如何合并几个MediaWiki API请求的结果？

Question

I have a small (working) Wikipedia user script that queries the MediaWiki API and then queries it once again for each of the results of the first query, printing the results of the "second level" queries on the console (Firefox 52.0/Linux):

mw.loader.using( [ 'mediawiki.api', 'mediawiki.ForeignApi' ] ).done( function () {
    var api = new mw.Api();
    api.get( {
        action: 'query',
        meta: 'globaluserinfo',
        guiprop: 'merged'
    } ).done( function ( data ) {
        data.query.globaluserinfo.merged.forEach( function( element, index, array ) {
            let url = element.url;
            var remoteapi = new mw.ForeignApi( url + '/w/api.php' );
            [mw.config.get('wgNamespaceIds').user, mw.config.get('wgNamespaceIds').user_talk].forEach( function( element, index, array ) {
                remoteapi.get( {
                    action: 'query',
                    list: 'allpages',
                    apprefix: data.query.globaluserinfo.name,
                    apnamespace: element
                } ).done( function (data2) {
                    for( var j = 0; j < data2.query.allpages.length; j++ )
                        console.log( url + '/wiki/' + data2.query.allpages[j].title );
                });
            } );
        } );
    } );
} );

I now want to replace the individual console outputs with one combined dialog box (à la mw.loader.using( 'oojs-ui-windows' ).done( function () { OO.ui.alert( 'All results: ' + results ); } ); ).

In other words, I want to execute one callback when all API queries have been done, accessing/aggregating/combining the results from all of them. How can that be done?

Answer 1

Parallel requests (same as Tim's answer, just a little more heavy on promises):

mw.loader.using( [ 'mediawiki.api', 'mediawiki.ForeignApi' ] ).done( function () {
    // get all accounts of user
    new mw.Api().get( {
        action: 'query',
        meta: 'globaluserinfo',
        guiprop: 'merged',
        formatversion: 2,
        errorformat: 'wikitext',
        errorsuselocal: true
    } )
    // create a list of needed requests
    .then( function ( data ) {
        return data.query.globaluserinfo.merged.map( function( element, index, array ) {
            let url = element.url;
            let remoteapi = ( url === 'https:' + mw.config.get( 'wgServer' ) )
                ? new mw.Api()
                : new mw.ForeignApi( url + '/w/api.php' );                if (url === 'https:' + mw.config.get('wgServer'));
            let request = {
                action: 'query',
                generator: 'allpages',
                gapprefix: data.query.globaluserinfo.name + '/',
                gaplimit: 'max',
                prop: 'info',
                inprop: 'url'
            };
            return [
                $.extend( { namespace: mw.config.get('wgNamespaceIds').user }, request ),
                $.extend( { namespace: mw.config.get('wgNamespaceIds').user_talk }, request )
            ];
        } );
    } )
    // fire the requests and merge promises
    .then( function ( requests ) {
        var promises = requests.map( function ( request ) {
            return remoteapi.get( request ).then( function ( data ) {
                return $.map( data.query.pages, function( val, key ) {
                    return val.fullurl;
                } );
            } ), function () {
                console.log( 'FAIL = ' + JSON.stringify( arguments ) );
            } );
        } );
        promises.push( mw.loader.using( 'oojs-ui-windows' ) );
        return $.when.apply( $, promises ).then( function ( urls ) {
            // last result is from mw.loader, discard it
            urls.pop();
            return urls;
        } );
    } )
    // business logic
    .done( function ( urls ) {
        OO.ui.alert( 'All results: ' + urls.join( '\n' ) );
    } ).fail( function () {
        OO.ui.alert( 'FAIL!' );
    } );
} );

If you want to limit parallelism (probably a good idea if you have many accounts) you can replace the "fire the requests" block with something like

.then( function ( requests ) {
    var status = Array( requests.length );
    let processNext = function () {
        let index = status.indexOf( undefined );
        if ( index >= 0 ) {
            status[index] = true;
            return remoteapi.get( requests[index] ).then( function ( data ) {
                requests[index] = $.map( data.query.pages, function( val, key ) {
                    return val.fullurl;
                } );
            } ), function () {
                console.log( 'FAIL = ' + JSON.stringify( arguments ) );
            } ).then( processNext, processNext );
        } else {
            return $.Deferred().resolve();
        }
    }
    let queue = Array( 5 ).map( function () {
        processNext();
    } ) );
    queue.push( mw.loader.using( 'oojs-ui-windows' ) );
    return $.when.apply( $, queue ).then( function () {
        return requests;
    } );
} )

(Note that I have done no testing whatsoever. Also, this does not handle continuation, which is too complex to attempt to write code for without testing. Maybe mw.Api does handle it, never checked. In any case, the limit is 500 page per wiki (5000 if you are a local admin) so you should probably be good.)

Answer 2

To wait until all queries have finished, the promises returned by mediawiki.api.get() need to be added to an array, in the following example p . jQuery then offers the $.when() method to execute a callback when all promises given as parameters have been resolved. As the number of them in this case is random, $.when.apply() needs to be used.

mw.loader.using( [ 'mediawiki.api', 'mediawiki.ForeignApi' ] ).done( function () {
    var api = new mw.Api();
    api.get( {
        action: 'query',
        meta: 'globaluserinfo',
        guiprop: 'merged'
    } ).done( function ( data ) {
        var p = [];
        var r = [];
        data.query.globaluserinfo.merged.forEach( function( element, index, array ) {
            let url = element.url;
            if (url === 'https:' + mw.config.get('wgServer'))
                var remoteapi = new mw.Api();
            else
                var remoteapi = new mw.ForeignApi( url + '/w/api.php' );
            [mw.config.get('wgNamespaceIds').user, mw.config.get('wgNamespaceIds').user_talk].forEach( function( element, index, array ) {
                p.push( remoteapi.get( {
                    action: 'query',
                    list: 'allpages',
                    apprefix: data.query.globaluserinfo.name + '/',
                    apnamespace: element
                } ).done( function (data2) {
                    for( var j = 0; j < data2.query.allpages.length; j++ )
                        r.push( url + '/wiki/' + data2.query.allpages[j].title );
                } ).fail( function () {
                    console.log( 'FAIL = ' + JSON.stringify( arguments ) );
                } ) );
            } );
        } );
        $.when.apply($, p).done( function () {
            mw.loader.using( 'oojs-ui-windows' ).done( function () {
                OO.ui.alert( 'All results: ' + r );
            } );
        } ).fail( function () {
            mw.loader.using( 'oojs-ui-windows' ).done( function () {
                OO.ui.alert( 'FAIL!' );
            } );
        } );
    } );
} );