Issue 1372 - Work around a bug in Chrome 38 where 'object' requests have the wrong type

chrome/ext/background.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 270 matching lines @@
   chrome.webRequest.onBeforeRequest.addListener(function(details)
   {
     try
     {
       // the high-level code isn't interested in requests that aren't related
       // to a tab and since those can only be handled in Chrome, we ignore
       // them here instead of in the browser independent high-level code.
       if (details.tabId == -1)
         return;
 
-      var isMainFrame = details.type == "main_frame" || (
+      var requestType = details.type;
+      var isMainFrame = requestType == "main_frame" || (
+
         // assume that the first request belongs to the top frame. Chrome
         // may give the top frame the type "object" instead of "main_frame".
         // https://code.google.com/p/chromium/issues/detail?id=281711
         details.frameId == 0 && !(details.tabId in framesOfTabs)
       );
 
       var frames = null;
       if (!isMainFrame)
         frames = framesOfTabs[details.tabId];
       if (!frames)
         frames = framesOfTabs[details.tabId] = {__proto__: null};
 
       var frame = null;
       if (!isMainFrame)
       {
         // we are looking for the frame that contains the element that
         // is about to load, however if a frame is loading the surrounding
         // frame is indicated by parentFrameId instead of frameId
         var frameId;
-        if (details.type == "sub_frame")
+        if (requestType == "sub_frame")
           frameId = details.parentFrameId;
         else
           frameId = details.frameId;
 
         frame = frames[frameId] || frames[Object.keys(frames)[0]];
 
-        if (frame && !ext.webRequest.onBeforeRequest._dispatch(details.url, details.type, new Page({id: details.tabId}), frame))
-          return {cancel: true};
+        if (frame)
+        {
+          // Chrome 38 mistakenly reports requests of type 'object'
+          // (e.g. requests initiated by Flash) with the type 'other'.
+          // https://code.google.com/p/chromium/issues/detail?id=410382
+          if (requestType == "other" && / Chrome\/38\b/.test(navigator.userAgent))

[Sebastian Noack, 2014/09/25 15:00:53]

Just in case you wonder why I didn't used info.platformVersion and
Services.vc.compare here, it is because I want to avoid a dependency on
adblockplus.js. In fact adblockplus.js already depends on the abstraction layer.
And introducing circular dependencies just makes things painful and error-prone.
Also since we are only checking for the major number, it's more simple that way.

[Wladimir Palant, 2014/09/25 16:18:16]

I wonder whether we should really do this for Chrome 38 only - as opposed to
Chrome 38 and above. Well, there is always hope that this will simply be
fixed...

[Sebastian Noack, 2014/09/25 16:24:06]

In case this isn't fixed in Chrome 39, this workaround won't do any good anyway.
Note that in Chrome 39 Canary build almost everything is reported with type
"others".

+            requestType = "object";
+
+          if (!ext.webRequest.onBeforeRequest._dispatch(details.url, requestType, new Page({id: details.tabId}), frame))
+            return {cancel: true};
+        }
       }
 
       if (isMainFrame || details.type == "sub_frame")
         frames[details.frameId] = {url: details.url, parent: frame};
     }
     catch (e)
     {
       // recent versions of Chrome cancel the request when an error occurs in
       // the onBeforeRequest listener. However in our case it is preferred, to
       // let potentially some ads through, rather than blocking legit requests.
@@ skipping 29 matching lines @@
     };
 
     return ext.onMessage._dispatch(message, sender, sendResponse);
   });
 
 
   /* Storage */
 
   ext.storage = localStorage;
 })();