ApiHelp.php

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<?php
use HtmlFormatter\HtmlFormatter;
use MediaWiki\MediaWikiServices;

class ApiHelp extends ApiBase {
    public function execute() {
        $params = $this->extractRequestParams();
        $modules = [];

        foreach ( $params['modules'] as $path ) {
            $modules[] = $this->getModuleFromPath( $path );
        }

        // Get the help
        $context = new DerivativeContext( $this->getMain()->getContext() );
        $context->setSkin( SkinFactory::getDefaultInstance()->makeSkin( 'apioutput' ) );
        $context->setLanguage( $this->getMain()->getLanguage() );
        $context->setTitle( SpecialPage::getTitleFor( 'ApiHelp' ) );
        $out = new OutputPage( $context );
        $out->setCopyrightUrl( 'https://www.mediawiki.org/wiki/Special:MyLanguage/Copyright' );
        $context->setOutput( $out );

        self::getHelp( $context, $modules, $params );

        // Grab the output from the skin
        ob_start();
        $context->getOutput()->output();
        $html = ob_get_clean();

        $result = $this->getResult();
        if ( $params['wrap'] ) {
            $data = [
                'mime' => 'text/html',
                'filename' => 'api-help.html',
                'help' => $html,
            ];
            ApiResult::setSubelementsList( $data, 'help' );
            $result->addValue( null, $this->getModuleName(), $data );
        } else {
            $result->reset();
            $result->addValue( null, 'text', $html, ApiResult::NO_SIZE_CHECK );
            $result->addValue( null, 'mime', 'text/html', ApiResult::NO_SIZE_CHECK );
            $result->addValue( null, 'filename', 'api-help.html', ApiResult::NO_SIZE_CHECK );
        }
    }

    public static function getHelp( IContextSource $context, $modules, array $options ) {
        if ( !is_array( $modules ) ) {
            $modules = [ $modules ];
        }

        $out = $context->getOutput();
        $out->addModuleStyles( [
            'mediawiki.hlist',
            'mediawiki.apihelp',
        ] );
        if ( !empty( $options['toc'] ) ) {
            $out->addModules( 'mediawiki.toc' );
            $out->addModuleStyles( 'mediawiki.toc.styles' );
        }
        $out->setPageTitle( $context->msg( 'api-help-title' ) );

        $services = MediaWikiServices::getInstance();
        $cache = $services->getMainWANObjectCache();
        $cacheKey = null;
        if ( count( $modules ) == 1 && $modules[0] instanceof ApiMain &&
            $options['recursivesubmodules'] &&
            $context->getLanguage()->equals( $services->getContentLanguage() )
        ) {
            $cacheHelpTimeout = $context->getConfig()->get( 'APICacheHelpTimeout' );
            if ( $cacheHelpTimeout > 0 ) {
                // Get help text from cache if present
                $cacheKey = $cache->makeKey( 'apihelp', $modules[0]->getModulePath(),
                    (int)!empty( $options['toc'] ),
                    str_replace( ' ', '_', SpecialVersion::getVersion( 'nodb' ) ) );
                $cached = $cache->get( $cacheKey );
                if ( $cached ) {
                    $out->addHTML( $cached );
                    return;
                }
            }
        }
        if ( $out->getHTML() !== '' ) {
            // Don't save to cache, there's someone else's content in the page
            // already
            $cacheKey = null;
        }

        $options['recursivesubmodules'] = !empty( $options['recursivesubmodules'] );
        $options['submodules'] = $options['recursivesubmodules'] || !empty( $options['submodules'] );

        // Prepend lead
        if ( empty( $options['nolead'] ) ) {
            $msg = $context->msg( 'api-help-lead' );
            if ( !$msg->isDisabled() ) {
                $out->addHTML( $msg->parseAsBlock() );
            }
        }

        $haveModules = [];
        $html = self::getHelpInternal( $context, $modules, $options, $haveModules );
        if ( !empty( $options['toc'] ) && $haveModules ) {
            $out->addHTML( Linker::generateTOC( $haveModules, $context->getLanguage() ) );
        }
        $out->addHTML( $html );

        $helptitle = $options['helptitle'] ?? null;
        $html = self::fixHelpLinks( $out->getHTML(), $helptitle, $haveModules );
        $out->clearHTML();
        $out->addHTML( $html );

        if ( $cacheKey !== null ) {
            $cache->set( $cacheKey, $out->getHTML(), $cacheHelpTimeout );
        }
    }

    public static function fixHelpLinks( $html, $helptitle = null, $localModules = [] ) {
        $formatter = new HtmlFormatter( $html );
        $doc = $formatter->getDoc();
        $xpath = new DOMXPath( $doc );
        $nodes = $xpath->query( '//a[@href][not(contains(@class,\'apihelp-linktrail\'))]' );
        foreach ( $nodes as $node ) {
            $href = $node->getAttribute( 'href' );
            do {
                $old = $href;
                $href = rawurldecode( $href );
            } while ( $old !== $href );
            if ( preg_match( '!Special:ApiHelp/([^&/|#]+)((?:#.*)?)!', $href, $m ) ) {
                if ( isset( $localModules[$m[1]] ) ) {
                    $href = $m[2] === '' ? '#' . $m[1] : $m[2];
                } elseif ( $helptitle !== null ) {
                    $href = Title::newFromText( str_replace( '$1', $m[1], $helptitle ) . $m[2] )
                        ->getFullURL();
                } else {
                    $href = wfAppendQuery( wfScript( 'api' ), [
                        'action' => 'help',
                        'modules' => $m[1],
                    ] ) . $m[2];
                }
                $node->setAttribute( 'href', $href );
                $node->removeAttribute( 'title' );
            }
        }

        return $formatter->getText();
    }

    private static function wrap( Message $msg, $class, $tag = 'span' ) {
        return Html::rawElement( $tag, [ 'class' => $class ],
            $msg->parse()
        );
    }

    private static function getHelpInternal( IContextSource $context, array $modules,
        array $options, &$haveModules
    ) {
        $out = '';

        $level = empty( $options['headerlevel'] ) ? 2 : $options['headerlevel'];
        if ( empty( $options['tocnumber'] ) ) {
            $tocnumber = [ 2 => 0 ];
        } else {
            $tocnumber = &$options['tocnumber'];
        }

        foreach ( $modules as $module ) {
            $tocnumber[$level]++;
            $path = $module->getModulePath();
            $module->setContext( $context );
            $help = [
                'header' => '',
                'flags' => '',
                'description' => '',
                'help-urls' => '',
                'parameters' => '',
                'examples' => '',
                'submodules' => '',
            ];

            if ( empty( $options['noheader'] ) || !empty( $options['toc'] ) ) {
                $anchor = $path;
                $i = 1;
                while ( isset( $haveModules[$anchor] ) ) {
                    $anchor = $path . '|' . ++$i;
                }

                if ( $module->isMain() ) {
                    $headerContent = $context->msg( 'api-help-main-header' )->parse();
                    $headerAttr = [
                        'class' => 'apihelp-header',
                    ];
                } else {
                    $name = $module->getModuleName();
                    $headerContent = $module->getParent()->getModuleManager()->getModuleGroup( $name ) .
                        "=$name";
                    if ( $module->getModulePrefix() !== '' ) {
                        $headerContent .= ' ' .
                            $context->msg( 'parentheses', $module->getModulePrefix() )->parse();
                    }
                    // Module names are always in English and not localized,
                    // so English language and direction must be set explicitly,
                    // otherwise parentheses will get broken in RTL wikis
                    $headerAttr = [
                        'class' => 'apihelp-header apihelp-module-name',
                        'dir' => 'ltr',
                        'lang' => 'en',
                    ];
                }

                $headerAttr['id'] = $anchor;

                $haveModules[$anchor] = [
                    'toclevel' => count( $tocnumber ),
                    'level' => $level,
                    'anchor' => $anchor,
                    'line' => $headerContent,
                    'number' => implode( '.', $tocnumber ),
                    'index' => false,
                ];
                if ( empty( $options['noheader'] ) ) {
                    $help['header'] .= Html::element(
                        'h' . min( 6, $level ),
                        $headerAttr,
                        $headerContent
                    );
                }
            } else {
                $haveModules[$path] = true;
            }

            $links = [];
            $any = false;
            for ( $m = $module; $m !== null; $m = $m->getParent() ) {
                $name = $m->getModuleName();
                if ( $name === 'main_int' ) {
                    $name = 'main';
                }

                if ( count( $modules ) === 1 && $m === $modules[0] &&
                    !( !empty( $options['submodules'] ) && $m->getModuleManager() )
                ) {
                    $link = Html::element( 'b', [ 'dir' => 'ltr', 'lang' => 'en' ], $name );
                } else {
                    $link = SpecialPage::getTitleFor( 'ApiHelp', $m->getModulePath() )->getLocalURL();
                    $link = Html::element( 'a',
                        [ 'href' => $link, 'class' => 'apihelp-linktrail', 'dir' => 'ltr', 'lang' => 'en' ],
                        $name
                    );
                    $any = true;
                }
                array_unshift( $links, $link );
            }
            if ( $any ) {
                $help['header'] .= self::wrap(
                    $context->msg( 'parentheses' )
                        ->rawParams( $context->getLanguage()->pipeList( $links ) ),
                    'apihelp-linktrail', 'div'
                );
            }

            $flags = $module->getHelpFlags();
            $help['flags'] .= Html::openElement( 'div',
                [ 'class' => 'apihelp-block apihelp-flags' ] );
            $msg = $context->msg( 'api-help-flags' );
            if ( !$msg->isDisabled() ) {
                $help['flags'] .= self::wrap(
                    $msg->numParams( count( $flags ) ), 'apihelp-block-head', 'div'
                );
            }
            $help['flags'] .= Html::openElement( 'ul' );
            foreach ( $flags as $flag ) {
                $help['flags'] .= Html::rawElement( 'li', null,
                    self::wrap( $context->msg( "api-help-flag-$flag" ), "apihelp-flag-$flag" )
                );
            }
            $sourceInfo = $module->getModuleSourceInfo();
            if ( $sourceInfo ) {
                if ( isset( $sourceInfo['namemsg'] ) ) {
                    $extname = $context->msg( $sourceInfo['namemsg'] )->text();
                } else {
                    // Probably English, so wrap it.
                    $extname = Html::element( 'span', [ 'dir' => 'ltr', 'lang' => 'en' ], $sourceInfo['name'] );
                }
                $help['flags'] .= Html::rawElement( 'li', null,
                    self::wrap(
                        $context->msg( 'api-help-source', $extname, $sourceInfo['name'] ),
                        'apihelp-source'
                    )
                );

                $link = SpecialPage::getTitleFor( 'Version', 'License/' . $sourceInfo['name'] );
                if ( isset( $sourceInfo['license-name'] ) ) {
                    $msg = $context->msg( 'api-help-license', $link,
                        Html::element( 'span', [ 'dir' => 'ltr', 'lang' => 'en' ], $sourceInfo['license-name'] )
                    );
                } elseif ( SpecialVersion::getExtLicenseFileName( dirname( $sourceInfo['path'] ) ) ) {
                    $msg = $context->msg( 'api-help-license-noname', $link );
                } else {
                    $msg = $context->msg( 'api-help-license-unknown' );
                }
                $help['flags'] .= Html::rawElement( 'li', null,
                    self::wrap( $msg, 'apihelp-license' )
                );
            } else {
                $help['flags'] .= Html::rawElement( 'li', null,
                    self::wrap( $context->msg( 'api-help-source-unknown' ), 'apihelp-source' )
                );
                $help['flags'] .= Html::rawElement( 'li', null,
                    self::wrap( $context->msg( 'api-help-license-unknown' ), 'apihelp-license' )
                );
            }
            $help['flags'] .= Html::closeElement( 'ul' );
            $help['flags'] .= Html::closeElement( 'div' );

            foreach ( $module->getFinalDescription() as $msg ) {
                $msg->setContext( $context );
                $help['description'] .= $msg->parseAsBlock();
            }

            $urls = $module->getHelpUrls();
            if ( $urls ) {
                $help['help-urls'] .= Html::openElement( 'div',
                    [ 'class' => 'apihelp-block apihelp-help-urls' ]
                );
                $msg = $context->msg( 'api-help-help-urls' );
                if ( !$msg->isDisabled() ) {
                    $help['help-urls'] .= self::wrap(
                        $msg->numParams( count( $urls ) ), 'apihelp-block-head', 'div'
                    );
                }
                if ( !is_array( $urls ) ) {
                    $urls = [ $urls ];
                }
                $help['help-urls'] .= Html::openElement( 'ul' );
                foreach ( $urls as $url ) {
                    $help['help-urls'] .= Html::rawElement( 'li', null,
                        Html::element( 'a', [ 'href' => $url, 'dir' => 'ltr' ], $url )
                    );
                }
                $help['help-urls'] .= Html::closeElement( 'ul' );
                $help['help-urls'] .= Html::closeElement( 'div' );
            }

            $params = $module->getFinalParams( ApiBase::GET_VALUES_FOR_HELP );
            $dynamicParams = $module->dynamicParameterDocumentation();
            $groups = [];
            if ( $params || $dynamicParams !== null ) {
                $help['parameters'] .= Html::openElement( 'div',
                    [ 'class' => 'apihelp-block apihelp-parameters' ]
                );
                $msg = $context->msg( 'api-help-parameters' );
                if ( !$msg->isDisabled() ) {
                    $help['parameters'] .= self::wrap(
                        $msg->numParams( count( $params ) ), 'apihelp-block-head', 'div'
                    );
                }
                $help['parameters'] .= Html::openElement( 'dl' );

                $descriptions = $module->getFinalParamDescription();

                foreach ( $params as $name => $settings ) {
                    if ( !is_array( $settings ) ) {
                        $settings = [ ApiBase::PARAM_DFLT => $settings ];
                    }

                    $help['parameters'] .= Html::rawElement( 'dt', null,
                        Html::element( 'span', [ 'dir' => 'ltr', 'lang' => 'en' ], $module->encodeParamName( $name ) )
                    );

                    // Add description
                    $description = [];
                    if ( isset( $descriptions[$name] ) ) {
                        foreach ( $descriptions[$name] as $msg ) {
                            $msg->setContext( $context );
                            $description[] = $msg->parseAsBlock();
                        }
                    }

                    // Add usage info
                    $info = [];

                    // Required?
                    if ( !empty( $settings[ApiBase::PARAM_REQUIRED] ) ) {
                        $info[] = $context->msg( 'api-help-param-required' )->parse();
                    }

                    // Custom info?
                    if ( !empty( $settings[ApiBase::PARAM_HELP_MSG_INFO] ) ) {
                        foreach ( $settings[ApiBase::PARAM_HELP_MSG_INFO] as $i ) {
                            $tag = array_shift( $i );
                            $info[] = $context->msg( "apihelp-{$path}-paraminfo-{$tag}" )
                                ->numParams( count( $i ) )
                                ->params( $context->getLanguage()->commaList( $i ) )
                                ->params( $module->getModulePrefix() )
                                ->parse();
                        }
                    }

                    // Templated?
                    if ( !empty( $settings[ApiBase::PARAM_TEMPLATE_VARS] ) ) {
                        $vars = [];
                        $msg = 'api-help-param-templated-var-first';
                        foreach ( $settings[ApiBase::PARAM_TEMPLATE_VARS] as $k => $v ) {
                            $vars[] = $context->msg( $msg, $k, $module->encodeParamName( $v ) );
                            $msg = 'api-help-param-templated-var';
                        }
                        $info[] = $context->msg( 'api-help-param-templated' )
                            ->numParams( count( $vars ) )
                            ->params( Message::listParam( $vars ) )
                            ->parse();
                    }

                    // Type documentation
                    if ( !isset( $settings[ApiBase::PARAM_TYPE] ) ) {
                        $dflt = $settings[ApiBase::PARAM_DFLT] ?? null;
                        if ( is_bool( $dflt ) ) {
                            $settings[ApiBase::PARAM_TYPE] = 'boolean';
                        } elseif ( is_string( $dflt ) || is_null( $dflt ) ) {
                            $settings[ApiBase::PARAM_TYPE] = 'string';
                        } elseif ( is_int( $dflt ) ) {
                            $settings[ApiBase::PARAM_TYPE] = 'integer';
                        }
                    }
                    if ( isset( $settings[ApiBase::PARAM_TYPE] ) ) {
                        $type = $settings[ApiBase::PARAM_TYPE];
                        $multi = !empty( $settings[ApiBase::PARAM_ISMULTI] );
                        $hintPipeSeparated = true;
                        $count = !empty( $settings[ApiBase::PARAM_ISMULTI_LIMIT2] )
                            ? $settings[ApiBase::PARAM_ISMULTI_LIMIT2] + 1
                            : ApiBase::LIMIT_SML2 + 1;

                        if ( is_array( $type ) ) {
                            $count = count( $type );
                            $deprecatedValues = $settings[ApiBase::PARAM_DEPRECATED_VALUES] ?? [];
                            $links = $settings[ApiBase::PARAM_VALUE_LINKS] ?? [];
                            $values = array_map( function ( $v ) use ( $links, $deprecatedValues ) {
                                $attr = [];
                                if ( $v !== '' ) {
                                    // We can't know whether this contains LTR or RTL text.
                                    $attr['dir'] = 'auto';
                                }
                                if ( isset( $deprecatedValues[$v] ) ) {
                                    $attr['class'] = 'apihelp-deprecated-value';
                                }
                                $ret = $attr ? Html::element( 'span', $attr, $v ) : $v;
                                if ( isset( $links[$v] ) ) {
                                    $ret = "[[{$links[$v]}|$ret]]";
                                }
                                return $ret;
                            }, $type );
                            $i = array_search( '', $type, true );
                            if ( $i === false ) {
                                $values = $context->getLanguage()->commaList( $values );
                            } else {
                                unset( $values[$i] );
                                $values = $context->msg( 'api-help-param-list-can-be-empty' )
                                    ->numParams( count( $values ) )
                                    ->params( $context->getLanguage()->commaList( $values ) )
                                    ->parse();
                            }
                            $info[] = $context->msg( 'api-help-param-list' )
                                ->params( $multi ? 2 : 1 )
                                ->params( $values )
                                ->parse();
                            $hintPipeSeparated = false;
                        } else {
                            switch ( $type ) {
                                case 'submodule':
                                    $groups[] = $name;

                                    if ( isset( $settings[ApiBase::PARAM_SUBMODULE_MAP] ) ) {
                                        $map = $settings[ApiBase::PARAM_SUBMODULE_MAP];
                                        $defaultAttrs = [];
                                    } else {
                                        $prefix = $module->isMain() ? '' : ( $module->getModulePath() . '+' );
                                        $map = [];
                                        foreach ( $module->getModuleManager()->getNames( $name ) as $submoduleName ) {
                                            $map[$submoduleName] = $prefix . $submoduleName;
                                        }
                                        $defaultAttrs = [ 'dir' => 'ltr', 'lang' => 'en' ];
                                    }
                                    ksort( $map );

                                    $submodules = [];
                                    $deprecatedSubmodules = [];
                                    foreach ( $map as $v => $m ) {
                                        $attrs = $defaultAttrs;
                                        $arr = &$submodules;
                                        try {
                                            $submod = $module->getModuleFromPath( $m );
                                            if ( $submod ) {
                                                if ( $submod->isDeprecated() ) {
                                                    $arr = &$deprecatedSubmodules;
                                                    $attrs['class'] = 'apihelp-deprecated-value';
                                                }
                                            }
                                        } catch ( ApiUsageException $ex ) {
                                            // Ignore
                                        }
                                        if ( $attrs ) {
                                            $v = Html::element( 'span', $attrs, $v );
                                        }
                                        $arr[] = "[[Special:ApiHelp/{$m}|{$v}]]";
                                    }
                                    $submodules = array_merge( $submodules, $deprecatedSubmodules );
                                    $count = count( $submodules );
                                    $info[] = $context->msg( 'api-help-param-list' )
                                        ->params( $multi ? 2 : 1 )
                                        ->params( $context->getLanguage()->commaList( $submodules ) )
                                        ->parse();
                                    $hintPipeSeparated = false;
                                    // No type message necessary, we have a list of values.
                                    $type = null;
                                    break;

                                case 'namespace':
                                    $namespaces = MWNamespace::getValidNamespaces();
                                    if ( isset( $settings[ApiBase::PARAM_EXTRA_NAMESPACES] ) &&
                                        is_array( $settings[ApiBase::PARAM_EXTRA_NAMESPACES] )
                                    ) {
                                        $namespaces = array_merge( $namespaces, $settings[ApiBase::PARAM_EXTRA_NAMESPACES] );
                                    }
                                    sort( $namespaces );
                                    $count = count( $namespaces );
                                    $info[] = $context->msg( 'api-help-param-list' )
                                        ->params( $multi ? 2 : 1 )
                                        ->params( $context->getLanguage()->commaList( $namespaces ) )
                                        ->parse();
                                    $hintPipeSeparated = false;
                                    // No type message necessary, we have a list of values.
                                    $type = null;
                                    break;

                                case 'tags':
                                    $tags = ChangeTags::listExplicitlyDefinedTags();
                                    $count = count( $tags );
                                    $info[] = $context->msg( 'api-help-param-list' )
                                        ->params( $multi ? 2 : 1 )
                                        ->params( $context->getLanguage()->commaList( $tags ) )
                                        ->parse();
                                    $hintPipeSeparated = false;
                                    $type = null;
                                    break;

                                case 'limit':
                                    if ( isset( $settings[ApiBase::PARAM_MAX2] ) ) {
                                        $info[] = $context->msg( 'api-help-param-limit2' )
                                            ->numParams( $settings[ApiBase::PARAM_MAX] )
                                            ->numParams( $settings[ApiBase::PARAM_MAX2] )
                                            ->parse();
                                    } else {
                                        $info[] = $context->msg( 'api-help-param-limit' )
                                            ->numParams( $settings[ApiBase::PARAM_MAX] )
                                            ->parse();
                                    }
                                    break;

                                case 'integer':
                                    // Possible messages:
                                    // api-help-param-integer-min,
                                    // api-help-param-integer-max,
                                    // api-help-param-integer-minmax
                                    $suffix = '';
                                    $min = $max = 0;
                                    if ( isset( $settings[ApiBase::PARAM_MIN] ) ) {
                                        $suffix .= 'min';
                                        $min = $settings[ApiBase::PARAM_MIN];
                                    }
                                    if ( isset( $settings[ApiBase::PARAM_MAX] ) ) {
                                        $suffix .= 'max';
                                        $max = $settings[ApiBase::PARAM_MAX];
                                    }
                                    if ( $suffix !== '' ) {
                                        $info[] =
                                            $context->msg( "api-help-param-integer-$suffix" )
                                                ->params( $multi ? 2 : 1 )
                                                ->numParams( $min, $max )
                                                ->parse();
                                    }
                                    break;

                                case 'upload':
                                    $info[] = $context->msg( 'api-help-param-upload' )
                                        ->parse();
                                    // No type message necessary, api-help-param-upload should handle it.
                                    $type = null;
                                    break;

                                case 'string':
                                case 'text':
                                    // Displaying a type message here would be useless.
                                    $type = null;
                                    break;
                            }
                        }

                        // Add type. Messages for grep: api-help-param-type-limit
                        // api-help-param-type-integer api-help-param-type-boolean
                        // api-help-param-type-timestamp api-help-param-type-user
                        // api-help-param-type-password
                        if ( is_string( $type ) ) {
                            $msg = $context->msg( "api-help-param-type-$type" );
                            if ( !$msg->isDisabled() ) {
                                $info[] = $msg->params( $multi ? 2 : 1 )->parse();
                            }
                        }

                        if ( $multi ) {
                            $extra = [];
                            $lowcount = !empty( $settings[ApiBase::PARAM_ISMULTI_LIMIT1] )
                                ? $settings[ApiBase::PARAM_ISMULTI_LIMIT1]
                                : ApiBase::LIMIT_SML1;
                            $highcount = !empty( $settings[ApiBase::PARAM_ISMULTI_LIMIT2] )
                                ? $settings[ApiBase::PARAM_ISMULTI_LIMIT2]
                                : ApiBase::LIMIT_SML2;

                            if ( $hintPipeSeparated ) {
                                $extra[] = $context->msg( 'api-help-param-multi-separate' )->parse();
                            }
                            if ( $count > $lowcount ) {
                                if ( $lowcount === $highcount ) {
                                    $msg = $context->msg( 'api-help-param-multi-max-simple' )
                                        ->numParams( $lowcount );
                                } else {
                                    $msg = $context->msg( 'api-help-param-multi-max' )
                                        ->numParams( $lowcount, $highcount );
                                }
                                $extra[] = $msg->parse();
                            }
                            if ( $extra ) {
                                $info[] = implode( ' ', $extra );
                            }

                            $allowAll = $settings[ApiBase::PARAM_ALL] ?? false;
                            if ( $allowAll || $settings[ApiBase::PARAM_TYPE] === 'namespace' ) {
                                if ( $settings[ApiBase::PARAM_TYPE] === 'namespace' ) {
                                    $allSpecifier = ApiBase::ALL_DEFAULT_STRING;
                                } else {
                                    $allSpecifier = ( is_string( $allowAll ) ? $allowAll : ApiBase::ALL_DEFAULT_STRING );
                                }
                                $info[] = $context->msg( 'api-help-param-multi-all' )
                                    ->params( $allSpecifier )
                                    ->parse();
                            }
                        }
                    }

                    if ( isset( $settings[self::PARAM_MAX_BYTES] ) ) {
                        $info[] = $context->msg( 'api-help-param-maxbytes' )
                            ->numParams( $settings[self::PARAM_MAX_BYTES] );
                    }
                    if ( isset( $settings[self::PARAM_MAX_CHARS] ) ) {
                        $info[] = $context->msg( 'api-help-param-maxchars' )
                            ->numParams( $settings[self::PARAM_MAX_CHARS] );
                    }

                    // Add default
                    $default = $settings[ApiBase::PARAM_DFLT] ?? null;
                    if ( $default === '' ) {
                        $info[] = $context->msg( 'api-help-param-default-empty' )
                            ->parse();
                    } elseif ( $default !== null && $default !== false ) {
                        // We can't know whether this contains LTR or RTL text.
                        $info[] = $context->msg( 'api-help-param-default' )
                            ->params( Html::element( 'span', [ 'dir' => 'auto' ], $default ) )
                            ->parse();
                    }

                    if ( !array_filter( $description ) ) {
                        $description = [ self::wrap(
                            $context->msg( 'api-help-param-no-description' ),
                            'apihelp-empty'
                        ) ];
                    }

                    // Add "deprecated" flag
                    if ( !empty( $settings[ApiBase::PARAM_DEPRECATED] ) ) {
                        $help['parameters'] .= Html::openElement( 'dd',
                            [ 'class' => 'info' ] );
                        $help['parameters'] .= self::wrap(
                            $context->msg( 'api-help-param-deprecated' ),
                            'apihelp-deprecated', 'strong'
                        );
                        $help['parameters'] .= Html::closeElement( 'dd' );
                    }

                    if ( $description ) {
                        $description = implode( '', $description );
                        $description = preg_replace( '!\s*</([oud]l)>\s*<\1>\s*!', "\n", $description );
                        $help['parameters'] .= Html::rawElement( 'dd',
                            [ 'class' => 'description' ], $description );
                    }

                    foreach ( $info as $i ) {
                        $help['parameters'] .= Html::rawElement( 'dd', [ 'class' => 'info' ], $i );
                    }
                }

                if ( $dynamicParams !== null ) {
                    $dynamicParams = ApiBase::makeMessage( $dynamicParams, $context, [
                        $module->getModulePrefix(),
                        $module->getModuleName(),
                        $module->getModulePath()
                    ] );
                    $help['parameters'] .= Html::element( 'dt', null, '*' );
                    $help['parameters'] .= Html::rawElement( 'dd',
                        [ 'class' => 'description' ], $dynamicParams->parse() );
                }

                $help['parameters'] .= Html::closeElement( 'dl' );
                $help['parameters'] .= Html::closeElement( 'div' );
            }

            $examples = $module->getExamplesMessages();
            if ( $examples ) {
                $help['examples'] .= Html::openElement( 'div',
                    [ 'class' => 'apihelp-block apihelp-examples' ] );
                $msg = $context->msg( 'api-help-examples' );
                if ( !$msg->isDisabled() ) {
                    $help['examples'] .= self::wrap(
                        $msg->numParams( count( $examples ) ), 'apihelp-block-head', 'div'
                    );
                }

                $help['examples'] .= Html::openElement( 'dl' );
                foreach ( $examples as $qs => $msg ) {
                    $msg = ApiBase::makeMessage( $msg, $context, [
                        $module->getModulePrefix(),
                        $module->getModuleName(),
                        $module->getModulePath()
                    ] );

                    $link = wfAppendQuery( wfScript( 'api' ), $qs );
                    $sandbox = SpecialPage::getTitleFor( 'ApiSandbox' )->getLocalURL() . '#' . $qs;
                    $help['examples'] .= Html::rawElement( 'dt', null, $msg->parse() );
                    $help['examples'] .= Html::rawElement( 'dd', null,
                        Html::element( 'a', [ 'href' => $link, 'dir' => 'ltr' ], "api.php?$qs" ) . ' ' .
                        Html::rawElement( 'a', [ 'href' => $sandbox ],
                            $context->msg( 'api-help-open-in-apisandbox' )->parse() )
                    );
                }
                $help['examples'] .= Html::closeElement( 'dl' );
                $help['examples'] .= Html::closeElement( 'div' );
            }

            $subtocnumber = $tocnumber;
            $subtocnumber[$level + 1] = 0;
            $suboptions = [
                'submodules' => $options['recursivesubmodules'],
                'headerlevel' => $level + 1,
                'tocnumber' => &$subtocnumber,
                'noheader' => false,
            ] + $options;

            if ( $options['submodules'] && $module->getModuleManager() ) {
                $manager = $module->getModuleManager();
                $submodules = [];
                foreach ( $groups as $group ) {
                    $names = $manager->getNames( $group );
                    sort( $names );
                    foreach ( $names as $name ) {
                        $submodules[] = $manager->getModule( $name );
                    }
                }
                $help['submodules'] .= self::getHelpInternal(
                    $context,
                    $submodules,
                    $suboptions,
                    $haveModules
                );
            }

            $module->modifyHelp( $help, $suboptions, $haveModules );

            Hooks::run( 'APIHelpModifyOutput', [ $module, &$help, $suboptions, &$haveModules ] );

            $out .= implode( "\n", $help );
        }

        return $out;
    }

    public function shouldCheckMaxlag() {
        return false;
    }

    public function isReadMode() {
        return false;
    }

    public function getCustomPrinter() {
        $params = $this->extractRequestParams();
        if ( $params['wrap'] ) {
            return null;
        }

        $main = $this->getMain();
        $errorPrinter = $main->createPrinterByName( $main->getParameter( 'format' ) );
        return new ApiFormatRaw( $main, $errorPrinter );
    }

    public function getAllowedParams() {
        return [
            'modules' => [
                ApiBase::PARAM_DFLT => 'main',
                ApiBase::PARAM_ISMULTI => true,
            ],
            'submodules' => false,
            'recursivesubmodules' => false,
            'wrap' => false,
            'toc' => false,
        ];
    }

    protected function getExamplesMessages() {
        return [
            'action=help'
                => 'apihelp-help-example-main',
            'action=help&modules=query&submodules=1'
                => 'apihelp-help-example-submodules',
            'action=help&recursivesubmodules=1'
                => 'apihelp-help-example-recursive',
            'action=help&modules=help'
                => 'apihelp-help-example-help',
            'action=help&modules=query+info|query+categorymembers'
                => 'apihelp-help-example-query',
        ];
    }

    public function getHelpUrls() {
        return [
            'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Main_page',
            'https://www.mediawiki.org/wiki/Special:MyLanguage/API:FAQ',
            'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Quick_start_guide',
        ];
    }
}