#1866: Tumblr thumbnail rewriting

app/logical/downloads/strategies/base.rb

@@ -2,12 +2,26 @@ module Downloads
   module Strategies
     class Base
       def self.strategies
-        [Pixiv, Twitpic, DeviantArt]
+        [Pixiv, Twitpic, DeviantArt, Tumblr]
       end
 
       def rewrite(url, headers)
         return [url, headers]
       end
+
+    protected
+      def http_exists?(url, headers)
+        exists = false
+        uri = URI.parse(url)
+        Net::HTTP.start(uri.host, uri.port) do |http|
+          http.request_head(uri.request_uri, headers) do |res|
+            if res.is_a?(Net::HTTPSuccess)
+              exists = true
+            end
+          end
+        end
+        exists
+      end
     end
   end
 end

app/logical/downloads/strategies/pixiv.rb

@@ -47,28 +47,13 @@ module Downloads
           match = $1
           repl = match.sub(/_p/, "_big_p")
           big_url = url.sub(match, repl)
-          if http_exists?(big_url)
+          if http_exists?(big_url, headers)
             url = big_url
           end
         end
 
         return [url, headers]
       end
-
-      def http_exists?(url)
-        # example: http://img01.pixiv.net/img/as-special/15649262_big_p2.jpg
-        exists = false
-        uri = URI.parse(url)
-        Net::HTTP.start(uri.host, uri.port) do |http|
-          headers = {"Referer" => "http://www.pixiv.net", "User-Agent" => "#{Danbooru.config.app_name}/#{Danbooru.config.version}"}
-          http.request_head(uri.request_uri, headers) do |res|
-            if res.is_a?(Net::HTTPSuccess)
-              exists = true
-            end
-          end
-        end
-        exists
-      end
     end
   end
 end

app/logical/downloads/strategies/tumblr.rb

@@ -0,0 +1,27 @@
+module Downloads
+  module Strategies
+    class Tumblr < Base
+      def rewrite(url, headers)
+        if url =~ %r{^http?://(?:(?:\d+\.)\w+\.)?tumblr\.com}
+          url, headers = rewrite_thumbnails(url, headers)
+        end
+
+        return [url, headers]
+      end
+
+    protected
+      def rewrite_thumbnails(url, headers)
+        if url =~ %r{^http?://.+\.tumblr\.com/(?:\w+/)?(?:tumblr_)?(\w+_)(250|400|500)\..+$}
+          match = $1
+          size = $2
+          big_url = url.sub(match + size, match + "1280")
+          if http_exists?(big_url, headers)
+            url = big_url
+          end
+        end
+
+        return [url, headers]
+      end
+    end
+  end
+end