sources: fix 4chan URL parsing.

Add support for is2.4chan.org image URLs and various old URL formats.

app/logical/source/url/four_chan.rb

@@ -17,14 +17,30 @@ class Source::URL::FourChan < Source::URL
     case [subdomain, domain, *path_segments]
 
     # https://boards.4channel.org/vt/thread/37293562#p37294005
-    in _, ("4channel.org" | "4chan.org"), board, "thread", /\A[0-9]+\z/ => thread_id
+    # http://boards.4chan.org/a/res/41938201
+    # http://zip.4chan.org/jp/res/3598845.html
+    in _, ("4channel.org" | "4chan.org"), board, ("thread" | "res"), /\A([0-9]+)(?:\.html)?\z/
       @board = board
-      @thread_id = thread_id.to_i
+      @thread_id = $1.to_i
       @post_id = fragment.to_s[/^p([0-9]+)$/, 1]&.to_i
 
     # https://i.4cdn.org/vt/1668729957824814.webm
     # https://i.4cdn.org/vt/1668729957824814s.jpg
-    in "i", "4cdn.org", board, /\A([0-9]+)(s?)\./
+    # https://is2.4chan.org/vg/1663135782567622.jpg
+    # http://is.4chan.org/vp/1483914199051.jpg
+    in ("i" | "is" | "is2"), _, board, /\A([0-9]+)(s?)\./
+      @board = board
+      @image_id = $1.to_i
+      @image_type = $2 == "s" ? :preview : :original
+      @full_image_url = url.to_s if @image_type == :original
+
+    # http://images.4chan.org/vg/src/1378607754334.jpg
+    # http://orz.4chan.org/e/src/1202811803217.png
+    # http://zip.4chan.org/a/src/1201922408724.jpg
+    # http://cgi.4chan.org/r/src/1210870653551.jpg
+    # http://cgi.4chan.org/f/src/0931.swf
+    # http://img.4chan.org/b/src/1226194386317.jpg
+    in _, "4chan.org", board, "src", /\A([0-9]+)(s?)\./
       @board = board
       @image_id = $1.to_i
       @image_type = $2 == "s" ? :preview : :original
@@ -36,7 +52,7 @@ class Source::URL::FourChan < Source::URL
   end
 
   def image_url?
-    host == "i.4cdn.org"
+    image_id.present?
   end
 
   def page_url

test/unit/sources/four_chan_test.rb

@@ -69,5 +69,21 @@ module Sources
         )
       end
     end
+
+    should "Parse 4chan URLs correctly" do
+      assert(Source::URL.image_url?("https://i.4cdn.org/vt/1668729957824814.webm"))
+      assert(Source::URL.image_url?("https://i.4cdn.org/vt/1668729957824814s.jpg"))
+      assert(Source::URL.image_url?("https://is2.4chan.org/vg/1663135782567622.jpg"))
+      assert(Source::URL.image_url?("http://is.4chan.org/vp/1483914199051.jpg"))
+      assert(Source::URL.image_url?("http://images.4chan.org/vg/src/1378607754334.jpg"))
+      assert(Source::URL.image_url?("http://orz.4chan.org/e/src/1202811803217.png"))
+      assert(Source::URL.image_url?("http://zip.4chan.org/a/src/1201922408724.jpg"))
+      assert(Source::URL.image_url?("http://cgi.4chan.org/r/src/1210870653551.jpg"))
+      assert(Source::URL.image_url?("http://img.4chan.org/b/src/1226194386317.jpg"))
+
+      assert(Source::URL.page_url?("https://boards.4channel.org/vt/thread/37293562#p37294005"))
+      assert(Source::URL.page_url?("http://boards.4chan.org/a/res/41938201"))
+      assert(Source::URL.page_url?("http://zip.4chan.org/jp/res/3598845.html"))
+    end
   end
 end