Issue 5184 - Support Firefox-specific webRequest types

lib/requestBlocker.js

Index: lib/requestBlocker.js
===================================================================
--- a/lib/requestBlocker.js
+++ b/lib/requestBlocker.js
@@ -24,19 +24,31 @@
 const {defaultMatcher} = require("matcher");
 const {FilterNotifier} = require("filterNotifier");
 const {Prefs} = require("prefs");
 const {checkWhitelisted, getKey} = require("whitelisting");
 const {stringifyURL, extractHostFromFrame, isThirdParty} = require("url");
 const {port} = require("messaging");
 const devtools = require("devtools");
 
-// Chrome can't distinguish between OBJECT_SUBREQUEST and OBJECT requests.
+// Chrome and Firefox (WebExtensions) can't distinguish between
+// OBJECT_SUBREQUEST and OBJECT requests.
 RegExpFilter.typeMap.OBJECT_SUBREQUEST = RegExpFilter.typeMap.OBJECT;
 
+let resourceTypes = new Map(
+  Object.keys(RegExpFilter.typeMap).map(type => [type.toLowerCase(), type])
+  .concat([
+    // Map unsupported resource types to types we support. Anything that isn't

[Sebastian Noack, 2017/05/19 17:47:41]

I wouldn't consider these resource types "unsupported", but rather translated
into a more abstract model.

For reference, this is the original mapping in the legacy Gecko extension (which
has more comprehensive comments for the mapped types):
https://hg.adblockplus.org/adblockplus/file/ce08e8e0aabf/lib/contentPolicy.js...

Also I'd wonder what you think about the approach, there, creating the Map from
a generator? I don't have a strong opinion. But if you think it's more readable
you might want to adopt it here.

[Manish Jethani, 2017/05/19 23:44:15]

OK, I've just copied that comment over and changed "Firefox" to "the browser".
Feels like an unnecessary use of a generator, but doesn't hurt and probably not
a bad idea to go for it for consistency. I've made the change.

[Sebastian Noack, 2017/05/20 06:42:37]

As I said, I don't have a strong opinion. So if you'd rather not use a generator
here that is fine too. Though I personally don't like chains of .map() and
.concat() either. And the generator syntax seems to be the approach with the
least boilerplate. But up to you.

[Manish Jethani, 2017/05/20 18:50:47]

Acknowledged.

+    // mapped here is implicitly mapped to "OTHER".
+    ["beacon", "PING"],
+    ["imageset", "IMAGE"],
+    ["sub_frame", "SUBDOCUMENT"]
+  ])
+);
+
 function onBeforeRequestAsync(page, url, type, docDomain,
                               thirdParty, sitekey,
                               specificOnly, filter)
 {
   if (filter)
     FilterNotifier.emit("filter.hitCount", filter, 0, 0, page);
 
   if (devtools)
@@ -58,23 +70,25 @@
   let docDomain = extractHostFromFrame(frame);
   let thirdParty = isThirdParty(url, docDomain);
   let sitekey = getKey(page, frame);
 
   let specificOnly = !!checkWhitelisted(
     page, frame, RegExpFilter.typeMap.GENERICBLOCK
   );
 
+  let mappedType = resourceTypes.get(type) || "OTHER";
+
   let filter = defaultMatcher.matchesAny(
-    urlString, RegExpFilter.typeMap[type],
+    urlString, RegExpFilter.typeMap[mappedType],
     docDomain, thirdParty, sitekey, specificOnly
   );
 
   setTimeout(onBeforeRequestAsync, 0, page, urlString,
-                                      type, docDomain,
+                                      mappedType, docDomain,
                                       thirdParty, sitekey,
                                       specificOnly, filter);
 
   return !(filter instanceof BlockingFilter);
 });
 
 port.on("filters.collapse", (message, sender) =>
 {