检索和修改 XMLHttpRequest 的内容

问题描述

我正在为 Firefox、Safari、Chrome 开发一个浏览器插件，它将拦截页面上的数据，针对正则表达式运行它，然后如果匹配 - 重新格式化它.我使用以下方法处理页面加载:

I am working on a browser plugin for Firefox, Safari, Chrome that will intercept data on the page, run it against a regex and then if it matches - reformat it. I have this working on page load using:

var meth = {
  replaceInElement : function(element, find, replace) {
        // iterate over child nodes and replace
  },
  run : function(evt){
    // doc is the document that triggered "run" event
    if (!(evt.target.nodeName === "#document")) { return; }
    var doc = evt.target; // document that triggered "onload" event
    if (!(doc instanceof HTMLDocument)) { return; }
    if (!doc.location) { return; }

    // perform substitutions on the loaded document
    var find = /regex/gi

    meth.replaceInElement(doc.body, find, function(match) {
        var new_content;
        //do stuff
        return new_content;
    });

    //content.document.addEventListener('DOMNodeInserted', ezcall.node_inserted, false);
  }
}

window.addEventListener("load", meth.run, false);

这适用于静态页面，但对于使用 ajax 调用的任何内容，它都会失败.我找不到合适的侦听器或弄清楚如何拦截 XMLHttpRequest.

This is working for static pages, but for anything using ajax calls, it fails. I cannot find the right listener or figure out how to intercept the XMLHttpRequest.

我为 XMLHttpRequest 尝试了类似的事件侦听器，但没有成功.

I have tried similar event listeners for XMLHttpRequest with no luck.

XMLHttpRequest.addEventListener('load', meth.run, false);

我想拦截请求并修改内容.或者找到更新的目标，在ajax调用完成后扫描.

I would like to either intercept the request and modify the content. Or find the target that was updated and scan it after the ajax call is finished.

更新:

我会接受无法完成的回答，但我需要一些支持数据来说明为什么无法完成.

I will accept an answer that says it cannot be done, but I will need some supporting data as to why it cannot be done.

推荐答案

比较脏但是你可以覆盖XMLHttpRequest.prototype.open.这是一个演示页面.由于您正在编写扩展程序，因此您必须将此代码放在页面上下文中:

Rather dirty but you can overwrite XMLHttpRequest.prototype.open. Here is a Demo page. Since you're writing an extension, you must put this code in page context:

(function() {
    // save reference to the native method
    var oldOpen = XMLHttpRequest.prototype.open;
    // overwrite open with our own function
    XMLHttpRequest.prototype.open = function(method, url, async, user, pass) {
        // intercept readyState changes
        this.addEventListener("readystatechange", function() {
            // your code goes here...
            console.log("Interception :) " + this.readyState);
        }, false);
        // finally call the original open method
        oldOpen.call(this, method, url, async, user, pass);
    };
})();

在这之后你可以做任何我猜的事情.替换 instance.readystatechange，替换 instance.addEventListener，或者监听突变事件(虽然它们是 已弃用).

After this you can do anything I guess. Replace instance.readystatechange, replace instance.addEventListener, or listen to mutation events (although they are deprecated).

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