHE_ACCEL throws an exception if no suitable object cache is present, so fall
+			// back to CACHE_ANYTHING.
+			$cache = ObjectCache::newAccelerator( array(), CACHE_ANYTHING );
+			$key = wfMemcKey( 'template', $templateName, $fastHash );
+			$code = $this->forceRecompile ? null : $cache->get( $key );
+
+			if ( !$code ) {
+				$code = $this->compileForEval( $fileContents, $filename );
+
+				// Prefix the cached code with a keyed hash (64 hex chars) as an integrity check
+				$cache->set( $key, hash_hmac( 'sha256', $code, $secretKey ) . $code );
+			} else {
+				// Verify the integrity of the cached PHP code
+				$keyedHash = substr( $code, 0, 64 );
+				$code = substr( $code, 64 );
+				if ( $keyedHash !== hash_hmac( 'sha256', $code, $secretKey ) ) {
+					// Generate a notice if integrity check fails
+					trigger_error( "Template failed integrity check: {$filename}" );
+				}
+			}
+		// If there is no secret key available, don't use cache
+		} else {
+			$code = $this->compileForEval( $fileContents, $filename );
+		}
+
+		$renderer = eval( $code );
+		if ( !is_callable( $renderer ) ) {
+			throw new RuntimeException( "Requested template, {$templateName}, is not callable" );
+		}
+		return $this->renderers[$templateName] = $renderer;
+	}
+
+	/**
+	 * Wrapper for compile() function that verifies successful compilation and strips
+	 * out the '<?php' part so that the code is ready for eval()
+	 * @param string $fileContents Mustache code
+	 * @param string $filename Name of the template
+	 * @return string PHP code (without '<?php')
+	 * @throws RuntimeException
+	 */
+	protected function compileForEval( $fileContents, $filename ) {
+		// Compile the template into PHP code
+		$code = $this->compile( $fileContents );
+
+		if ( !$code ) {
+			throw new RuntimeException( "Could not compile template: {$filename}" );
+		}
+
+		// Strip the "<?php" added by lightncandy so that it can be eval()ed
+		if ( substr( $code, 0, 5 ) === '<?php' ) {
+			$code = substr( $code, 5 );
+		}
+
+		return $code;
+	}
+
+	/**
+	 * Compile the Mustache code into PHP code using LightnCandy
+	 * @param string $code Mustache code
+	 * @return string PHP code (with '<?php')
+	 * @throws RuntimeException
+	 */
+	protected function compile( $code ) {
+		if ( !class_exists( 'LightnCandy' ) ) {
+			throw new RuntimeException( 'LightnCandy class not defined' );
+		}
+		return LightnCandy::compile(
+			$code,
+			array(
+				// Do not add more flags here without discussion.
+				// If you do add more flags, be sure to update unit tests as well.
+				'flags' => LightnCandy::FLAG_ERROR_EXCEPTION
+			)
+		);
+	}
+
+	/**
+	 * Returns HTML for a given template by calling the template function with the given args
+	 *
+	 * @code
+	 *     echo $templateParser->processTemplate(
+	 *         'ExampleTemplate',
+	 *         array(
+	 *             'username' => $user->getName(),
+	 *             'message' => 'Hello!'
+	 *         )
+	 *     );
+	 * @endcode
+	 * @param string $templateName The name of the template
+	 * @param mixed $args
+	 * @param array $scopes
+	 * @return string
+	 */
+	public function processTemplate( $templateName, $args, array $scopes = array() ) {
+		$template = $this->getTemplate( $templateName );
+		return call_user_func( $template, $args, $scopes );
+	}
+}