mediawiki-extensions-Visual.../api/ParserService.js

/**
 * A very basic parser / serializer web service.
 */

var express = require('express'),
	jsDiff = require('diff'),
	html5 = require('html5');

var mp = '../modules/parser/';

var ParserPipelineFactory = require(mp + 'mediawiki.parser.js').ParserPipelineFactory,
	ParserEnv = require(mp + 'mediawiki.parser.environment.js').MWParserEnvironment,
	WikitextSerializer = require(mp + 'mediawiki.WikitextSerializer.js').WikitextSerializer,
	TemplateRequest = require(mp + 'mediawiki.ApiRequest.js').TemplateRequest;


var env = new ParserEnv( {
	// fetch templates from enwiki for now..
	wgScript: 'http://en.wikipedia.org/w',
	// stay within the 'proxied' content, so that we can click around
	wgScriptPath: '/', //http://en.wikipedia.org/wiki',
	wgScriptExtension: '.php',
	// XXX: add options for this!
	wgUploadPath: 'http://upload.wikimedia.org/wikipedia/commons',
	fetchTemplates: true,
	// enable/disable debug output using this switch
	debug: false,
	trace: false,
	maxDepth: 40,
	interwikis:
"en|de|fr|nl|it|pl|es|ru|ja|pt|zh|sv|vi|uk|ca|no|fi|cs|hu|ko|fa|id|tr|ro|ar|sk|eo|da|sr|lt|ms|eu|he|sl|bg|kk|vo|war|hr|hi|et|az|gl|simple|nn|la|th|el|new|roa-rup|oc|sh|ka|mk|tl|ht|pms|te|ta|be-x-old|ceb|br|be|lv|sq|jv|mg|cy|lb|mr|is|bs|yo|an|hy|fy|bpy|lmo|pnb|ml|sw|bn|io|af|gu|zh-yue|ne|nds|ku|ast|ur|scn|su|qu|diq|ba|tt|my|ga|cv|ia|nap|bat-smg|map-bms|wa|kn|als|am|bug|tg|gd|zh-min-nan|yi|vec|hif|sco|roa-tara|os|arz|nah|uz|sah|mn|sa|mzn|pam|hsb|mi|li|ky|si|co|gan|glk|ckb|bo|fo|bar|bcl|ilo|mrj|fiu-vro|nds-nl|tk|vls|se|gv|ps|rue|dv|nrm|pag|koi|pa|rm|km|kv|udm|csb|mhr|fur|mt|wuu|lij|ug|lad|pi|zea|sc|bh|zh-classical|nov|ksh|or|ang|kw|so|nv|xmf|stq|hak|ay|frp|frr|ext|szl|pcd|ie|gag|haw|xal|ln|rw|pdc|pfl|krc|crh|eml|ace|gn|to|ce|kl|arc|myv|dsb|vep|pap|bjn|as|tpi|lbe|wo|mdf|jbo|kab|av|sn|cbk-zam|ty|srn|kbd|lo|ab|lez|mwl|ltg|ig|na|kg|tet|za|kaa|nso|zu|rmy|cu|tn|chr|got|sm|bi|mo|bm|iu|chy|ik|pih|ss|sd|pnt|cdo|ee|ha|ti|bxr|om|ks|ts|ki|ve|sg|rn|dz|cr|lg|ak|tum|fj|st|tw|ch|ny|ff|xh|ng|ii|cho|mh|aa|kj|ho|mus|kr|hz"
} );


var parserPipelineFactory = new ParserPipelineFactory( env );
//var parser = parserPipelineFactory.makePipeline( 'text/x-mediawiki/full' );


var app = express.createServer();
app.use(express.bodyParser());

app.get('/', function(req, res){
	res.write('<body><h3>Welcome to the alpha test web service for the ' +
		'<a href="http://www.mediawiki.org/wiki/Parsoid">Parsoid project<a>.</h3>');
	res.write( '<p>Usage: <ul><li>GET /title for the DOM. ' +
		'Example: <strong><a href="/Main_Page">Main Page</a></strong>');
	res.write('<li>POST a DOM as parameter "content" to /title for the wikitext</ul>');
	res.write('<p>There are also some tools for experiments:<ul>');
	res.write('<li>Round-trip test pages from the English Wikipedia: ' +
		'<strong><a href="/_rt/Help:Magic">/_rt/Help:Magic</a></strong></li>');
	res.write('<li><strong><a href="/_rtform/">WikiText -&gt; HTML DOM -&gt; WikiText round-trip form</a></strong></li>');
	res.write('<li><strong><a href="/_wikitext/">WikiText -&gt; HTML DOM form</a></strong></li>' +
			'<li><strong><a href="/_html/">HTML DOM -&gt; WikiText form</a></strong></li>');
	res.end('</ul>');
});

var htmlSpecialChars = function ( s ) {
	return s.replace(/&/g,'&amp;')
		.replace(/</g,'&lt;')
		.replace(/"/g,'&quot;')
		.replace(/'/g,'&#039;');
};

var textarea = function ( res, content ) {
	res.write('<form method=POST><textarea name="content" cols=90 rows=9>');
	res.write( ( content &&
					htmlSpecialChars( content) ) ||
			'');
	res.write('</textarea><br><input type="submit"></form>');
};


/**
 * Form-based HTML DOM -> wikitext interface for manual testing
 */
app.get(/\/_html\/(.*)/, function(req, res){
	env.pageName = req.params[0];
	res.setHeader('Content-Type', 'text/html; charset=UTF-8');
	res.write( "Your HTML DOM:" );
	textarea( res );
	res.end('');
});
app.post(/\/_html\/(.*)/, function(req, res){
	env.pageName = req.params[0];
	res.setHeader('Content-Type', 'text/html; charset=UTF-8');
	var p = new html5.Parser();
	p.parse( '<html><body>' + req.body.content + '</body></html>' );
	res.write('<pre style="background-color: #efefef">');
	new WikitextSerializer({env: env}).serializeDOM(
		p.tree.document.childNodes[0].childNodes[1],
		function( c ) {
			res.write( htmlSpecialChars( c ) );
		});
	res.write('</pre>');
	res.write( "<hr>Your HTML DOM:" );
	textarea( res, req.body.content );
	res.end('');
});

/**
 * Form-based wikitext -> HTML DOM interface for manual testing
 */
app.get(/\/_wikitext\/(.*)/, function(req, res){
	env.pageName = req.params[0];
	res.setHeader('Content-Type', 'text/html; charset=UTF-8');
	res.write( "Your wikitext:" );
	textarea( res );
	res.end('');
});
app.post(/\/_wikitext\/(.*)/, function(req, res){
	env.pageName = req.params[0];
	res.setHeader('Content-Type', 'text/html; charset=UTF-8');
	var parser = parserPipelineFactory.makePipeline( 'text/x-mediawiki/full' );
	parser.on('document', function ( document ) {
		res.write(document.body.innerHTML);
		//res.write('<form method=POST><input name="content"></form>');
		//res.end("hello world\n" + req.method + ' ' + req.params.title);
		res.write( "<hr>Your wikitext:" );
		textarea( res, req.body.content );
		res.end('');
	});
	try {
		res.setHeader('Content-Type', 'text/html; charset=UTF-8');
		console.log('starting parsing of ' + req.params[0]);
		// FIXME: This does not handle includes or templates correctly
		parser.process( req.body.content );
	} catch (e) {
		console.log( e );
		res.write( e );
	}
});

/**
 * Perform word-based diff on a line-based diff. The word-based algorithm is
 * practically unusable for inputs > 5k bytes, so we only perform it on the
 * output of the more efficient line-based diff.
 */
var refineDiff = function( diff ) {
	// Attempt to accumulate consecutive add-delete pairs
	// with short text separating them (short = 2 chars right now)
	//
	// This is equivalent to the <b><i> ... </i></b> minimization
	// to expand range of <b> and <i> tags, except there is no optimal
	// solution except as determined by heuristics ("short text" = <= 2 chars).
	function mergeConsecutiveSegments(wordDiffs) {
		var n        = wordDiffs.length;
		var currIns  = null, currDel = null;
		var newDiffs = [];
		for (var i = 0; i < n; i++) {
			var d = wordDiffs[i];
			if (d.added) {
				// Attempt to accumulate
				if (currIns === null) {
					currIns = d;
				} else {
					currIns.value = currIns.value + d.value;
				}
			} else if (d.removed) {
				// Attempt to accumulate
				if (currDel === null) {
					currDel = d;
				} else {
					currDel.value = currDel.value + d.value;
				}
			} else if ((d.value.length < 3) && currIns && currDel) {
				// Attempt to accumulate
				currIns.value = currIns.value + d.value;
				currDel.value = currDel.value + d.value;
			} else {
				// Accumulation ends. Purge!
				if (currIns !== null) {
					newDiffs.push(currIns);
					currIns = null;
				}
				if (currDel !== null) {
					newDiffs.push(currDel);
					currDel = null;
				}
				newDiffs.push(d);
			}
		}

		// Purge buffered diffs
		if (currIns !== null) newDiffs.push(currIns);
		if (currDel !== null) newDiffs.push(currDel);

		return newDiffs;
	}

	var added = null,
		out = [];
	for ( var i = 0, l = diff.length; i < l; i++ ) {
		var d = diff[i];
		if ( d.added ) {
			if ( added ) {
				out.push( added );
			}
			added = d;
		} else if ( d.removed ) {
			if ( added ) {
				var fineDiff = jsDiff.diffWords( d.value, added.value );
				fineDiff = mergeConsecutiveSegments(fineDiff);
				out.push.apply( out, fineDiff );
				added = null;
			} else {
				out.push( d );
			}
		} else {
			if ( added ) {
				out.push( added );
				added = null;
			}
			out.push(d);
		}
	}
	if ( added ) {
		out.push(added);
	}
	return out;
};

var roundTripDiff = function ( res, src, document ) {
	res.write('<html><head><style>ins { background: #ff9191; text-decoration: none; } del { background: #99ff7e; text-decoration: none }; </style></head><body>');
	res.write( '<h2>Wikitext parsed to HTML DOM</h2><hr>' );
	res.write(document.body.innerHTML + '<hr>');
	res.write( '<h2>HTML DOM converted back to Wikitext</h2><hr>' );
	var out = new WikitextSerializer({env: env}).serializeDOM( document.body );
	res.write('<pre>' + htmlSpecialChars( out ) + '</pre><hr>');
	res.write( '<h2>Diff between original Wikitext (green) and round-tripped wikitext (red)</h2><hr>' );
	var patch;
	if ( src.length < 4000 ) {
		// Use word-based diff for small articles
		patch = jsDiff.convertChangesToXML( jsDiff.diffWords( src, out ) );
	} else {
		//console.log(JSON.stringify( jsDiff.diffLines( out, src ) ));
		//patch = jsDiff.convertChangesToXML( jsDiff.diffLines( out, src ) );
		patch = jsDiff.convertChangesToXML( refineDiff( jsDiff.diffLines( src, out ) ) );
	}
	res.end( '<pre>' + patch);
};

var parse = function ( res, cb, src ) {
	var parser = parserPipelineFactory.makePipeline( 'text/x-mediawiki/full' );
	parser.on('document', cb.bind( null, res, src ) );
	try {
		res.setHeader('Content-Type', 'text/html; charset=UTF-8');
		parser.process( src );
	} catch (e) {
		console.log( e );
		res.end( e );
	}
};

/**
 * Round-trip article testing
 */
app.get( new RegExp('/_rt/(?:(?:(?:' + env.interwikis + '):)?(' + env.interwikis + '):)?(.*)') , function(req, res){
	env.pageName = req.params[1];
	if ( req.params[0] ) {
		env.wgScriptPath = '/_rt/' + req.params[0] + ':';
		env.wgScript = 'http://' + req.params[0] + '.wikipedia.org/w';
	} else {
		// default to English Wikipedia
		env.wgScriptPath = '/_rt/';
		env.wgScript = 'http://en.wikipedia.org/w';
	}

	if ( env.pageName === 'favicon.ico' ) {
		res.end( 'no favicon yet..' );
		return;
	}

	var target = env.resolveTitle( env.normalizeTitle( env.pageName ), '' );

	console.log('starting parsing of ' + target);
	var tpr = new TemplateRequest( env, target );
	tpr.once('src', parse.bind( null, res, roundTripDiff ));
});

/**
 * Form-based round-tripping for manual testing
 */
app.get(/\/_rtform\/(.*)/, function(req, res){
	env.pageName = req.params[0];
	res.setHeader('Content-Type', 'text/html; charset=UTF-8');
	res.write( "Your wikitext:" );
	textarea( res );
	res.end('');
});
app.post(/\/_rtform\/(.*)/, function(req, res){
	env.pageName = req.params[0];
	res.setHeader('Content-Type', 'text/html; charset=UTF-8');
	var parser = parserPipelineFactory.makePipeline( 'text/x-mediawiki/full' );

	parse( res, roundTripDiff, req.body.content);
});

/**
 * Regular article parsing
 */
app.get(new RegExp( '/(?:(?:(?:' + env.interwikis + '):)?(' + env.interwikis + '):)?(.*)' ), function(req, res){
	env.pageName = req.params[1];
	if ( req.params[0] ) {
		env.wgScriptPath = '/' + req.params[0] + ':';
		env.wgScript = 'http://' + req.params[0] + '.wikipedia.org/w';
	} else {
		// default to English Wikipedia
		env.wgScriptPath = '/';
		env.wgScript = 'http://en.wikipedia.org/w';
	}
	if ( env.pageName === 'favicon.ico' ) {
		res.end( 'no favicon yet..');
		return;
	}
	var target = env.resolveTitle( env.normalizeTitle( env.pageName ), '' );

	console.log('starting parsing of ' + target);
	var tpr = new TemplateRequest( env, target );
	tpr.once('src', parse.bind( null, res, function ( res, src, document ) {
		res.end(document.body.innerHTML);
	}));
});

/**
 * Regular article serialization using POST
 */
app.post(/\/(.*)/, function(req, res){
	env.pageName = req.params[0];
	env.wgScriptPath = '/';
	res.setHeader('Content-Type', 'text/x-mediawiki; charset=UTF-8');
	var p = new html5.Parser();
	p.parse( req.body.content );
	new WikitextSerializer({env: env}).serializeDOM(
		p.tree.document.childNodes[0].childNodes[1],
		res.write.bind( res ) );
	res.end('');
});

module.exports = app;