I try to implement a basic XHR listener as described in "Ashita" however when loading firefox using the extension I get this error every time I try to load a page that doesn’t allow anything to load: Error: uncaught exception: [Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIBinaryInputStream.readBytes]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: chrome://xhrlogger/content/overlay.js :: anonymous :: line 68" data: no]
My overlay.js:
if (typeof Cc == "undefined") {
var Cc = Components.classes;
}
if (typeof Ci == "undefined") {
var Ci = Components.interfaces;
}
if (typeof CCIN == "undefined") {
function CCIN (cName, ifaceName) {
return Cc [cName] .createInstance (Ci [ifaceName]);
}
}
if (typeof CCSV == "undefined") {
function CCSV (cName, ifaceName) {
if (Cc [cName])
// if fbs fails to load, the error can be _CC [cName] has no properties
return Cc [cName] .getService (Ci [ifaceName]);
else
dump ("CCSV fails for cName:" + cName);
};
}
var httpRequestObserver = {
observe: function (request, aTopic, aData) {
if (aTopic == "http-on-examine-response") {
var newListener = new TracingListener ();
request.QueryInterface (Ci.nsITraceableChannel);
newListener.originalListener = request.setNewListener (newListener);
}
},
QueryInterface: function (aIID) {
if (aIID.equals (Ci.nsIObserver) ||
aIID.equals (Ci.nsISupports)) {
return this;
}
throw Components.results.NS_NOINTERFACE;
},
};
function TracingListener () {
this.receivedData = []; // initialize the array
}
TracingListener.prototype =
{
originalListener: null,
receivedData: null, // will be an array for incoming data.
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
this.originalListener.onDataAvailable (request, context, inputStream, offset, count);
},
onStartRequest: function (request, context) {
this.originalListener.onStartRequest (request, context);
},
onStopRequest: function (request, context, statusCode) {
try
{
// QueryInterface into HttpChannel to access originalURI and requestMethod properties
request.QueryInterface (Ci.nsIHttpChannel);
var data = null;
if (request.requestMethod.toLowerCase () == "post")
{
var postText = this.readPostTextFromRequest (request, context);
if (postText)
data = ((String) (postText)). parseQuery ();
}
// Combine the response into a single string
var responseSource = this.receivedData.join ('');
// fix leading spaces bug
// (FM occasionally adds spaces to the beginning of their ajax responses ...
// which breaks the XML)
responseSource = responseSource.replace (/ ^ \ s + (\ S [\ s \ S] +) /, "$ 1");
// gets the date from the response headers on the request.
// For PirateQuesting this was preferred over the date on the user machine
var date = Date.parse (request.getResponseHeader ("Date"));
// Again a PQ specific function call, but left as an example.
// This just passes a string URL, the text of the response,
// the date, and the data in the POST request (if applicable)
/ * piratequesting.ProcessRawResponse (request.originalURI.spec,
responseSource,
date
data); * /
dump (date);
dump (data);
dump (responseSource);
}
catch (e)
{
// standard function to dump a formatted version of the error to console
dump (e);
}
this.originalListener.onStopRequest (request, context, statusCode);
},
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)
{
dump (exc);
}
return null;
},
QueryInterface: function (aIID) {
if (aIID.equals (Ci.nsIStreamListener) ||
aIID.equals (Ci.nsISupports)) {
return this;
}
throw Components.results.NS_NOINTERFACE;
},
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;
}
}
var observerService = Cc ["@ mozilla.org/observer-service;1"]
.getService (Ci.nsIObserverService);
observerService.addObserver (httpRequestObserver,
"http-on-examine-response", false);
dump ("WTFBBQ");
Any help would be most appreciated.