Allow ugoira to be uploaded directly from the zip URL.

This refactors things such that

* Fetching the ugoira frame data happens at the end of rewrite, not
  rewrite_html_pages. This way uploading zip URLs should work.
* The source data is cached in an instance variable in case it
  was indeed fetched during rewrite_html_pages. This way it doesn't get
  fetched a second time.

app/controllers/uploads_controller.rb

@@ -13,7 +13,7 @@ class UploadsController < ApplicationController
         "User-Agent" => "#{Danbooru.config.safe_app_name}/#{Danbooru.config.version}"
       }
       Downloads::RewriteStrategies::Base.strategies.each do |strategy|
-        @normalized_url, headers = strategy.new.rewrite(@normalized_url, headers)
+        @normalized_url, headers = strategy.new(@normalized_url).rewrite(@normalized_url, headers)
       end
 
       @post = Post.find_by_source(@normalized_url)

app/logical/downloads/file.rb

@@ -29,7 +29,7 @@ module Downloads
 
     def before_download(url, headers, datums)
       RewriteStrategies::Base.strategies.each do |strategy|
-        url, headers, datums = strategy.new.rewrite(url, headers, datums)
+        url, headers, datums = strategy.new(url).rewrite(url, headers, datums)
       end
 
       return [url, headers, datums]

app/logical/downloads/rewrite_strategies/base.rb

@@ -1,6 +1,10 @@
 module Downloads
   module RewriteStrategies
     class Base
+      def initialize(url = nil)
+        @url = url
+      end
+
       def self.strategies
         [Pixiv, NicoSeiga, Twitpic, DeviantArt, Tumblr, Moebooru]
       end

app/logical/downloads/rewrite_strategies/pixiv.rb

@@ -1,15 +1,26 @@
 module Downloads
   module RewriteStrategies
     class Pixiv < Base
+      attr_accessor :url, :source
+
+      def initialize(url)
+        @url  = url
+      end
+
       def rewrite(url, headers, data = {})
         if url =~ /https?:\/\/(?:\w+\.)?pixiv\.net/
           url, headers = rewrite_headers(url, headers)
           url, headers = rewrite_cdn(url, headers)
-          url, headers, data = rewrite_html_pages(url, headers, data)
+          url, headers = rewrite_html_pages(url, headers)
           url, headers = rewrite_thumbnails(url, headers)
           url, headers = rewrite_old_small_manga_pages(url, headers)
         end
 
+        data[:ugoira_frame_data] = source.ugoira_frame_data
+        data[:ugoira_width] = source.ugoira_width
+        data[:ugoira_height] = source.ugoira_height
+        data[:ugoira_content_type] = source.ugoira_content_type
+
         return [url, headers, data]
       end
 
@@ -27,17 +38,11 @@ module Downloads
       #   http://www.pixiv.net/member_illust.php?mode=manga_big&illust_id=18557054&page=1
       # Plus this:
       #   i2.pixiv.net/img-inf/img/2014/09/25/00/57/24/46170939_64x64.jpg
-      def rewrite_html_pages(url, headers, data)
+      def rewrite_html_pages(url, headers)
         if url =~ /illust_id=\d+/i || url =~ %r!pixiv\.net/img-inf/img/!i
-          source = ::Sources::Strategies::Pixiv.new(url)
-          source.get
-          data[:ugoira_frame_data] = source.ugoira_frame_data
-          data[:ugoira_width] = source.ugoira_width
-          data[:ugoira_height] = source.ugoira_height
-          data[:ugoira_content_type] = source.ugoira_content_type
-          return [source.file_url, headers, data]
+          return [source.file_url, headers]
         else
-          return [url, headers, data]
+          return [url, headers]
         end
       end
 
@@ -45,8 +50,7 @@ module Downloads
       #   http://i2.pixiv.net/img04/img/syounen_no_uta/46170939_m.jpg
       #   http://i1.pixiv.net/c/600x600/img-master/img/2014/09/24/23/25/08/46168376_p0_master1200.jpg
       def rewrite_thumbnails(url, headers)
-        source = ::Sources::Strategies::Pixiv.new(url)
-        url    = source.rewrite_thumbnails(url)
+        url = source.rewrite_thumbnails(url)
         return [url, headers]
       end
 
@@ -77,6 +81,16 @@ module Downloads
 
         return [url, headers]
       end
+
+      # Cache the source data so it gets fetched at most once.
+      def source
+        @source ||= begin
+          source = ::Sources::Strategies::Pixiv.new(url)
+          source.get
+
+          source
+        end
+      end
     end
   end
 end