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June 9, 2014 16:33
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/* | |
* JBoss, Home of Professional Open Source | |
* Copyright 2013, Red Hat, Inc. and individual contributors | |
* by the @authors tag. See the copyright.txt in the distribution for a | |
* full listing of individual contributors. | |
* | |
* This is free software; you can redistribute it and/or modify it | |
* under the terms of the GNU Lesser General Public License as | |
* published by the Free Software Foundation; either version 2.1 of | |
* the License, or (at your option) any later version. | |
* | |
* This software is distributed in the hope that it will be useful, | |
* but WITHOUT ANY WARRANTY; without even the implied warranty of | |
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
* Lesser General Public License for more details. | |
* | |
* You should have received a copy of the GNU Lesser General Public | |
* License along with this software; if not, write to the Free | |
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA | |
* 02110-1301 USA, or see the FSF site: http://www.fsf.org. | |
*/ | |
window.Graphene = window.Graphene || {}; | |
/** | |
* The XMLHttpRequest injection providing ability to intercept requests. | |
*/ | |
window.Graphene.xhrInterception = (function() { | |
/** | |
* The backup of original XHR object after injection | |
*/ | |
var original; | |
/** | |
* Flags for different implementations of XHR | |
*/ | |
var isXHR = !!window.XMLHttpRequest; | |
var isActiveX = !!window.ActiveXObject; | |
/** | |
* The hash of arrays of functions (with method names to intercept like keys) | |
*/ | |
var interceptors = {}; | |
/** | |
* The prototype of injected XHR object. | |
* | |
* Delegates to intercepter chain. | |
*/ | |
var wrapperPrototype = { | |
abort : function() { | |
return invokeInterceptorChain(this, 'abort', arguments); | |
}, | |
open : function() { | |
return invokeInterceptorChain(this, 'open', arguments); | |
}, | |
getAllResponseHeaders : function() { | |
return invokeInterceptorChain(this, 'getAllResponseHeaders', arguments); | |
}, | |
getResponseHeader : function() { | |
return invokeInterceptorChain(this, 'getResponseHeader', arguments); | |
}, | |
send : function() { | |
return invokeInterceptorChain(this, 'send', arguments); | |
}, | |
setRequestHeader : function() { | |
return invokeInterceptorChain(this, 'setRequestHeader', arguments); | |
}, | |
onreadystatechange : undefined | |
}; | |
/** | |
* Injects XHR wrapper for Firefox/Chromium/WebKit and similar browsers | |
*/ | |
var replaceXHR = function() { | |
original = window.XMLHttpRequest; | |
window.XMLHttpRequest = createReplacement(); | |
}; | |
/** | |
* Reverts XHR wrapper for Firefox/Chromium/WebKit and similar browsers | |
*/ | |
var revertXHR = function() { | |
window.XMLHttpRequest = original; | |
original = undefined; | |
}; | |
/** | |
* Creates XHR wrapper for replacement of original XHR object | |
*/ | |
var createReplacement = function() { | |
var InterceptedXMLHttpRequest = function InterceptedXMLHttpRequest() { | |
this.xhr = invokeInterceptorChain(this, 'construct'); | |
this.readyState = this.xhr.readyState; | |
this.response = this.xhr.response; | |
this.responseType = this.xhr.responseType; | |
//do not read the response parameters until open/send functions are called: the ActiveXObjects do not like it | |
if (this.xhr.readyState == 4) { | |
this.responseText = this.xhr.responseText; | |
this.responseXML = this.xhr.responseXML; | |
this.status = this.xhr.status; | |
this.statusText = this.xhr.statusText; | |
} | |
this.xhr.onreadystatechange = callback(this); | |
}; | |
InterceptedXMLHttpRequest.prototype = wrapperPrototype; | |
return InterceptedXMLHttpRequest; | |
}; | |
/** | |
* onreadystatechange callback which is registered on true XHR instance. | |
* | |
* Delegates to intercepter chain. | |
*/ | |
var callback = function(wrapper) { | |
return function() { | |
//do not use 'this' since host objects behave differently | |
wrapper.readyState = wrapper.xhr.readyState; | |
if (wrapper.readyState == 4) { | |
wrapper.responseText = wrapper.xhr.responseText; | |
wrapper.responseXML = wrapper.xhr.responseXML; | |
wrapper.status = wrapper.xhr.status; | |
wrapper.statusText = wrapper.xhr.statusText; | |
} | |
invokeInterceptorChain(wrapper, 'onreadystatechange', [ wrapper ]); | |
}; | |
}; | |
/** | |
* Decides which injection is necessary for current browser | |
*/ | |
var replace = function() { | |
if (isXHR) { | |
replaceXHR(); | |
} | |
}; | |
/** | |
* Decides which injection is necessary for current browser | |
*/ | |
var revert = function() { | |
if (isXHR) { | |
revertXHR(); | |
} | |
}; | |
/** | |
* Registers intercepter in the chain of intercepters. | |
*/ | |
var registerInterceptor = function(methodName, interceptor) { | |
interceptors[methodName] = interceptors[methodName] || []; | |
interceptors[methodName].push(interceptor); | |
}; | |
/** | |
* Starts the execution of interceptor chain. | |
* | |
* The method calls or the interceptors in the chain and once all of them are fired, calls original implementation. | |
* | |
* @param wrapper | |
* XHR wrapper instance | |
* @param methodName | |
* the name of the method invoked | |
* @param arguments | |
* of the invocation | |
* @param i | |
* (optional) the number of interceptor to invoke (if there is no such interceptor, function delegates to real | |
* method) | |
*/ | |
var invokeInterceptorChain = function(wrapper, methodName, args, i) { | |
var i = i || 0; | |
if (interceptors[methodName] && interceptors[methodName].length > i) { | |
return invokeNextInterceptor(wrapper, methodName, args, i); | |
} else { | |
return invokeRealMethod(wrapper, methodName, args); | |
} | |
}; | |
/** | |
* Invokes next intercepter in the chain | |
*/ | |
var invokeNextInterceptor = function(wrapper, methodName, args, i) { | |
var context = { | |
xhrOriginal : wrapper.xhr, | |
xhrWrapper : wrapper, | |
proceed : function() { | |
return invokeInterceptorChain(wrapper, methodName, args, i + 1); | |
} | |
}; | |
var interceptor = interceptors[methodName][i]; | |
return interceptor.call(wrapper, context, args); | |
}; | |
/** | |
* Invokes original XHR implemention method. | |
* | |
* If onreadystatechange callback is processed, it is invoked on wrapper; otherwise method of the XHR instance is invoked. | |
*/ | |
var invokeRealMethod = function(wrapper, methodName, args) { | |
//proxy both types, the native and host, objects | |
var xhr = (methodName === 'onreadystatechange') ? wrapper : new XMLHttpRequestProxy(wrapper.xhr); | |
if (methodName === 'construct') { | |
return new original(); | |
} | |
if (xhr[methodName]) { | |
return xhr[methodName].apply(xhr, args); | |
} | |
}; | |
/** | |
* Proxy for native and ActiveXObject XMLHttpRequest instances. | |
* Simply expands the (arguments-) array into function calls since we do not have any | |
* 'splat' functions in JavaScript. | |
* Enables transparent invocation of <i>call</i> and <i>apply</i> functions on host objects. | |
* @param xhr original XHR instance. | |
**/ | |
var XMLHttpRequestProxy = function (xhr) { | |
this.xhr = xhr; | |
}; | |
XMLHttpRequestProxy.prototype.abort = function() { | |
return this.xhr.abort(); | |
}; | |
XMLHttpRequestProxy.prototype.open = function(method, url, async, user, password) { | |
return this.xhr.open(method, url, async, user, password); | |
}; | |
XMLHttpRequestProxy.prototype.send = function(data) { | |
return this.xhr.send(data); | |
}; | |
XMLHttpRequestProxy.prototype.getAllResponseHeaders = function() { | |
return this.xhr.getAllResponseHeaders(); | |
}; | |
XMLHttpRequestProxy.prototype.getResponseHeader = function(header) { | |
return this.xhr.getResponseHeader(header); | |
}; | |
XMLHttpRequestProxy.prototype.setRequestHeader = function(header, value) { | |
return this.xhr.setRequestHeader(header, value); | |
}; | |
/* PUBLIC METHODS */ | |
return { | |
/** | |
* Ensures the interceptor is installed properly | |
*/ | |
install : function() { | |
if (!original) { | |
replace(); | |
} | |
}, | |
/** | |
* Removes all registered interceptors. | |
*/ | |
uninstall : function() { | |
interceptors = {}; | |
if (original) { | |
revert(); | |
} | |
}, | |
onConstruct : function(interceptor) { | |
registerInterceptor('construct', interceptor); | |
}, | |
/** | |
* Registers intercepter for abort method. | |
* | |
* Interceptor is function with two params: context and args. | |
* | |
* Sample: function(context, args) { context.proceed(args); } | |
*/ | |
onAbort : function(interceptor) { | |
registerInterceptor('abort', interceptor); | |
}, | |
/** | |
* Registers intercepter for open method. | |
* | |
* Interceptor is function with two params: context and args. | |
* | |
* Sample: function(context, args) { context.proceed(args); } | |
*/ | |
onOpen : function(interceptor) { | |
registerInterceptor('open', interceptor); | |
}, | |
/** | |
* Registers intercepter for getAllResponseHeaders method. | |
* | |
* Interceptor is function with two params: context and args. | |
* | |
* Sample: function(context, args) { context.proceed(args); } | |
*/ | |
onGetAllResponseHeaders : function(interceptor) { | |
registerInterceptor('getAllResponseHeaders', interceptor); | |
}, | |
/** | |
* Registers intercepter for send method. | |
* | |
* Interceptor is function with two params: context and args. | |
* | |
* Sample: function(context, args) { context.proceed(args); } | |
*/ | |
onSend : function(interceptor) { | |
registerInterceptor('send', interceptor); | |
}, | |
/** | |
* Registers intercepter for setRequestHeader method. | |
* | |
* Interceptor is function with two params: context and args. | |
* | |
* Sample: function(context, args) { context.proceed(args); } | |
*/ | |
onSetRequestHeader : function(interceptor) { | |
registerInterceptor('setRequestHeader', interceptor); | |
}, | |
/** | |
* Registers intercepter for onreadystatechange callback method. | |
* | |
* Interceptor is function with two params: context and args. | |
* | |
* Sample: function(context, args) { context.proceed(args); } | |
*/ | |
onreadystatechange : function(interceptor) { | |
registerInterceptor('onreadystatechange', interceptor); | |
} | |
} | |
})(); |
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