mirror of
https://gerrit.wikimedia.org/r/mediawiki/extensions/MultimediaViewer
synced 2024-12-04 20:48:22 +00:00
b02ba00fd0
Bug: T138401 Change-Id: Ib09d471a28821f54c6f8678e788ba85fbd426d35
165 lines
5.5 KiB
JavaScript
165 lines
5.5 KiB
JavaScript
/*
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* This file is part of the MediaWiki extension MultimediaViewer.
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*
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* MultimediaViewer is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* MultimediaViewer is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with MultimediaViewer. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* Base class for API-based data providers.
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*
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* @abstract
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*/
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class Api {
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/**
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* @param {mw.Api} api
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* @param {Object} [options]
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* @param {number} [options.maxage] cache expiration time, in seconds
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* Will be used for both client-side cache (maxage) and reverse proxies (s-maxage)
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*/
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constructor( api, options ) {
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/**
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* API object for dependency injection.
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*
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* @property {mw.Api}
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*/
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this.api = api;
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/**
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* Options object; the exact format and meaning is unspecified and could be different
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* from subclass to subclass.
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*
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* @property {Object}
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*/
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this.options = options || {};
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/**
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* API call cache.
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*
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* @property {Object.<string, jQuery.Promise>} cache
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* @protected
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*/
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this.cache = {};
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}
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/**
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* Wraps a caching layer around a function returning a promise; if getCachedPromise has been
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* called with the same key already, it will return the previous result.
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*
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* Since it is the promise and not the API response that gets cached, this method can ensure
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* that there are no race conditions and multiple calls to the same resource: even if the
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* request is still in progress, separate calls (with the same key) to getCachedPromise will
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* share on the same promise object.
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* The promise is cached even if it is rejected, so if the API request fails, all later calls
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* to getCachedPromise will fail immediately without retrying the request.
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*
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* @param {string} key cache key
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* @param {function(): jQuery.Promise} getPromise a function to get the promise on cache miss
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* @return {jQuery.Promise}
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*/
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getCachedPromise( key, getPromise ) {
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if ( !this.cache[ key ] ) {
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this.cache[ key ] = getPromise();
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this.cache[ key ].fail( ( error ) => {
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// constructor.name is usually not reliable in inherited classes, but OOjs fixes that
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mw.log( `${ this.constructor.name } provider failed to load: `, error );
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} );
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}
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return this.cache[ key ];
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}
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/**
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* Calls mw.Api.get, with caching parameters.
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*
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* @param {Object} params Parameters to the API query.
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* @param {Object} [ajaxOptions] ajaxOptions argument for mw.Api.get
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* @param {number|null} [maxage] Cache the call for this many seconds.
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* Sets both the maxage (client-side) and smaxage (proxy-side) caching parameters.
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* Null means no caching. Undefined means the default caching period is used.
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* @return {jQuery.Promise} the return value from mw.Api.get
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*/
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apiGetWithMaxAge( params, ajaxOptions, maxage ) {
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if ( maxage === undefined ) {
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maxage = this.options.maxage;
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}
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if ( maxage ) {
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params.maxage = params.smaxage = maxage;
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}
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return this.api.get( params, ajaxOptions );
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}
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/**
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* Pulls an error message out of an API response.
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*
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* @param {Object} data
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* @param {Object} data.error
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* @param {string} data.error.code
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* @param {string} data.error.info
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* @return {string} From data.error.code + ': ' + data.error.info, or 'unknown error'
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*/
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getErrorMessage( data ) {
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const errorCode = data.error && data.error.code;
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let errorMessage = data.error && data.error.info || 'unknown error';
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if ( errorCode ) {
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errorMessage = `${ errorCode }: ${ errorMessage }`;
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}
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return errorMessage;
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}
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/**
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* Returns a promise with the specified field from the API result.
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* This is intended to be used as a .then() callback for action=query APIs.
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*
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* @param {string} field
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* @param {Object} data
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* @return {jQuery.Promise} when successful, the first argument will be the field data,
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* when unsuccessful, it will be an error message. The second argument is always
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* the full API response.
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*/
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getQueryField( field, data ) {
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if ( data && data.query && data.query[ field ] ) {
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return $.Deferred().resolve( data.query[ field ], data );
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} else {
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return $.Deferred().reject( this.getErrorMessage( data ), data );
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}
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}
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/**
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* Returns a promise with the specified page from the API result.
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* This is intended to be used as a .then() callback for action=query&prop=(...) APIs.
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*
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* @param {Object} data
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* @return {jQuery.Promise} when successful, the first argument will be the page data,
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* when unsuccessful, it will be an error message. The second argument is always
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* the full API response.
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*/
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getQueryPage( data ) {
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if ( data &&
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data.query &&
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Array.isArray( data.query.pages ) &&
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data.query.pages.length === 1
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) {
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// pages is an array and the first element is always the requested title
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return $.Deferred().resolve( data.query.pages[ 0 ], data );
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}
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// If we got to this point either the pages array is missing completely, or the
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// first element is not the requested page. Neither is supposed to happen
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// (if the page simply did not exist, there would still be a record for it).
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return $.Deferred().reject( this.getErrorMessage( data ), data );
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}
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}
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module.exports = Api;
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