#1866: Support twitpic source rewriting

* html work page -> full image
* thumbnail -> full image

app/logical/downloads/file.rb

@@ -69,7 +69,7 @@ module Downloads
                 if limit == 0 then
                   raise Error.new("Too many redirects")
                 end
-                source = res["location"]
+                @source = res["location"]
                 limit -= 1
 
               else

app/logical/downloads/strategies/base.rb

@@ -2,7 +2,7 @@ module Downloads
   module Strategies
     class Base
       def self.strategies
-        [Pixiv]
+        [Pixiv, Twitpic]
       end
 
       def rewrite(url, headers)

app/logical/downloads/strategies/twitpic.rb

@@ -0,0 +1,36 @@
+module Downloads
+  module Strategies
+    class Twitpic < Base
+      def rewrite(url, headers)
+        if url =~ %r{http://twitpic\.com} || url =~ %r{^http://d3j5vwomefv46c\.cloudfront\.net}
+          url, headers = rewrite_html_pages(url, headers)
+          url, headers = rewrite_thumbnails(url, headers)
+        end
+
+        return [url, headers]
+      end
+
+    protected
+      def rewrite_html_pages(url, headers)
+        # example: http://twitpic.com/cpprns
+
+        if url =~ %r{http://twitpic\.com/([a-z0-9]+)$}
+          id = $1
+          url = "http://twitpic.com/show/full/#{id}"
+          return [url, headers]
+        else
+          return [url, headers]
+        end
+      end
+
+      def rewrite_thumbnails(url, headers)
+        if url =~ %r{^http://d3j5vwomefv46c\.cloudfront\.net/photos/thumb/(\d+\..+)$}
+          match = $1
+          url.sub!("/thumb/" + match, "/large/" + match)
+        end
+
+        return [url, headers]
+      end
+    end
+  end
+end