Autodelete phpsessid

fixes #2382

app/logical/sources/strategies/pixiv.rb

@@ -57,7 +57,15 @@ module Sources
       end
 
       def get
-        agent.get(URI.parse(normalized_url)) do |page|
+        page = agent.get(URI.parse(normalized_url))
+        
+        if page.search("body.not-logged-in").any?
+          # Session cache is invalid, clear it and log in normally.
+          Cache.delete("pixiv-phpsessid")
+          @agent = nil
+          page = agent.get(URI.parse(normalized_url))
+        end
+        
         @artist_name, @profile_url = get_profile_from_page(page)
         @pixiv_moniker = get_moniker_from_page(page)
         @zip_url, @ugoira_frame_data, @ugoira_content_type = get_zip_url_from_page(page)
@@ -71,7 +79,6 @@ module Sources
           @image_url = get_image_url_from_page(page, is_manga)
         end
       end
-      end
 
       def rewrite_thumbnails(thumbnail_url, is_manga=nil)
         thumbnail_url = rewrite_new_medium_images(thumbnail_url)