Chrome extension webRequest.onBeforeRequest

Question

I am trying to create an extension to analyse requests made on the chrome browser but I can't put it work. The alert never fires.

manifest.json

{
  "name": "Test",
  "description": "Test",
  "version": "1.0",
  "manifest_version": 2,
  "permissions": ["background", "tabs", "webRequest", "webRequestBlocking", "*://*/*"],    
  "background": {
    "scripts": ["background.js"],
    "persistent": true
  }  
}

background.js

var callback = function(details) {
    alert("hello");
};
var filter = { "*://*/*" };
var opt_extraInfoSpec = [];

chrome.webRequest.onBeforeRequest.addListener(
        callback, filter, opt_extraInfoSpec);

Why is it my alert not firing?

Answer 1

Your filter is the wrong format - it's not a valid object at all. Addtionally it needs to contain at least the 'url' property. If you wan't all URL's, use this:

var filter = {urls: ["<all_urls>"]};

Check out this for exact details on the format for the filter: https://developer.chrome.com/extensions/webRequest#type-RequestFilter