themes/base: xhr.js: clean code style, implement XHR.get() and XHR.poll() convenience functions

themes/base/htdocs/luci-static/resources/xhr.js

@@ -7,10 +7,10 @@ XHR = function()
 {
 	this.reinit = function()
 	{
-		if( window.XMLHttpRequest ) {
+		if (window.XMLHttpRequest) {
 			this._xmlHttp = new XMLHttpRequest();
 		}
-		else if( window.ActiveXObject ) {
+		else if (window.ActiveXObject) {
 			this._xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
 		}
 		else {
@@ -19,7 +19,10 @@ XHR = function()
 	}
 
 	this.busy = function() {
-		switch( this._xmlHttp.readyState )
+		if (!this._xmlHttp)
+			return false;
+
+		switch (this._xmlHttp.readyState)
 		{
 			case 1:
 			case 2:
@@ -32,7 +35,7 @@ XHR = function()
 	}
 
 	this.abort = function() {
-		if( this.busy() )
+		if (this.busy())
 			this._xmlHttp.abort();
 	}
 
@@ -41,23 +44,23 @@ XHR = function()
 		this.reinit();
 
 		var xhr  = this._xmlHttp;
-		var code = this._encode( data );
+		var code = this._encode(data);
 
 		url = location.protocol + '//' + location.host + url;
 
-		if( code )
-			if( url.substr(url.length-1,1) == '&' )
+		if (code)
+			if (url.substr(url.length-1,1) == '&')
 				url += code;
 			else
 				url += '?' + code;
 
-		xhr.open( 'GET', url, true );
+		xhr.open('GET', url, true);
 
 		xhr.onreadystatechange = function()
 		{
-			if( xhr.readyState == 4 ) {
+			if (xhr.readyState == 4) {
 				var json = null;
-				if( xhr.getResponseHeader("Content-Type") == "application/json" ) {
+				if (xhr.getResponseHeader("Content-Type") == "application/json") {
 					try {
 						json = eval('(' + xhr.responseText + ')');
 					}
@@ -66,11 +69,11 @@ XHR = function()
 					}
 				}
 
-				callback( xhr, json );
+				callback(xhr, json);
 			}
 		}
 
-		xhr.send( null );
+		xhr.send(null);
 	}
 
 	this.post = function(url,data,callback)
@@ -78,19 +81,19 @@ XHR = function()
 		this.reinit();
 
 		var xhr  = this._xmlHttp;
-		var code = this._encode( data );
+		var code = this._encode(data);
 
 		xhr.onreadystatechange = function()
 		{
-			if( xhr.readyState == 4 )
-				callback( xhr );
+			if (xhr.readyState == 4)
+				callback(xhr);
 		}
 
-		xhr.open( 'POST', url, true );
-		xhr.setRequestHeader( 'Content-type', 'application/x-www-form-urlencoded' );
-		xhr.setRequestHeader( 'Content-length', code.length );
-		xhr.setRequestHeader( 'Connection', 'close' );
-		xhr.send( code );
+		xhr.open('POST', url, true);
+		xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
+		xhr.setRequestHeader('Content-length', code.length);
+		xhr.setRequestHeader('Connection', 'close');
+		xhr.send(code);
 	}
 
 	this.cancel = function()
@@ -103,41 +106,41 @@ XHR = function()
 	{
 		var code = '';
 
-		for( var i = 0; i < form.elements.length; i++ )
+		for (var i = 0; i < form.elements.length; i++)
 		{
 			var e = form.elements[i];
 
-			if( e.options )
+			if (e.options)
 			{
-				code += ( code ? '&' : '' ) +
+				code += (code ? '&' : '') +
 					form.elements[i].name + '=' + encodeURIComponent(
 						e.options[e.selectedIndex].value
 					);
 			}
-			else if( e.length )
+			else if (e.length)
 			{
-				for( var j = 0; j < e.length; j++ )
-					if( e[j].name ) {
-						code += ( code ? '&' : '' ) +
-							e[j].name + '=' + encodeURIComponent( e[j].value );
+				for (var j = 0; j < e.length; j++)
+					if (e[j].name) {
+						code += (code ? '&' : '') +
+							e[j].name + '=' + encodeURIComponent(e[j].value);
 					}
 			}
 			else
 			{
-				code += ( code ? '&' : '' ) +
-					e.name + '=' + encodeURIComponent( e.value );
+				code += (code ? '&' : '') +
+					e.name + '=' + encodeURIComponent(e.value);
 			}
 		}
 
-		if( typeof extra_values == 'object' )
-			for( var key in extra_values )
-				code += ( code ? '&' : '' ) +
-					key + '=' + encodeURIComponent( extra_values[key] );
+		if (typeof extra_values == 'object')
+			for (var key in extra_values)
+				code += (code ? '&' : '') +
+					key + '=' + encodeURIComponent(extra_values[key]);
 
 		return(
-			( form.method == 'get' )
-				? this.get( form.getAttribute('action'), code, callback )
-				: this.post( form.getAttribute('action'), code, callback )
+			(form.method == 'get')
+				? this.get(form.getAttribute('action'), code, callback)
+				: this.post(form.getAttribute('action'), code, callback)
 		);
 	}
 
@@ -146,14 +149,14 @@ XHR = function()
 		obj = obj ? obj : { };
 		obj['_'] = Math.random();
 
-		if( typeof obj == 'object' )
+		if (typeof obj == 'object')
 		{
 			var code = '';
 			var self = this;
 
-			for( var k in obj )
-				code += ( code ? '&' : '' ) +
-					k + '=' + encodeURIComponent( obj[k] );
+			for (var k in obj)
+				code += (code ? '&' : '') +
+					k + '=' + encodeURIComponent(obj[k]);
 
 			return code;
 		}
@@ -161,3 +164,41 @@ XHR = function()
 		return obj;
 	}
 }
+
+XHR.get = function(url, data, callback)
+{
+	(new XHR()).get(url, data, callback);
+}
+
+XHR.poll = function(interval, url, data, callback)
+{
+	if (isNaN(interval) || interval <= 1)
+		interval = 5;
+
+	if (!XHR._q)
+	{
+		XHR._t = 0;
+		XHR._q = [ ];
+	}
+
+	XHR._q.push({
+		interval: interval,
+		callback: callback,
+		url:      url,
+		data:     data,
+		xhr:      new XHR()
+	});
+
+	if (!XHR._i)
+	{
+		XHR._i = window.setInterval(function() {
+			for (var i = 0, e = XHR._q[0]; i < XHR._q.length; e = XHR._q[++i])
+			{
+				if (!(XHR._t % e.interval) && !e.xhr.busy())
+					e.xhr.get(e.url, e.data, e.callback);
+			}
+
+			XHR._t++;
+		}, 1000);
+	}
+}