refactor

app/logical/downloads/rewrite_strategies/base.rb

@@ -0,0 +1,27 @@
+module Downloads
+  module RewriteStrategies
+    class Base
+      def self.strategies
+        [Pixiv, NicoSeiga, Twitpic, DeviantArt, Tumblr, Moebooru]
+      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