'use strict';
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// Few cool transports do work only for same-origin. In order to make
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// them work cross-domain we shall use iframe, served from the
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// remote domain. New browsers have capabilities to communicate with
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// cross domain iframe using postMessage(). In IE it was implemented
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// from IE 8+, but of course, IE got some details wrong:
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// http://msdn.microsoft.com/en-us/library/cc197015(v=VS.85).aspx
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// http://stevesouders.com/misc/test-postmessage.php
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var inherits = require('inherits')
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, EventEmitter = require('events').EventEmitter
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, version = require('../version')
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, urlUtils = require('../utils/url')
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, iframeUtils = require('../utils/iframe')
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, eventUtils = require('../utils/event')
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, random = require('../utils/random')
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;
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var debug = function() {};
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if (process.env.NODE_ENV !== 'production') {
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debug = require('debug')('sockjs-client:transport:iframe');
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}
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function IframeTransport(transport, transUrl, baseUrl) {
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if (!IframeTransport.enabled()) {
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throw new Error('Transport created when disabled');
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}
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EventEmitter.call(this);
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var self = this;
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this.origin = urlUtils.getOrigin(baseUrl);
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this.baseUrl = baseUrl;
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this.transUrl = transUrl;
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this.transport = transport;
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this.windowId = random.string(8);
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var iframeUrl = urlUtils.addPath(baseUrl, '/iframe.html') + '#' + this.windowId;
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debug(transport, transUrl, iframeUrl);
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this.iframeObj = iframeUtils.createIframe(iframeUrl, function(r) {
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debug('err callback');
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self.emit('close', 1006, 'Unable to load an iframe (' + r + ')');
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self.close();
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});
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this.onmessageCallback = this._message.bind(this);
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eventUtils.attachEvent('message', this.onmessageCallback);
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}
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inherits(IframeTransport, EventEmitter);
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IframeTransport.prototype.close = function() {
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debug('close');
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this.removeAllListeners();
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if (this.iframeObj) {
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eventUtils.detachEvent('message', this.onmessageCallback);
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try {
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// When the iframe is not loaded, IE raises an exception
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// on 'contentWindow'.
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this.postMessage('c');
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} catch (x) {
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// intentionally empty
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}
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this.iframeObj.cleanup();
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this.iframeObj = null;
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this.onmessageCallback = this.iframeObj = null;
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}
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};
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IframeTransport.prototype._message = function(e) {
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debug('message', e.data);
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if (!urlUtils.isOriginEqual(e.origin, this.origin)) {
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debug('not same origin', e.origin, this.origin);
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return;
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}
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var iframeMessage;
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try {
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iframeMessage = JSON.parse(e.data);
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} catch (ignored) {
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debug('bad json', e.data);
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return;
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}
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if (iframeMessage.windowId !== this.windowId) {
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debug('mismatched window id', iframeMessage.windowId, this.windowId);
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return;
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}
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switch (iframeMessage.type) {
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case 's':
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this.iframeObj.loaded();
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// window global dependency
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this.postMessage('s', JSON.stringify([
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version
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, this.transport
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, this.transUrl
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, this.baseUrl
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]));
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break;
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case 't':
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this.emit('message', iframeMessage.data);
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break;
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case 'c':
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var cdata;
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try {
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cdata = JSON.parse(iframeMessage.data);
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} catch (ignored) {
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debug('bad json', iframeMessage.data);
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return;
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}
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this.emit('close', cdata[0], cdata[1]);
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this.close();
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break;
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}
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};
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IframeTransport.prototype.postMessage = function(type, data) {
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debug('postMessage', type, data);
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this.iframeObj.post(JSON.stringify({
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windowId: this.windowId
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, type: type
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, data: data || ''
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}), this.origin);
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};
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IframeTransport.prototype.send = function(message) {
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debug('send', message);
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this.postMessage('m', message);
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};
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IframeTransport.enabled = function() {
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return iframeUtils.iframeEnabled;
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};
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IframeTransport.transportName = 'iframe';
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IframeTransport.roundTrips = 2;
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module.exports = IframeTransport;
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