--- /dev/null
+<?php
+use MediaWiki\MediaWikiServices;
+
+/**
+ * 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;
+
+ /**
+ * @var int Compilation flags passed to LightnCandy
+ */
+ // Do not add more flags here without discussion.
+ // If you do add more flags, be sure to update unit tests as well.
+ protected $compileFlags = LightnCandy::FLAG_ERROR_EXCEPTION;
+
+ /**
+ * @param string $templateDir
+ * @param bool $forceRecompile
+ */
+ public function __construct( $templateDir = null, $forceRecompile = false ) {
+ $this->templateDir = $templateDir ?: __DIR__ . '/templates';
+ $this->forceRecompile = $forceRecompile;
+ }
+
+ /**
+ * Enable/disable the use of recursive partials.
+ * @param bool $enable
+ */
+ public function enableRecursivePartials( $enable ) {
+ if ( $enable ) {
+ $this->compileFlags = $this->compileFlags | LightnCandy::FLAG_RUNTIMEPARTIAL;
+ } else {
+ $this->compileFlags = $this->compileFlags & ~LightnCandy::FLAG_RUNTIMEPARTIAL;
+ }
+ }
+
+ /**
+ * Constructs the location of the the source Mustache template
+ * @param string $templateName The name of the template
+ * @return string
+ * @throws UnexpectedValueException If $templateName attempts upwards directory traversal
+ */
+ protected function getTemplateFilename( $templateName ) {
+ // Prevent path traversal. Based on Language::isValidCode().
+ // This is for paranoia. The $templateName should never come from
+ // untrusted input.
+ if (
+ strcspn( $templateName, ":/\\\000&<>'\"%" ) !== strlen( $templateName )
+ ) {
+ 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 ) {
+ $templateKey = $templateName . '|' . $this->compileFlags;
+
+ // If a renderer has already been defined for this template, reuse it
+ if ( isset( $this->renderers[$templateKey] ) &&
+ is_callable( $this->renderers[$templateKey] )
+ ) {
+ return $this->renderers[$templateKey];
+ }
+
+ $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( $this->compileFlags . '|' . $fileContents );
+
+ // Fetch a secret key for building a keyed hash of the PHP code
+ $config = MediaWikiServices::getInstance()->getMainConfig();
+ $secretKey = $config->get( 'SecretKey' );
+
+ if ( $secretKey ) {
+ // See if the compiled PHP code is stored in cache.
+ $cache = ObjectCache::getLocalServerInstance( CACHE_ANYTHING );
+ $key = $cache->makeKey( 'template', $templateName, $fastHash );
+ $code = $this->forceRecompile ? null : $cache->get( $key );
+
+ if ( $code ) {
+ // Verify the integrity of the cached PHP code
+ $keyedHash = substr( $code, 0, 64 );
+ $code = substr( $code, 64 );
+ if ( $keyedHash !== hash_hmac( 'sha256', $code, $secretKey ) ) {
+ // If the integrity check fails, don't use the cached code
+ // We'll update the invalid cache below
+ $code = null;
+ }
+ }
+ if ( !$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 );
+ }
+ // 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" );
+ }
+ $this->renderers[$templateKey] = $renderer;
+ return $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,
+ [
+ 'flags' => $this->compileFlags,
+ 'basedir' => $this->templateDir,
+ 'fileext' => '.mustache',
+ ]
+ );
+ }
+
+ /**
+ * Returns HTML for a given template by calling the template function with the given args
+ *
+ * @code
+ * echo $templateParser->processTemplate(
+ * 'ExampleTemplate',
+ * [
+ * '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 = [] ) {
+ $template = $this->getTemplate( $templateName );
+ return call_user_func( $template, $args, $scopes );
+ }
+}
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