firefox - Firefox 拡張機能で http 応答を変更する方法

Question

nsIStreamListener リスナーを作成して、応答をリッスンし、nsitraceablechannel-intercept-http-traffic のチュートリアルに従って応答テキストを取得することができました。しかし、ブラウザーに送信される応答を変更することはできません。チェーンに戻ると、firebug には反映されますが、ブラウザには反映されません。

私が推測しているのは、チェーンでリッスンするのではなく、デフォルトのリスナーを置き換える必要があるということです。これを行う方法を説明するドキュメントはどこにもありません。

誰でもこれについての洞察を得ることができます.これは主に教育目的のためです.

前もって感謝します

編集：今のところ、私はこれを行うことができる小さな解決策にたどり着きました

var old;

function TracingListener() {}

TracingListener.prototype = {
    originalListener: null,
    receivedData: null, //will be an array for incoming data.

//For the listener this is step 1.
onStartRequest: function (request, context) {
    this.receivedData = []; //initialize the array

    //Pass on the onStartRequest call to the next listener in the chain -- VERY         IMPORTANT
    //old.onStartRequest(request, context); 
},

//This is step 2. This gets called every time additional data is available
onDataAvailable: function (request, context, inputStream, offset, count) {
    var binaryInputStream = CCIN("@mozilla.org/binaryinputstream;1",
        "nsIBinaryInputStream");
    binaryInputStream.setInputStream(inputStream);

    var storageStream = CCIN("@mozilla.org/storagestream;1",
        "nsIStorageStream");
    //8192 is the segment size in bytes, count is the maximum size of the stream in     bytes
    storageStream.init(8192, count, null);

    var binaryOutputStream = CCIN("@mozilla.org/binaryoutputstream;1",
        "nsIBinaryOutputStream");
    binaryOutputStream.setOutputStream(storageStream.getOutputStream(0));

    // Copy received data as they come.
    var data = binaryInputStream.readBytes(count);

    this.receivedData.push(data);

    binaryOutputStream.writeBytes(data, count);



    //Pass it on down the chain
    //old.onDataAvailable(request, context,storageStream.newInputStream(0), offset, count); 
},
onStopRequest: function (request, context, statusCode) {
    try {
        //QueryInterface into HttpChannel to access originalURI and requestMethod properties
        request.QueryInterface(Ci.nsIHttpChannel);


        //Combine the response into a single string
        var responseSource = this.receivedData.join('');


        //edit data as needed
        responseSource = "test";
        console.log(responseSource);

    } catch (e) {
        //standard function to dump a formatted version of the error to console
        dumpError(e);
    }

    var stream = Cc["@mozilla.org/io/string-input-stream;1"]
        .createInstance(Ci.nsIStringInputStream);
    stream.setData(responseSource, -1);

    //Pass it to the original listener
    //old.originalListener=null;
    old.onStartRequest(channel, context);
    old.onDataAvailable(channel, context, stream, 0, stream.available());
    old.onStopRequest(channel, context, statusCode);
},
QueryInterface: function (aIID) {
    if (aIID.equals(Ci.nsIStreamListener) ||
        aIID.equals(Ci.nsISupports)) {
        return this;
    }
    throw components.results.NS_NOINTERFACE;
},
readPostTextFromRequest: function (request, context) {
    try {
        var is = request.QueryInterface(Ci.nsIUploadChannel).uploadStream;
        if (is) {
            var ss = is.QueryInterface(Ci.nsISeekableStream);
            var prevOffset;
            if (ss) {
                prevOffset = ss.tell();
                ss.seek(Ci.nsISeekableStream.NS_SEEK_SET, 0);
            }

            // Read data from the stream..
            var charset = "UTF-8";
            var text = this.readFromStream(is, charset, true);

            if (ss && prevOffset == 0)
                ss.seek(Ci.nsISeekableStream.NS_SEEK_SET, 0);

            return text;
        } else {
            dump("Failed to Query Interface for upload stream.\n");
        }
    } catch (exc) {
        dumpError(exc);
    }

    return null;
},
readFromStream: function (stream, charset, noClose) {

    var sis = CCSV("@mozilla.org/binaryinputstream;1",
        "nsIBinaryInputStream");
    sis.setInputStream(stream);

    var segments = [];
    for (var count = stream.available(); count; count = stream.available())
        segments.push(sis.readBytes(count));

    if (!noClose)
        sis.close();

   var text = segments.join("");
    return text;
}

}

httpRequestObserver = {

observe: function (request, aTopic, aData) {
    if (typeof Cc == "undefined") {
        var Cc = components.classes;
    }
    if (typeof Ci == "undefined") {
        var Ci = components.interfaces;
    }
    if (aTopic == "http-on-examine-response") {
        request.QueryInterface(Ci.nsIHttpChannel);

        console.log(request.statusCode);

        var newListener = new TracingListener();
        request.QueryInterface(Ci.nsITraceableChannel);

        channel = request;
        //newListener.originalListener 
        //add new listener as default and save old one 
        old = request.setNewListener(newListener);
        old.originalListener = null;

        var threadManager = Cc["@mozilla.org/thread-manager;1"]
            .getService(Ci.nsIThreadManager);
        threadManager.currentThread.dispatch(newListener,     Ci.nsIEventTarget.DISPATCH_NORMAL);


    }
},

QueryInterface: function (aIID) {
    if (typeof Cc == "undefined") {
        var Cc = components.classes;
    }
    if (typeof Ci == "undefined") {
        var Ci = components.interfaces;
    }
    if (aIID.equals(Ci.nsIObserver) ||
        aIID.equals(Ci.nsISupports)) {
        return this;
    }

    throw components.results.NS_NOINTERFACE;

},
};

var observerService = Cc["@mozilla.org/observer-service;1"]
.getService(Ci.nsIObserverService);

observerService.addObserver(httpRequestObserver,
"http-on-examine-response", false);