integrate ugoira converted into upload flow

app/logical/sources/strategies/pixiv.rb

@@ -57,6 +57,31 @@ module Sources
         return thumbnail_url
       end
 
+      def agent
+        @agent ||= begin
+          mech = Mechanize.new
+
+          phpsessid = Cache.get("pixiv-phpsessid")
+          if phpsessid
+            cookie = Mechanize::Cookie.new("PHPSESSID", phpsessid)
+            cookie.domain = ".pixiv.net"
+            cookie.path = "/"
+            mech.cookie_jar.add(cookie)
+          else
+            mech.get("http://www.pixiv.net") do |page|
+              page.form_with(:action => "/login.php") do |form|
+                form['pixiv_id'] = Danbooru.config.pixiv_login
+                form['pass'] = Danbooru.config.pixiv_password
+              end.click_button
+            end
+            phpsessid = mech.cookie_jar.cookies.select{|c| c.name == "PHPSESSID"}.first
+            Cache.put("pixiv-phpsessid", phpsessid.value, 1.month) if phpsessid
+          end
+
+          mech
+        end
+      end
+      
     protected
 
       # http://i1.pixiv.net/c/600x600/img-master/img/2014/10/02/13/51/23/46304396_p1_master1200.jpg