Question

我已阅读NsIContentPolicy并已搜索整个Stackoverflow以获取实施NsIContentPolicy的正确教程，但都是徒劳的。我知道Adblock使用NsIContentPolicy作为主要武器。逆向工程Adblock没有帮助我理解如何实现NsIContentPolicy。是否有使用NsIContentPolicy进行学习的简单插件，或者有关NsIContentPolicy的任何优秀教程？

Answer 1

我不知道任何好的教程，但我可以给你一些最小的示例代码：

Cu.import("resource://gre/modules/XPCOMUtils.jsm");
Cu.import("resource://gre/modules/Services.jsm");

let policy =
{
  classDescription: "Test content policy",
  classID: Components.ID("{12345678-1234-1234-1234-123456789abc}"),
  contractID: "@adblockplus.org/test-policy;1",
  xpcom_categories: ["content-policy"],

  init: function()
  {
    let registrar = Components.manager.QueryInterface(Ci.nsIComponentRegistrar);
    registrar.registerFactory(this.classID, this.classDescription, this.contractID, this);

    let catMan = Cc["@mozilla.org/categorymanager;1"].getService(Ci.nsICategoryManager);
    for each (let category in this.xpcom_categories)
      catMan.addCategoryEntry(category, this.contractID, this.contractID, false, true);

    onShutdown.add((function()
    {
      for each (let category in this.xpcom_categories)
        catMan.deleteCategoryEntry(category, this.contractID, false);

      // This needs to run asynchronously, see bug 753687
      Services.tm.currentThread.dispatch(function()
      {
        registrar.unregisterFactory(this.classID, this);
      }.bind(this), Ci.nsIEventTarget.DISPATCH_NORMAL);
    }).bind(this));
  },

  // nsIContentPolicy interface implementation
  shouldLoad: function(contentType, contentLocation, requestOrigin, node, mimeTypeGuess, extra)
  {
    dump("shouldLoad: " + contentType + " " +
                          (contentLocation ? contentLocation.spec : "null") + " " +
                          (requestOrigin ? requestOrigin.spec : "null") + " " +
                          node + " " +
                          mimeTypeGuess + "\n");
    return Ci.nsIContentPolicy.ACCEPT;
  },

  shouldProcess: function(contentType, contentLocation, requestOrigin, node, mimeTypeGuess, extra)
  {
    dump("shouldProcess: " + contentType + " " +
                            (contentLocation ? contentLocation.spec : "null") + " " +
                            (requestOrigin ? requestOrigin.spec : "null") + " " +
                            node + " " +
                            mimeTypeGuess + "\n");
    return Ci.nsIContentPolicy.ACCEPT;
  },

  // nsIFactory interface implementation
  createInstance: function(outer, iid)
  {
    if (outer)
      throw Cr.NS_ERROR_NO_AGGREGATION;
    return this.QueryInterface(iid);
  },

  // nsISupports interface implementation
  QueryInterface: XPCOMUtils.generateQI([Ci.nsIContentPolicy, Ci.nsIFactory])
};

policy.init();

这来自我用来查看内容策略实现问题的最小内容策略实现 - 除了将所有内容策略调用转储到控制台（window.dump documentation）之外，它不会执行任何操作。显然，在实际实现中，字段classDescription，classID和contractID应该更改为正确的内容。 onShutdown属于我正在使用的私有框架：这个扩展是无重启的，这就是为什么它需要“手动”注册组件，并且如果在浏览器会话期间关闭它也将运行此代码以删除它。 / p>

您还可以下载完整的扩展程序：testpolicy.xpi。

firefox插件的nsIContentPolicy示例？

1 个答案: