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'use strict';
var utils = require('../../utils/iframe')
, random = require('../../utils/random')
, browser = require('../../utils/browser')
, urlUtils = require('../../utils/url')
, inherits = require('inherits')
, EventEmitter = require('events').EventEmitter
;
var debug = function() {};
if (process.env.NODE_ENV !== 'production') {
debug = require('debug')('sockjs-client:receiver:jsonp');
}
function JsonpReceiver(url) {
debug(url);
var self = this;
EventEmitter.call(this);
utils.polluteGlobalNamespace();
this.id = 'a' + random.string(6);
var urlWithId = urlUtils.addQuery(url, 'c=' + encodeURIComponent(utils.WPrefix + '.' + this.id));
global[utils.WPrefix][this.id] = this._callback.bind(this);
this._createScript(urlWithId);
// Fallback mostly for Konqueror - stupid timer, 35 seconds shall be plenty.
this.timeoutId = setTimeout(function() {
debug('timeout');
self._abort(new Error('JSONP script loaded abnormally (timeout)'));
}, JsonpReceiver.timeout);
}
inherits(JsonpReceiver, EventEmitter);
JsonpReceiver.prototype.abort = function() {
debug('abort');
if (global[utils.WPrefix][this.id]) {
var err = new Error('JSONP user aborted read');
err.code = 1000;
this._abort(err);
}
};
JsonpReceiver.timeout = 35000;
JsonpReceiver.scriptErrorTimeout = 1000;
JsonpReceiver.prototype._callback = function(data) {
debug('_callback', data);
this._cleanup();
if (this.aborting) {
return;
}
if (data) {
debug('message', data);
this.emit('message', data);
}
this.emit('close', null, 'network');
this.removeAllListeners();
};
JsonpReceiver.prototype._abort = function(err) {
debug('_abort', err);
this._cleanup();
this.aborting = true;
this.emit('close', err.code, err.message);
this.removeAllListeners();
};
JsonpReceiver.prototype._cleanup = function() {
debug('_cleanup');
clearTimeout(this.timeoutId);
if (this.script2) {
this.script2.parentNode.removeChild(this.script2);
this.script2 = null;
}
if (this.script) {
var script = this.script;
// Unfortunately, you can't really abort script loading of
// the script.
script.parentNode.removeChild(script);
script.onreadystatechange = script.onerror =
script.onload = script.onclick = null;
this.script = null;
}
delete global[utils.WPrefix][this.id];
};
JsonpReceiver.prototype._scriptError = function() {
debug('_scriptError');
var self = this;
if (this.errorTimer) {
return;
}
this.errorTimer = setTimeout(function() {
if (!self.loadedOkay) {
self._abort(new Error('JSONP script loaded abnormally (onerror)'));
}
}, JsonpReceiver.scriptErrorTimeout);
};
JsonpReceiver.prototype._createScript = function(url) {
debug('_createScript', url);
var self = this;
var script = this.script = global.document.createElement('script');
var script2; // Opera synchronous load trick.
script.id = 'a' + random.string(8);
script.src = url;
script.type = 'text/javascript';
script.charset = 'UTF-8';
script.onerror = this._scriptError.bind(this);
script.onload = function() {
debug('onload');
self._abort(new Error('JSONP script loaded abnormally (onload)'));
};
// IE9 fires 'error' event after onreadystatechange or before, in random order.
// Use loadedOkay to determine if actually errored
script.onreadystatechange = function() {
debug('onreadystatechange', script.readyState);
if (/loaded|closed/.test(script.readyState)) {
if (script && script.htmlFor && script.onclick) {
self.loadedOkay = true;
try {
// In IE, actually execute the script.
script.onclick();
} catch (x) {
// intentionally empty
}
}
if (script) {
self._abort(new Error('JSONP script loaded abnormally (onreadystatechange)'));
}
}
};
// IE: event/htmlFor/onclick trick.
// One can't rely on proper order for onreadystatechange. In order to
// make sure, set a 'htmlFor' and 'event' properties, so that
// script code will be installed as 'onclick' handler for the
// script object. Later, onreadystatechange, manually execute this
// code. FF and Chrome doesn't work with 'event' and 'htmlFor'
// set. For reference see:
// http://jaubourg.net/2010/07/loading-script-as-onclick-handler-of.html
// Also, read on that about script ordering:
// http://wiki.whatwg.org/wiki/Dynamic_Script_Execution_Order
if (typeof script.async === 'undefined' && global.document.attachEvent) {
// According to mozilla docs, in recent browsers script.async defaults
// to 'true', so we may use it to detect a good browser:
// https://developer.mozilla.org/en/HTML/Element/script
if (!browser.isOpera()) {
// Naively assume we're in IE
try {
script.htmlFor = script.id;
script.event = 'onclick';
} catch (x) {
// intentionally empty
}
script.async = true;
} else {
// Opera, second sync script hack
script2 = this.script2 = global.document.createElement('script');
script2.text = "try{var a = document.getElementById('" + script.id + "'); if(a)a.onerror();}catch(x){};";
script.async = script2.async = false;
}
}
if (typeof script.async !== 'undefined') {
script.async = true;
}
var head = global.document.getElementsByTagName('head')[0];
head.insertBefore(script, head.firstChild);
if (script2) {
head.insertBefore(script2, head.firstChild);
}
};
module.exports = JsonpReceiver;