ApiComparePages.php

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<?php
class ApiComparePages extends ApiBase {
 
    private $guessed = false, $guessedTitle, $guessedModel, $props;
 
    public function execute() {
        $params = $this->extractRequestParams();
 
        // Parameter validation
        $this->requireAtLeastOneParameter( $params, 'fromtitle', 'fromid', 'fromrev', 'fromtext' );
        $this->requireAtLeastOneParameter( $params, 'totitle', 'toid', 'torev', 'totext', 'torelative' );
 
        $this->props = array_flip( $params['prop'] );
 
        // Cache responses publicly by default. This may be overridden later.
        $this->getMain()->setCacheMode( 'public' );
 
        // Get the 'from' Revision and Content
        list( $fromRev, $fromContent, $relRev ) = $this->getDiffContent( 'from', $params );
 
        // Get the 'to' Revision and Content
        if ( $params['torelative'] !== null ) {
            if ( !$relRev ) {
                $this->dieWithError( 'apierror-compare-relative-to-nothing' );
            }
            switch ( $params['torelative'] ) {
                case 'prev':
                    // Swap 'from' and 'to'
                    $toRev = $fromRev;
                    $toContent = $fromContent;
                    $fromRev = $relRev->getPrevious();
                    $fromContent = $fromRev
                        ? $fromRev->getContent( Revision::FOR_THIS_USER, $this->getUser() )
                        : $toContent->getContentHandler()->makeEmptyContent();
                    if ( !$fromContent ) {
                        $this->dieWithError(
                            [ 'apierror-missingcontent-revid', $fromRev->getId() ], 'missingcontent'
                        );
                    }
                    break;
 
                case 'next':
                    $toRev = $relRev->getNext();
                    $toContent = $toRev
                        ? $toRev->getContent( Revision::FOR_THIS_USER, $this->getUser() )
                        : $fromContent;
                    if ( !$toContent ) {
                        $this->dieWithError( [ 'apierror-missingcontent-revid', $toRev->getId() ], 'missingcontent' );
                    }
                    break;
 
                case 'cur':
                    $title = $relRev->getTitle();
                    $id = $title->getLatestRevID();
                    $toRev = $id ? Revision::newFromId( $id ) : null;
                    if ( !$toRev ) {
                        $this->dieWithError(
                            [ 'apierror-missingrev-title', wfEscapeWikiText( $title->getPrefixedText() ) ], 'nosuchrevid'
                        );
                    }
                    $toContent = $toRev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
                    if ( !$toContent ) {
                        $this->dieWithError( [ 'apierror-missingcontent-revid', $toRev->getId() ], 'missingcontent' );
                    }
                    break;
            }
            $relRev2 = null;
        } else {
            list( $toRev, $toContent, $relRev2 ) = $this->getDiffContent( 'to', $params );
        }
 
        // Should never happen, but just in case...
        if ( !$fromContent || !$toContent ) {
            $this->dieWithError( 'apierror-baddiff' );
        }
 
        // Extract sections, if told to
        if ( isset( $params['fromsection'] ) ) {
            $fromContent = $fromContent->getSection( $params['fromsection'] );
            if ( !$fromContent ) {
                $this->dieWithError(
                    [ 'apierror-compare-nosuchfromsection', wfEscapeWikiText( $params['fromsection'] ) ],
                    'nosuchfromsection'
                );
            }
        }
        if ( isset( $params['tosection'] ) ) {
            $toContent = $toContent->getSection( $params['tosection'] );
            if ( !$toContent ) {
                $this->dieWithError(
                    [ 'apierror-compare-nosuchtosection', wfEscapeWikiText( $params['tosection'] ) ],
                    'nosuchtosection'
                );
            }
        }
 
        // Get the diff
        $context = new DerivativeContext( $this->getContext() );
        if ( $relRev && $relRev->getTitle() ) {
            $context->setTitle( $relRev->getTitle() );
        } elseif ( $relRev2 && $relRev2->getTitle() ) {
            $context->setTitle( $relRev2->getTitle() );
        } else {
            $this->guessTitleAndModel();
            if ( $this->guessedTitle ) {
                $context->setTitle( $this->guessedTitle );
            }
        }
        $de = $fromContent->getContentHandler()->createDifferenceEngine(
            $context,
            $fromRev ? $fromRev->getId() : 0,
            $toRev ? $toRev->getId() : 0,
            /* $rcid = */ null,
            /* $refreshCache = */ false,
            /* $unhide = */ true
        );
        $de->setContent( $fromContent, $toContent );
        $difftext = $de->getDiffBody();
        if ( $difftext === false ) {
            $this->dieWithError( 'apierror-baddiff' );
        }
 
        // Fill in the response
        $vals = [];
        $this->setVals( $vals, 'from', $fromRev );
        $this->setVals( $vals, 'to', $toRev );
 
        if ( isset( $this->props['rel'] ) ) {
            if ( $fromRev ) {
                $rev = $fromRev->getPrevious();
                if ( $rev ) {
                    $vals['prev'] = $rev->getId();
                }
            }
            if ( $toRev ) {
                $rev = $toRev->getNext();
                if ( $rev ) {
                    $vals['next'] = $rev->getId();
                }
            }
        }
 
        if ( isset( $this->props['diffsize'] ) ) {
            $vals['diffsize'] = strlen( $difftext );
        }
        if ( isset( $this->props['diff'] ) ) {
            ApiResult::setContentValue( $vals, 'body', $difftext );
        }
 
        // Diffs can be really big and there's little point in having
        // ApiResult truncate it to an empty response since the diff is the
        // whole reason this module exists. So pass NO_SIZE_CHECK here.
        $this->getResult()->addValue( null, $this->getModuleName(), $vals, ApiResult::NO_SIZE_CHECK );
    }
 
    private function guessTitleAndModel() {
        if ( $this->guessed ) {
            return;
        }
 
        $this->guessed = true;
        $params = $this->extractRequestParams();
 
        foreach ( [ 'from', 'to' ] as $prefix ) {
            if ( $params["{$prefix}rev"] !== null ) {
                $revId = $params["{$prefix}rev"];
                $rev = Revision::newFromId( $revId );
                if ( !$rev ) {
                    // Titles of deleted revisions aren't secret, per T51088
                    $arQuery = Revision::getArchiveQueryInfo();
                    $row = $this->getDB()->selectRow(
                        $arQuery['tables'],
                        array_merge(
                            $arQuery['fields'],
                            [ 'ar_namespace', 'ar_title' ]
                        ),
                        [ 'ar_rev_id' => $revId ],
                        __METHOD__,
                        [],
                        $arQuery['joins']
                    );
                    if ( $row ) {
                        $rev = Revision::newFromArchiveRow( $row );
                    }
                }
                if ( $rev ) {
                    $this->guessedTitle = $rev->getTitle();
                    $this->guessedModel = $rev->getContentModel();
                    break;
                }
            }
 
            if ( $params["{$prefix}title"] !== null ) {
                $title = Title::newFromText( $params["{$prefix}title"] );
                if ( $title && !$title->isExternal() ) {
                    $this->guessedTitle = $title;
                    break;
                }
            }
 
            if ( $params["{$prefix}id"] !== null ) {
                $title = Title::newFromID( $params["{$prefix}id"] );
                if ( $title ) {
                    $this->guessedTitle = $title;
                    break;
                }
            }
        }
 
        if ( !$this->guessedModel ) {
            if ( $this->guessedTitle ) {
                $this->guessedModel = $this->guessedTitle->getContentModel();
            } elseif ( $params['fromcontentmodel'] !== null ) {
                $this->guessedModel = $params['fromcontentmodel'];
            } elseif ( $params['tocontentmodel'] !== null ) {
                $this->guessedModel = $params['tocontentmodel'];
            }
        }
    }
 
    private function getDiffContent( $prefix, array $params ) {
        $title = null;
        $rev = null;
        $suppliedContent = $params["{$prefix}text"] !== null;
 
        // Get the revision and title, if applicable
        $revId = null;
        if ( $params["{$prefix}rev"] !== null ) {
            $revId = $params["{$prefix}rev"];
        } elseif ( $params["{$prefix}title"] !== null || $params["{$prefix}id"] !== null ) {
            if ( $params["{$prefix}title"] !== null ) {
                $title = Title::newFromText( $params["{$prefix}title"] );
                if ( !$title || $title->isExternal() ) {
                    $this->dieWithError(
                        [ 'apierror-invalidtitle', wfEscapeWikiText( $params["{$prefix}title"] ) ]
                    );
                }
            } else {
                $title = Title::newFromID( $params["{$prefix}id"] );
                if ( !$title ) {
                    $this->dieWithError( [ 'apierror-nosuchpageid', $params["{$prefix}id"] ] );
                }
            }
            $revId = $title->getLatestRevID();
            if ( !$revId ) {
                $revId = null;
                // Only die here if we're not using supplied text
                if ( !$suppliedContent ) {
                    if ( $title->exists() ) {
                        $this->dieWithError(
                            [ 'apierror-missingrev-title', wfEscapeWikiText( $title->getPrefixedText() ) ], 'nosuchrevid'
                        );
                    } else {
                        $this->dieWithError(
                            [ 'apierror-missingtitle-byname', wfEscapeWikiText( $title->getPrefixedText() ) ],
                            'missingtitle'
                        );
                    }
                }
            }
        }
        if ( $revId !== null ) {
            $rev = Revision::newFromId( $revId );
            if ( !$rev && $this->getUser()->isAllowedAny( 'deletedtext', 'undelete' ) ) {
                // Try the 'archive' table
                $arQuery = Revision::getArchiveQueryInfo();
                $row = $this->getDB()->selectRow(
                    $arQuery['tables'],
                    array_merge(
                        $arQuery['fields'],
                        [ 'ar_namespace', 'ar_title' ]
                    ),
                    [ 'ar_rev_id' => $revId ],
                    __METHOD__,
                    [],
                    $arQuery['joins']
                );
                if ( $row ) {
                    $rev = Revision::newFromArchiveRow( $row );
                    $rev->isArchive = true;
                }
            }
            if ( !$rev ) {
                $this->dieWithError( [ 'apierror-nosuchrevid', $revId ] );
            }
            $title = $rev->getTitle();
 
            // If we don't have supplied content, return here. Otherwise,
            // continue on below with the supplied content.
            if ( !$suppliedContent ) {
                $content = $rev->getContent( Revision::FOR_THIS_USER, $this->getUser() );
                if ( !$content ) {
                    $this->dieWithError( [ 'apierror-missingcontent-revid', $revId ], 'missingcontent' );
                }
                return [ $rev, $content, $rev ];
            }
        }
 
        // Override $content based on supplied text
        $model = $params["{$prefix}contentmodel"];
        $format = $params["{$prefix}contentformat"];
 
        if ( !$model && $rev ) {
            $model = $rev->getContentModel();
        }
        if ( !$model && $title ) {
            $model = $title->getContentModel();
        }
        if ( !$model ) {
            $this->guessTitleAndModel();
            $model = $this->guessedModel;
        }
        if ( !$model ) {
            $model = CONTENT_MODEL_WIKITEXT;
            $this->addWarning( [ 'apiwarn-compare-nocontentmodel', $model ] );
        }
 
        if ( !$title ) {
            $this->guessTitleAndModel();
            $title = $this->guessedTitle;
        }
 
        try {
            $content = ContentHandler::makeContent( $params["{$prefix}text"], $title, $model, $format );
        } catch ( MWContentSerializationException $ex ) {
            $this->dieWithException( $ex, [
                'wrap' => ApiMessage::create( 'apierror-contentserializationexception', 'parseerror' )
            ] );
        }
 
        if ( $params["{$prefix}pst"] ) {
            if ( !$title ) {
                $this->dieWithError( 'apierror-compare-no-title' );
            }
            $popts = ParserOptions::newFromContext( $this->getContext() );
            $content = $content->preSaveTransform( $title, $this->getUser(), $popts );
        }
 
        return [ null, $content, $rev ];
    }
 
    private function setVals( &$vals, $prefix, $rev ) {
        if ( $rev ) {
            $title = $rev->getTitle();
            if ( isset( $this->props['ids'] ) ) {
                $vals["{$prefix}id"] = $title->getArticleID();
                $vals["{$prefix}revid"] = $rev->getId();
            }
            if ( isset( $this->props['title'] ) ) {
                ApiQueryBase::addTitleInfo( $vals, $title, $prefix );
            }
            if ( isset( $this->props['size'] ) ) {
                $vals["{$prefix}size"] = $rev->getSize();
            }
 
            $anyHidden = false;
            if ( $rev->isDeleted( Revision::DELETED_TEXT ) ) {
                $vals["{$prefix}texthidden"] = true;
                $anyHidden = true;
            }
 
            if ( $rev->isDeleted( Revision::DELETED_USER ) ) {
                $vals["{$prefix}userhidden"] = true;
                $anyHidden = true;
            }
            if ( isset( $this->props['user'] ) &&
                $rev->userCan( Revision::DELETED_USER, $this->getUser() )
            ) {
                $vals["{$prefix}user"] = $rev->getUserText( Revision::RAW );
                $vals["{$prefix}userid"] = $rev->getUser( Revision::RAW );
            }
 
            if ( $rev->isDeleted( Revision::DELETED_COMMENT ) ) {
                $vals["{$prefix}commenthidden"] = true;
                $anyHidden = true;
            }
            if ( $rev->userCan( Revision::DELETED_COMMENT, $this->getUser() ) ) {
                if ( isset( $this->props['comment'] ) ) {
                    $vals["{$prefix}comment"] = $rev->getComment( Revision::RAW );
                }
                if ( isset( $this->props['parsedcomment'] ) ) {
                    $vals["{$prefix}parsedcomment"] = Linker::formatComment(
                        $rev->getComment( Revision::RAW ),
                        $rev->getTitle()
                    );
                }
            }
 
            if ( $anyHidden ) {
                $this->getMain()->setCacheMode( 'private' );
                if ( $rev->isDeleted( Revision::DELETED_RESTRICTED ) ) {
                    $vals["{$prefix}suppressed"] = true;
                }
            }
 
            if ( !empty( $rev->isArchive ) ) {
                $this->getMain()->setCacheMode( 'private' );
                $vals["{$prefix}archive"] = true;
            }
        }
    }
 
    public function getAllowedParams() {
        // Parameters for the 'from' and 'to' content
        $fromToParams = [
            'title' => null,
            'id' => [
                ApiBase::PARAM_TYPE => 'integer'
            ],
            'rev' => [
                ApiBase::PARAM_TYPE => 'integer'
            ],
            'text' => [
                ApiBase::PARAM_TYPE => 'text'
            ],
            'section' => null,
            'pst' => false,
            'contentformat' => [
                ApiBase::PARAM_TYPE => ContentHandler::getAllContentFormats(),
            ],
            'contentmodel' => [
                ApiBase::PARAM_TYPE => ContentHandler::getContentModels(),
            ]
        ];
 
        $ret = [];
        foreach ( $fromToParams as $k => $v ) {
            $ret["from$k"] = $v;
        }
        foreach ( $fromToParams as $k => $v ) {
            $ret["to$k"] = $v;
        }
 
        $ret = wfArrayInsertAfter(
            $ret,
            [ 'torelative' => [ ApiBase::PARAM_TYPE => [ 'prev', 'next', 'cur' ], ] ],
            'torev'
        );
 
        $ret['prop'] = [
            ApiBase::PARAM_DFLT => 'diff|ids|title',
            ApiBase::PARAM_TYPE => [
                'diff',
                'diffsize',
                'rel',
                'ids',
                'title',
                'user',
                'comment',
                'parsedcomment',
                'size',
            ],
            ApiBase::PARAM_ISMULTI => true,
            ApiBase::PARAM_HELP_MSG_PER_VALUE => [],
        ];
 
        return $ret;
    }
 
    protected function getExamplesMessages() {
        return [
            'action=compare&fromrev=1&torev=2'
                => 'apihelp-compare-example-1',
        ];
    }
}