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'use strict';
var EventEmitter = require('events').EventEmitter
, inherits = require('inherits')
, utils = require('../../utils/event')
, urlUtils = require('../../utils/url')
, XHR = global.XMLHttpRequest
;
var debug = function() {};
if (process.env.NODE_ENV !== 'production') {
debug = require('debug')('sockjs-client:browser:xhr');
}
function AbstractXHRObject(method, url, payload, opts) {
debug(method, url);
var self = this;
EventEmitter.call(this);
setTimeout(function () {
self._start(method, url, payload, opts);
}, 0);
}
inherits(AbstractXHRObject, EventEmitter);
AbstractXHRObject.prototype._start = function(method, url, payload, opts) {
var self = this;
try {
this.xhr = new XHR();
} catch (x) {
// intentionally empty
}
if (!this.xhr) {
debug('no xhr');
this.emit('finish', 0, 'no xhr support');
this._cleanup();
return;
}
// several browsers cache POSTs
url = urlUtils.addQuery(url, 't=' + (+new Date()));
// Explorer tends to keep connection open, even after the
// tab gets closed: http://bugs.jquery.com/ticket/5280
this.unloadRef = utils.unloadAdd(function() {
debug('unload cleanup');
self._cleanup(true);
});
try {
this.xhr.open(method, url, true);
if (this.timeout && 'timeout' in this.xhr) {
this.xhr.timeout = this.timeout;
this.xhr.ontimeout = function() {
debug('xhr timeout');
self.emit('finish', 0, '');
self._cleanup(false);
};
}
} catch (e) {
debug('exception', e);
// IE raises an exception on wrong port.
this.emit('finish', 0, '');
this._cleanup(false);
return;
}
if ((!opts || !opts.noCredentials) && AbstractXHRObject.supportsCORS) {
debug('withCredentials');
// Mozilla docs says https://developer.mozilla.org/en/XMLHttpRequest :
// "This never affects same-site requests."
this.xhr.withCredentials = true;
}
if (opts && opts.headers) {
for (var key in opts.headers) {
this.xhr.setRequestHeader(key, opts.headers[key]);
}
}
this.xhr.onreadystatechange = function() {
if (self.xhr) {
var x = self.xhr;
var text, status;
debug('readyState', x.readyState);
switch (x.readyState) {
case 3:
// IE doesn't like peeking into responseText or status
// on Microsoft.XMLHTTP and readystate=3
try {
status = x.status;
text = x.responseText;
} catch (e) {
// intentionally empty
}
debug('status', status);
// IE returns 1223 for 204: http://bugs.jquery.com/ticket/1450
if (status === 1223) {
status = 204;
}
// IE does return readystate == 3 for 404 answers.
if (status === 200 && text && text.length > 0) {
debug('chunk');
self.emit('chunk', status, text);
}
break;
case 4:
status = x.status;
debug('status', status);
// IE returns 1223 for 204: http://bugs.jquery.com/ticket/1450
if (status === 1223) {
status = 204;
}
// IE returns this for a bad port
// http://msdn.microsoft.com/en-us/library/windows/desktop/aa383770(v=vs.85).aspx
if (status === 12005 || status === 12029) {
status = 0;
}
debug('finish', status, x.responseText);
self.emit('finish', status, x.responseText);
self._cleanup(false);
break;
}
}
};
try {
self.xhr.send(payload);
} catch (e) {
self.emit('finish', 0, '');
self._cleanup(false);
}
};
AbstractXHRObject.prototype._cleanup = function(abort) {
debug('cleanup');
if (!this.xhr) {
return;
}
this.removeAllListeners();
utils.unloadDel(this.unloadRef);
// IE needs this field to be a function
this.xhr.onreadystatechange = function() {};
if (this.xhr.ontimeout) {
this.xhr.ontimeout = null;
}
if (abort) {
try {
this.xhr.abort();
} catch (x) {
// intentionally empty
}
}
this.unloadRef = this.xhr = null;
};
AbstractXHRObject.prototype.close = function() {
debug('close');
this._cleanup(true);
};
AbstractXHRObject.enabled = !!XHR;
// override XMLHttpRequest for IE6/7
// obfuscate to avoid firewalls
var axo = ['Active'].concat('Object').join('X');
if (!AbstractXHRObject.enabled && (axo in global)) {
debug('overriding xmlhttprequest');
XHR = function() {
try {
return new global[axo]('Microsoft.XMLHTTP');
} catch (e) {
return null;
}
};
AbstractXHRObject.enabled = !!new XHR();
}
var cors = false;
try {
cors = 'withCredentials' in new XHR();
} catch (ignored) {
// intentionally empty
}
AbstractXHRObject.supportsCORS = cors;
module.exports = AbstractXHRObject;