/**
* xhr_proxy.js
* Listens to achieve page ajax request by hijacking native XMLHttpRequest
* @author binaryfire
*/
const READY_STATE_CHANGE = 'readystatechange';
the let gHandlerList = [], the function intercepts the request list processing @
gIsInited = false ; // been initialized
let T_RSC_HANDLERS = Symbol('readyStateChangeHandler');
let initProxy = function(){
if(gIsInited)return;
gIsInited = true;
// Here the first cache a native XMLHttpRequest class
let winXMLHttpRequest = window.XMLHttpRequest;
//用于替换原生XMLHttpRequest的类，继承自XMLHttpRequest
let ProxyXHR = class extends winXMLHttpRequest{
constructor(){
super(...arguments);
//readystatechange
//数组中第0个为页面中调用xhr.onreadystatechange的回调函数
//其他的为页面中调用addEventListener('readystatechange')时的回调函数
this[T_RSC_HANDLERS] = [null];
//调用原生XMLHttpRequest的addEventListener，添加对readystatechange事件的监听
super.addEventListener(READY_STATE_CHANGE,async ()=>{
if(this.readyState == 4 && gHandlerList.length){//只有4的时候会回调proxyHandler
try{
//调用注册的handler
await gHandlerList.map(proxyHandler => proxyHandler.call(this,this));
}
catch(e){
//TODO 这里可以替换为其他的错误处理逻辑
console.error(e);
}
}
//调用页面中注册的回调函数，保证页面中逻辑正常
this[T_RSC_HANDLERS].forEach(handler => handler && handler.apply(this,arguments));
});
}
/**
* 重写addEventListener函数，对readystatechange事件做特殊处理
*/
addEventListener(type,handler){
if(type == READY_STATE_CHANGE){
this[T_RSC_HANDLERS].push(handler);
}
else{
return super.addEventListener(...arguments);
}
}
/**
* 重写removeEventListener函数，对readystatechange事件做特殊处理
*/
removeEventListener(type,handler){
if(type == READY_STATE_CHANGE){
this[T_RSC_HANDLERS] = this[T_RSC_HANDLERS].filter(i => i!== handler);
}
else{
return super.removeEventListener(...arguments);
}
}
/**
* 重写onreadystatechange属性的setter
*/
set onreadystatechange(val){
this[T_RSC_HANDLERS][0] = val;
}
/**
* 重写onreadystatechange属性的getter
*/
get onreadystatechange(){
return this[T_RSC_HANDLERS][0] || null;
}
}
//覆盖原生的XMLHttpRequest
window.XMLHttpRequest = ProxyXHR;
}
/**
* 增加一个handler
* 当xhr.readyState == 4时，回调handler，handler中，可以通过xhr.responseText获取请求返回内容
* @param {function} handler function(xhr){}
*/
let addHandler = function(handler){
initProxy();
gHandlerList.push(handler);
}
/**
* 移除指定的handler
* @param {function} handler 调用addHandler时添加的handler
*/
let removeHandler = function(handler){
gHandlerList = gHandlerList.filter(h => h!== handler);
}
module.exports.addHandler = addHandler;
module.exports.removeHandler = removeHandler;
<webview id="foo" src="https://wx.qq.com/" preload="./preload.js" nodeintegration allowpopups disablewebsecurity style="min-width:640px; min-height:1000px"></webview>
/**
* preload.js
*/
const xhrProxy = require('./xhr_proxy.js');
const {ipcRenderer} = require('electron');
xhrProxy.addHandler(function(xhr){
let data = {};
//TODO 具体业务代码
console.log(xhr.responseText)
//通过ipcRenderer.sendToHost即可将xhr内容发送到BrowserWindow中
ipcRenderer.sendToHost('channel',data);
});