Issue 5130 - Changes listener to register <all_urls> and filter non ws http requests

ext/background.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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 545 matching lines @@
             if (parentFrameId != -1)
               frames[details[i].frameId].parent = frames[parentFrameId];
           }
         }
       });
     });
   });
 
   chrome.webRequest.onBeforeRequest.addListener(details =>
   {
-    // Filter out requests from non web protocols since Chrome version
-    // 58 added support for webSocket connections to the webRequests API

[Jon Sonesen, 2017/04/20 19:19:58]

this comment should likely be improved. perhaps we can decide on that here

[Sebastian Noack, 2017/04/20 19:34:15]

"Filter out requests from non web protocols. Ideally, we'd explicitly specify
the protocols we are interested in (i.e. http://, https://, ws:// and wss://)
with the url patterns, given below, when adding this listener. But
unfortunately, Chrome <=57 doesn't support the WebSocket protocol and is causing
an error if it is given."

[Jon Sonesen, 2017/04/20 19:53:06]

Acknowledged. Thank you, I think that is good.

-    let blockURLs = new RegExp("https?|wss?");
-    let url = new URL(details.url);

[Sebastian Noack, 2017/04/20 19:34:15]

We are now creating two URL objects, one to validate the protocol here, and on
we pass to ext.webRequest.onBeforeRequest._dispatch(). Please reuse the URL
object which we create here below.

[Jon Sonesen, 2017/04/20 19:53:06]

Ah, sorry about that.

-    if (!blockURLs.exec(url.protocol))

[Sebastian Noack, 2017/04/20 19:34:15]

Since the regular expression doesn't make the code here much simpler, I'd rather
check for the 4 possible values explicitly (which is also faster):

  if (url.protocol == 'http:' || url.protocol == 'https:' ||
      url.protocol == 'ws:' || url.protocol == 'wss:')

[Sebastian Noack, 2017/04/20 19:36:22]

I accidentally inverted the logic, should be of course:

   if (url.protocol != 'http:' && url.protocol != 'https:' &&
       url.protocol != 'ws:' && url.protocol != 'wss:')

[Jon Sonesen, 2017/04/20 19:53:06]

Yeah, happy to use this instead.

-    {

[Sebastian Noack, 2017/04/20 19:34:15]

We generally omit the braces if there is only one line in the block.

[Jon Sonesen, 2017/04/20 19:53:06]

Done.

-      return {cancel: false};

[Sebastian Noack, 2017/04/20 19:34:15]

For consistency with the other bailout condition below, and to avoid creating an
unnecessary object, please omit the optional return value (which is equivalent
to returning {cancel: false}).

[Jon Sonesen, 2017/04/20 19:53:06]

Done.

-    }
     // The high-level code isn't interested in requests that aren't
     // related to a tab or requests loading a top-level document,
     // those should never be blocked.
     if (details.tabId == -1 || details.type == "main_frame")
+      return;
+
+    // Filter out requests from non web protocols. Ideally, we'd explicitly
+    // specify the protocols we are interested in (i.e. http://, https://,
+    // ws:// and wss://) with the url patterns, given below, when adding this
+    // listener. But unfortunately, Chrome <=57 doesn't support the WebSocket
+    // protocol and is causing an error if it is given.
+    let url = new URL(details.url);
+    if (url.protocol != "http:" && url.protocol != "https:" &&
+        url.protocol != "ws:" && url.protocol != "wss:")
       return;
 
     // We are looking for the frame that contains the element which
     // has triggered this request. For most requests (e.g. images) we
     // can just use the request's frame ID, but for subdocument requests
     // (e.g. iframes) we must instead use the request's parent frame ID.
     let {frameId, type} = details;
     if (type == "sub_frame")
     {
       frameId = details.parentFrameId;
       type = "SUBDOCUMENT";
     }
 
     let frame = ext.getFrame(details.tabId, frameId);
     if (frame)
     {
       let results = ext.webRequest.onBeforeRequest._dispatch(
-        new URL(details.url),
-        type.toUpperCase(),
-        new Page({id: details.tabId}),
-        frame
+        url, type.toUpperCase(), new Page({id: details.tabId}), frame
       );
 
       if (results.indexOf(false) != -1)
         return {cancel: true};
     }
   }, {urls: ["<all_urls>"]}, ["blocking"]);
 
 
   /* Message passing */
 
@@ skipping 123 matching lines @@
   ext.windows = {
     create(createData, callback)
     {
       chrome.windows.create(createData, createdWindow =>
       {
         afterTabLoaded(callback)(createdWindow.tabs[0]);
       });
     }
   };
 }());