http request/response observer template module

httpreqrespobserver.js

/* Any copyright is dedicated to the Public Domain.
 * http://creativecommons.org/publicdomain/zero/1.0/ */
"use strict";

const EXPORTED_SYMBOLS = ['HttpRequestObserver'];

const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
const module = Cu.import;
const error =  Cu.reportError;

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

function HttpRequestObserver() {
	this._init();
}
HttpRequestObserver.prototype = {
	QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver, Ci.nsISupportsWeakReference, Ci.nsIWeakReference]),
	QueryReferent: function(iid) this.QueryInterface(iid),
	GetWeakReference: function() this,

	_init: function _init() {
		Services.obs.addObserver(this, 'xpcom-shutdown', true);
		this._registerHttpObservers();
	},

	_uninit: function _uninit() {
		this._unregisterHttpObservers();
		Services.obs.removeObserver(this, 'xpcom-shutdown');
	},
	_registerHttpObservers: function _registerHttpObservers() {
		Services.obs.addObserver(this, 'http-on-modify-request', true);
		Services.obs.addObserver(this, 'http-on-examine-response', true);
		Services.obs.addObserver(this, 'http-on-examine-cached-response', true);
	},
	_unregisterHttpObservers: function _unregisterHttpObservers() {
		Services.obs.removeObserver(this, 'http-on-modify-request');
		Services.obs.removeObserver(this, 'http-on-examine-response');
		Services.obs.removeObserver(this, 'http-on-examine-cached-response');
	},
	observe: function observe(subject, topic, data) {
		switch(topic) {
		case 'xpcom-shutdown':
			this._uninit();
			break;
		case 'http-on-modify-request':
			this.observeRequest(subject, topic, data);
			break;
		case 'http-on-examine-response':
		case 'http-on-examine-cached-response':
			this.observeResponse(subject, topic, data);
			break;
		}
	},
	observeRequest: function observeRequest(channel, topic, data) {
		if (!(channel instanceof Ci.nsIHttpChannel)) {
			return;
		}
		error("Request: " + channel.requestMethod + ": " + channel.URI.spec);
	},
	observeResponse: function observeResponse(channel, topic, data) {
		if (!(channel instanceof Ci.nsIHttpChannel)) {
			return;
		}
		error("Response: " + channel.responseStatus + ": " + channel.URI.spec);
	}
};

HttpRequestObserver = new HttpRequestObserver();