ResourceLoaderStartUpModule.php

Go to the documentation of this file.

<?php
class ResourceLoaderStartUpModule extends ResourceLoaderModule {
    protected $targets = [ 'desktop', 'mobile' ];
 
    private $groupIds = [
        // These reserved numbers MUST start at 0 and not skip any. These are preset
        // for forward compatibility so that they can be safely referenced by mediawiki.js,
        // even when the code is cached and the order of registrations (and implicit
        // group ids) changes between versions of the software.
        'user' => 0,
        'private' => 1,
    ];
 
    protected static function getImplicitDependencies(
        array $registryData,
        string $moduleName,
        array $handled = []
    ) : array {
        static $dependencyCache = [];
 
        // No modules will be added or changed server-side after this point,
        // so we can safely cache parts of the tree for re-use.
        if ( !isset( $dependencyCache[$moduleName] ) ) {
            if ( !isset( $registryData[$moduleName] ) ) {
                // Unknown module names are allowed here, this is only an optimisation.
                // Checks for illegal and unknown dependencies happen as PHPUnit structure tests,
                // and also client-side at run-time.
                $flat = [];
            } else {
                $data = $registryData[$moduleName];
                $flat = $data['dependencies'];
 
                // Prevent recursion
                $handled[] = $moduleName;
                foreach ( $data['dependencies'] as $dependency ) {
                    if ( in_array( $dependency, $handled, true ) ) {
                        // If we encounter a circular dependency, then stop the optimiser and leave the
                        // original dependencies array unmodified. Circular dependencies are not
                        // supported in ResourceLoader. Awareness of them exists here so that we can
                        // optimise the registry when it isn't broken, and otherwise transport the
                        // registry unchanged. The client will handle this further.
                        throw new ResourceLoaderCircularDependencyError();
                    } else {
                        // Recursively add the dependencies of the dependencies
                        $flat = array_merge(
                            $flat,
                            self::getImplicitDependencies( $registryData, $dependency, $handled )
                        );
                    }
                }
            }
 
            $dependencyCache[$moduleName] = $flat;
        }
 
        return $dependencyCache[$moduleName];
    }
 
    public static function compileUnresolvedDependencies( array &$registryData ) : void {
        foreach ( $registryData as $name => &$data ) {
            $dependencies = $data['dependencies'];
            try {
                foreach ( $data['dependencies'] as $dependency ) {
                    $implicitDependencies = self::getImplicitDependencies( $registryData, $dependency );
                    $dependencies = array_diff( $dependencies, $implicitDependencies );
                }
            } catch ( ResourceLoaderCircularDependencyError $err ) {
                // Leave unchanged
                $dependencies = $data['dependencies'];
            }
 
            // Rebuild keys
            $data['dependencies'] = array_values( $dependencies );
        }
    }
 
    public function getModuleRegistrations( ResourceLoaderContext $context ) : string {
        $resourceLoader = $context->getResourceLoader();
        // Future developers: Use WebRequest::getRawVal() instead getVal().
        // The getVal() method performs slow Language+UTF logic. (f303bb9360)
        $target = $context->getRequest()->getRawVal( 'target', 'desktop' );
        $safemode = $context->getRequest()->getRawVal( 'safemode' ) === '1';
        // Bypass target filter if this request is Special:JavaScriptTest.
        // To prevent misuse in production, this is only allowed if testing is enabled server-side.
        $byPassTargetFilter = $this->getConfig()->get( 'EnableJavaScriptTest' ) && $target === 'test';
 
        $out = '';
        $states = [];
        $registryData = [];
        $moduleNames = $resourceLoader->getModuleNames();
 
        // Preload with a batch so that the below calls to getVersionHash() for each module
        // don't require on-demand loading of more information.
        try {
            $resourceLoader->preloadModuleInfo( $moduleNames, $context );
        } catch ( Exception $e ) {
            // Don't fail the request (T152266)
            // Also print the error in the main output
            $resourceLoader->outputErrorAndLog( $e,
                'Preloading module info from startup failed: {exception}',
                [ 'exception' => $e ]
            );
        }
 
        // Get registry data
        foreach ( $moduleNames as $name ) {
            $module = $resourceLoader->getModule( $name );
            $moduleTargets = $module->getTargets();
            if (
                ( !$byPassTargetFilter && !in_array( $target, $moduleTargets ) )
                || ( $safemode && $module->getOrigin() > ResourceLoaderModule::ORIGIN_CORE_INDIVIDUAL )
            ) {
                continue;
            }
 
            if ( $module instanceof ResourceLoaderStartUpModule ) {
                // Don't register 'startup' to the client because loading it lazily or depending
                // on it doesn't make sense, because the startup module *is* the client.
                // Registering would be a waste of bandwidth and memory and risks somehow causing
                // it to load a second time.
 
                // ATTENTION: Because of the line below, this is not going to cause infinite recursion.
                // Think carefully before making changes to this code!
                // The below code is going to call ResourceLoaderModule::getVersionHash() for every module.
                // For StartUpModule (this module) the hash is computed based on the manifest content,
                // which is the very thing we are computing right here. As such, this must skip iterating
                // over 'startup' itself.
                continue;
            }
 
            try {
                $versionHash = $module->getVersionHash( $context );
            } catch ( Exception $e ) {
                // Don't fail the request (T152266)
                // Also print the error in the main output
                $resourceLoader->outputErrorAndLog( $e,
                    'Calculating version for "{module}" failed: {exception}',
                    [
                        'module' => $name,
                        'exception' => $e,
                    ]
                );
                $versionHash = '';
                $states[$name] = 'error';
            }
 
            if ( $versionHash !== '' && strlen( $versionHash ) !== ResourceLoader::HASH_LENGTH ) {
                $e = new RuntimeException( "Badly formatted module version hash" );
                $resourceLoader->outputErrorAndLog( $e,
                        "Module '{module}' produced an invalid version hash: '{version}'.",
                    [
                        'module' => $name,
                        'version' => $versionHash,
                    ]
                );
                // Module implementation either broken or deviated from ResourceLoader::makeHash
                // Asserted by tests/phpunit/structure/ResourcesTest.
                $versionHash = ResourceLoader::makeHash( $versionHash );
            }
 
            $skipFunction = $module->getSkipFunction();
            if ( $skipFunction !== null && !$context->getDebug() ) {
                $skipFunction = ResourceLoader::filter( 'minify-js', $skipFunction );
            }
 
            $registryData[$name] = [
                'version' => $versionHash,
                'dependencies' => $module->getDependencies( $context ),
                'group' => $this->getGroupId( $module->getGroup() ),
                'source' => $module->getSource(),
                'skip' => $skipFunction,
            ];
        }
 
        self::compileUnresolvedDependencies( $registryData );
 
        // Register sources
        $out .= ResourceLoader::makeLoaderSourcesScript( $context, $resourceLoader->getSources() );
 
        // Figure out the different call signatures for mw.loader.register
        $registrations = [];
        foreach ( $registryData as $name => $data ) {
            // Call mw.loader.register(name, version, dependencies, group, source, skip)
            $registrations[] = [
                $name,
                $data['version'],
                $data['dependencies'],
                $data['group'],
                // Swap default (local) for null
                $data['source'] === 'local' ? null : $data['source'],
                $data['skip']
            ];
        }
 
        // Register modules
        $out .= "\n" . ResourceLoader::makeLoaderRegisterScript( $context, $registrations );
 
        if ( $states ) {
            $out .= "\n" . ResourceLoader::makeLoaderStateScript( $context, $states );
        }
 
        return $out;
    }
 
    private function getGroupId( $groupName ) : ?int {
        if ( $groupName === null ) {
            return null;
        }
 
        if ( !array_key_exists( $groupName, $this->groupIds ) ) {
            $this->groupIds[$groupName] = count( $this->groupIds );
        }
 
        return $this->groupIds[$groupName];
    }
 
    private function getBaseModules() : array {
        return [ 'jquery', 'mediawiki.base' ];
    }
 
    private function getStoreKey() : string {
        return 'MediaWikiModuleStore:' . $this->getConfig()->get( 'DBname' );
    }
 
    private function getMaxQueryLength() : int {
        $len = $this->getConfig()->get( 'ResourceLoaderMaxQueryLength' );
        // - Ignore -1, which in MW 1.34 and earlier was used to mean "unlimited".
        // - Ignore invalid values, e.g. non-int or other negative values.
        if ( $len === false || $len < 0 ) {
            // Default
            $len = 2000;
        }
        return $len;
    }
 
    private function getStoreVary( ResourceLoaderContext $context ) : string {
        return implode( ':', [
            $context->getSkin(),
            $this->getConfig()->get( 'ResourceLoaderStorageVersion' ),
            $context->getLanguage(),
        ] );
    }
 
    public function getScript( ResourceLoaderContext $context ) : string {
        global $IP;
        $conf = $this->getConfig();
 
        if ( $context->getOnly() !== 'scripts' ) {
            return '/* Requires only=scripts */';
        }
 
        $startupCode = file_get_contents( "$IP/resources/src/startup/startup.js" );
 
        // The files read here MUST be kept in sync with maintenance/jsduck/eg-iframe.html,
        // and MUST be considered by 'fileHashes' in StartUpModule::getDefinitionSummary().
        $mwLoaderCode = file_get_contents( "$IP/resources/src/startup/mediawiki.js" ) .
            file_get_contents( "$IP/resources/src/startup/mediawiki.requestIdleCallback.js" );
        if ( $context->getDebug() ) {
            $mwLoaderCode .= file_get_contents( "$IP/resources/src/startup/mediawiki.log.js" );
        }
        if ( $conf->get( 'ResourceLoaderEnableJSProfiler' ) ) {
            $mwLoaderCode .= file_get_contents( "$IP/resources/src/startup/profiler.js" );
        }
 
        // Perform replacements for mediawiki.js
        $mwLoaderPairs = [
            // This should always be an object, even if the base vars are empty
            // (such as when using the default lang/skin).
            '$VARS.reqBase' => $context->encodeJson( (object)$context->getReqBase() ),
            '$VARS.baseModules' => $context->encodeJson( $this->getBaseModules() ),
            '$VARS.maxQueryLength' => $context->encodeJson( $this->getMaxQueryLength() ),
            // The client-side module cache can be disabled by site configuration.
            // It is also always disabled in debug mode.
            '$VARS.storeEnabled' => $context->encodeJson(
                $conf->get( 'ResourceLoaderStorageEnabled' ) && !$context->getDebug()
            ),
            '$VARS.wgLegacyJavaScriptGlobals' => $context->encodeJson(
                $conf->get( 'LegacyJavaScriptGlobals' )
            ),
            '$VARS.storeKey' => $context->encodeJson( $this->getStoreKey() ),
            '$VARS.storeVary' => $context->encodeJson( $this->getStoreVary( $context ) ),
            '$VARS.groupUser' => $context->encodeJson( $this->getGroupId( 'user' ) ),
            '$VARS.groupPrivate' => $context->encodeJson( $this->getGroupId( 'private' ) ),
        ];
        $profilerStubs = [
            '$CODE.profileExecuteStart();' => 'mw.loader.profiler.onExecuteStart( module );',
            '$CODE.profileExecuteEnd();' => 'mw.loader.profiler.onExecuteEnd( module );',
            '$CODE.profileScriptStart();' => 'mw.loader.profiler.onScriptStart( module );',
            '$CODE.profileScriptEnd();' => 'mw.loader.profiler.onScriptEnd( module );',
        ];
        if ( $conf->get( 'ResourceLoaderEnableJSProfiler' ) ) {
            // When profiling is enabled, insert the calls.
            $mwLoaderPairs += $profilerStubs;
        } else {
            // When disabled (by default), insert nothing.
            $mwLoaderPairs += array_fill_keys( array_keys( $profilerStubs ), '' );
        }
        $mwLoaderCode = strtr( $mwLoaderCode, $mwLoaderPairs );
 
        // Perform string replacements for startup.js
        $pairs = [
            // Raw JavaScript code (not JSON)
            '$CODE.registrations();' => trim( $this->getModuleRegistrations( $context ) ),
            '$CODE.defineLoader();' => $mwLoaderCode,
        ];
        $startupCode = strtr( $startupCode, $pairs );
 
        return $startupCode;
    }
 
    public function supportsURLLoading() : bool {
        return false;
    }
 
    public function enableModuleContentVersion() : bool {
        // Enabling this means that ResourceLoader::getVersionHash will simply call getScript()
        // and hash it to determine the version (as used by E-Tag HTTP response header).
        return true;
    }
}