Javascript 如何确定Firefox浏览器中的哪个选项卡将发出http请求

我目前正在尝试构建一个firefox扩展，它基于正则表达式为每个http请求确定一个代理。用于加载页面的代理应该记住来自该页面的任何新请求，即该页面所需的任何图像/脚本/css文件、任何传出链接或ajax请求。这也意味着每个打开的选项卡都需要记住代理。 这就是我遇到问题的地方：到目前为止，我试图通过插入一个唯一的id作为选项卡浏览器元素的属性来标记每个打开的选项卡，并在nsiContentPolicy的shoulLoad（）方法的实现中查找该id。我用于此目的的代码如下所示，它是从tabs/utils.js中的插件sdk的getTabForContentWindow方法中提取的

shouldLoad: function(contentType, contentLocation, requestOrigin, context, mimeTypeGuess, extra)
  {
      var tabId = null;

      if (!(context instanceof CI.nsIDOMWindow))
      {
        // If this is an element, get the corresponding document
        if (context instanceof CI.nsIDOMNode && context.ownerDocument)
          context = context.ownerDocument;

        // Now we should have a document, get its window
        if (context instanceof CI.nsIDOMDocument)
          context = context.defaultView;
        else
          context = null;
      }

      let browser;
      try {
        browser = context.QueryInterface(CI.nsIInterfaceRequestor)
                        .getInterface(CI.nsIWebNavigation)
                        .QueryInterface(CI.nsIDocShell)
                        .chromeEventHandler;
      } catch(e) {
        this.console.log(e);
      }

      let chromeWindow = browser.ownerDocument.defaultView;
      if ('gBrowser' in chromeWindow && chromeWindow.gBrowser &&
           'browsers' in chromeWindow.gBrowser) {

      let browsers = chromeWindow.gBrowser.browsers;
      let i = browsers.indexOf(browser);
      if (i !== -1)
        tabId = chromeWindow.gBrowser.tabs[i].getAttribute("PMsMark");
      }     
    return CI.nsIContentPolicy.ACCEPT;
  }

这适用于任何不改变所显示文档的加载，但一旦文档发生变化（即加载新页面），变量

browser

即为空

我已经研究了上所述的拦截页面加载的其他机制，但这些机制似乎不适合我想要实现的目标，因为据我所知，它们适用于HTTP请求，并且对于存在的请求，已经需要确定代理

因此，如果有人知道一种方法来在即将到来的负载变成请求之前捕获它们，同时，可以找出哪个选项卡负责这些负载，我很高兴他们能在回答中告诉我！提前谢谢

---

当然，这只是http/https。我不确定你是否还能在这一点上摆弄代理。哦，并不是每个

nsILoadContext

都有一个

associatedWindow

（或者

topWindow

），所以最好改进错误处理嘿@pmuench在这里查看更好的错误处理版本：哦，等等@namaier我现在很困惑，在哪些情况下loaddcontext没有关联的窗口？如果它加载在选项卡中，它总是有关联的窗口，对吗？如果它没有加载到选项卡中，那么它甚至不应该具有loadcontext权限？文档（在idl中）状态可能为空。这就是合同。其中，只有一个可能返回窗口，1个确实返回null（webapps.jsm），2个始终抛出（LoadContext、OfflineCacheUpdateParent，两个都是e10）。此外，附加组件可以根据合同自由实现接口并返回null（例如Lightning就是这样做的）。有时候我不应该这么匆忙。当在打开请求时使用http而不是http-on-modify-request时，它会起作用。如下面对Noitidart建议的评论所述，在修改请求事件时侦听http并不能解决问题，因为事件是在确定请求的代理后触发的。但是，在打开请求事件时侦听http是可行的。

Components.utils.import('resource://gre/modules/Services.jsm');
Services.obs.addObserver(httpObs, 'http-on-opening-request', false);
//Services.obs.removeObserver(httpObs, 'http-on-modify-request'); //uncomment this line, or run this line when you want to remove the observer

var httpObs = {
    observe: function (aSubject, aTopic, aData) {
        if (aTopic == 'http-on-opening-request') {
            /*start - do not edit here*/
            var oHttp = aSubject.QueryInterface(Components.interfaces.nsIHttpChannel); //i used nsIHttpChannel but i guess you can use nsIChannel, im not sure why though
            var interfaceRequestor = oHttp.notificationCallbacks.QueryInterface(Components.interfaces.nsIInterfaceRequestor);
            //var DOMWindow = interfaceRequestor.getInterface(Components.interfaces.nsIDOMWindow); //not to be done anymore because: https://developer.mozilla.org/en-US/docs/Updating_extensions_for_Firefox_3.5#Getting_a_load_context_from_a_request //instead do the loadContext stuff below
            var loadContext;
            try {
                loadContext = interfaceRequestor.getInterface(Components.interfaces.nsILoadContext);
            } catch (ex) {
                try {
                    loadContext = aSubject.loadGroup.notificationCallbacks.getInterface(Components.interfaces.nsILoadContext);
                    //in ff26 aSubject.loadGroup.notificationCallbacks was null for me, i couldnt find a situation where it wasnt null, but whenever this was null, and i knew a loadContext is supposed to be there, i found that "interfaceRequestor.getInterface(Components.interfaces.nsILoadContext);" worked fine, so im thinking in ff26 it doesnt use aSubject.loadGroup.notificationCallbacks anymore, but im not sure
                } catch (ex2) {
                    loadContext = null;
                    //this is a problem i dont know why it would get here
                }
            }
            /*end do not edit here*/
            /*start - do all your edits below here*/
            var url = oHttp.URI.spec; //can get url without needing loadContext
            if (loadContext) {
                var contentWindow = loadContext.associatedWindow; //this is the HTML window of the page that just loaded
                //aDOMWindow this is the firefox window holding the tab
                var aDOMWindow = contentWindow.top.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIWebNavigation).QueryInterface(Ci.nsIDocShellTreeItem).rootTreeItem.QueryInterface(Ci.nsIInterfaceRequestor).getInterface(Ci.nsIDOMWindow);
                var gBrowser = aDOMWindow.gBrowser; //this is the gBrowser object of the firefox window this tab is in
                var aTab = gBrowser._getTabForContentWindow(contentWindow.top); //this is the clickable tab xul element, the one found in the tab strip of the firefox window, aTab.linkedBrowser is same as browser var above //can stylize tab like aTab.style.backgroundColor = 'blue'; //can stylize the tab like aTab.style.fontColor = 'red';
                var browser = aTab.linkedBrowser; //this is the browser within the tab //this is what the example in the previous section gives
                //end getting other useful stuff
            } else {
                Components.utils.reportError('EXCEPTION: Load Context Not Found!!');
                //this is likely no big deal as the channel proably has no associated window, ie: the channel was loading some resource. but if its an ajax call you may end up here
            }
        }
    }
};