tumblr: rewrite samples to biggest available version.

app/logical/downloads/rewrite_strategies/tumblr.rb

@@ -1,44 +1,60 @@
 module Downloads
   module RewriteStrategies
+    DOMAIN = '(data|(\d+\.)?media)\.tumblr\.com'
+    MD5 = '(?<md5>[0-9a-f]{32})'
+    FILENAME = '(?<filename>(tumblr_(inline_)?)?[a-z0-9]+(_r[0-9]+)?)'
+    SIZES = '(250|400|500|500h|540|1280|raw)'
+    EXT = '(?<ext>\w+)'
+
     class Tumblr < Base
       def rewrite(url, headers, data = {})
-        if url =~ %r{^https?://.*tumblr\.com}
-          url, headers = rewrite_cdn(url, headers)
-          url, headers = rewrite_thumbnails(url, headers)
-        end
+        url = rewrite_cdn(url)
+        url = rewrite_samples(url, headers)
 
         return [url, headers, data]
       end
 
     protected
-      def rewrite_thumbnails(url, headers)
-        if url =~ %r{^https?://.+\.tumblr\.com/(?:\w+/)?(?:tumblr_)?(\w+_)(\d+)(\..+)$}
-          match = $1
-          given_size = $2
-          file_ext = $3
+      # Look for the biggest available version on data.tumblr.com. A bigger
+      # version may or may not exist.
+      #
+      # http://40.media.tumblr.com/d8c6d49785c0842ee31ff26c010b7445/tumblr_naypopLln51tkufhoo2_500h.png
+      # => http://data.tumblr.com/d8c6d49785c0842ee31ff26c010b7445/tumblr_naypopLln51tkufhoo2_raw.png
+      #
+      # https://40.media.tumblr.com/de018501416a465d898d24ad81d76358/tumblr_nfxt7voWDX1rsd4umo1_r23_1280.jpg
+      # => http://data.tumblr.com/de018501416a465d898d24ad81d76358/tumblr_nfxt7voWDX1rsd4umo1_r23_raw.jpg
+      #
+      # https://68.media.tumblr.com/ee02048f5578595badc95905e17154b4/tumblr_inline_ofbr4452601sk4jd9_250.gif
+      # => http://data.tumblr.com/ee02048f5578595badc95905e17154b4/tumblr_inline_ofbr4452601sk4jd9_500.gif
+      #
+      # https://25.media.tumblr.com/tumblr_m2dxb8aOJi1rop2v0o1_500.png
+      # => http://data.tumblr.com/tumblr_m2dxb8aOJi1rop2v0o1_1280.png
+      #
+      # http://data.tumblr.com/0DNBGJovY5j3smfeQs8nB53z_400.jpg
+      # => http://data.tumblr.com/0DNBGJovY5j3smfeQs8nB53z_500.jpg
+      #
+      # http://data.tumblr.com/tumblr_m24kbxqKAX1rszquso1_1280.jpg
+      # => http://data.tumblr.com/tumblr_m24kbxqKAX1rszquso1_1280.jpg
+      def rewrite_samples(url, headers)
+        if url =~ %r!\Ahttps?://#{DOMAIN}/(?<dir>#{MD5}/)?#{FILENAME}_#{SIZES}\.#{EXT}\z!i
+          sizes = ["raw", 1280, 540, 500, 400, 250]
+          candidates = sizes.map do |size|
+            "http://data.tumblr.com/#{$~[:dir]}#{$~[:filename]}_#{size}.#{$~[:ext]}"
+          end
 
-          big_1280_url = url.sub(match + given_size, match + "1280")
-          if file_ext == ".gif"
-            res = http_head_request(big_1280_url, headers)
-            # Sometimes the 1280 version of a gif is actually a static jpeg. We don't want that so we only use the 1280 version if it really is a gif.
-            if res.is_a?(Net::HTTPSuccess) && res["content-type"] == "image/gif"
-              return [big_1280_url, headers]
-            end
-          else
-            if http_exists?(big_1280_url, headers)
-              return [big_1280_url, headers]
-            end
+          url = candidates.find do |candidate|
+            http_exists?(candidate, headers)
           end
         end
 
-        return [url, headers]
+        url
       end
 
       # https://gs1.wac.edgecastcdn.net/8019B6/data.tumblr.com/tumblr_m2dxb8aOJi1rop2v0o1_500.png
       # => http://data.tumblr.com/tumblr_m2dxb8aOJi1rop2v0o1_500.png
-      def rewrite_cdn(url, headers)
+      def rewrite_cdn(url)
         url.sub!(%r!\Ahttps?://gs1\.wac\.edgecastcdn\.net/8019B6/data\.tumblr\.com!i, "http://data.tumblr.com")
-        return [url, headers]
+        url
       end
     end
   end