uploads: refactor to simplify ugoira-handling and replacements:

* Make it so replacing a post doesn't generate a dummy upload as a side effect.
* Make it so you can't replace a post with itself (the post should be regenerated instead).
* Refactor uploads and replacements to save the ugoira frame data when
  the MediaAsset is created, not when the post is created. This way it's
  possible to view the ugoira before the post is created.
* Make `download_file!` in the Pixiv source strategy return a MediaFile
  with the ugoira frame data already attached to it, instead of returning it
  in the `data` field then passing it around separately in the `context`
  field of the upload.

app/logical/upload_service/preprocessor.rb

@@ -71,7 +71,7 @@ class UploadService
       begin
         upload.update(status: "preprocessing")
 
-        file = Utils.get_file_for_upload(upload, file: params[:file]&.tempfile)
+        file = Utils.get_file_for_upload(upload.source_url, upload.referer_url, params[:file]&.tempfile)
         Utils.process_file(upload, file, original_post_id: original_post_id)
 
         upload.rating = params[:rating]

app/logical/upload_service/replacer.rb

@@ -61,69 +61,44 @@ class UploadService
       undoer.process!
     end
 
-    def source_strategy(upload)
-      Sources::Strategies.find(upload.source, upload.referer_url)
-    end
-
-    def find_replacement_url(repl, upload)
-      if repl.replacement_file.present?
-        return "file://#{repl.replacement_file.original_filename}"
+    def replacement_url
+      if replacement.replacement_file.present?
+        "file://#{replacement.replacement_file.original_filename}"
+      else
+        Sources::Strategies.find(replacement.replacement_url).canonical_url
       end
-
-      if upload.source.blank?
-        raise "No source found in upload for replacement"
-      end
-
-      if source_strategy(upload).canonical_url.present?
-        return source_strategy(upload).canonical_url
-      end
-
-      upload.source
     end
 
     def process!
-      preprocessor = Preprocessor.new(
-        rating: post.rating,
-        tag_string: replacement.tags,
-        source: replacement.replacement_url,
-        file: replacement.replacement_file,
-        replaced_post: post,
-        original_post_id: post.id
-      )
-      upload = preprocessor.start!
-      raise Error, upload.status if upload.is_errored?
-      upload = preprocessor.finish!(upload)
-      raise Error, upload.status if upload.is_errored?
-      md5_changed = upload.md5 != post.md5
+      media_file = Utils::get_file_for_upload(replacement.replacement_url, nil, replacement.replacement_file&.tempfile)
 
-      replacement.replacement_url = find_replacement_url(replacement, upload)
-
-      if md5_changed
-        post.queue_delete_files(PostReplacement::DELETION_GRACE_PERIOD)
+      if media_file.md5 == post.md5
+        raise Error, "Can't replace a post with itself; regenerate the post instead"
+      elsif Post.exists?(md5: media_file.md5)
+        raise Error, "Duplicate: post with md5 #{media_file.md5} already exists"
       end
 
-      replacement.file_ext = upload.file_ext
-      replacement.file_size = upload.file_size
-      replacement.image_height = upload.image_height
-      replacement.image_width = upload.image_width
-      replacement.md5 = upload.md5
+      media_asset = MediaAsset.upload!(media_file)
+      post.queue_delete_files(PostReplacement::DELETION_GRACE_PERIOD)
 
-      post.md5 = upload.md5
-      post.file_ext = upload.file_ext
-      post.image_width = upload.image_width
-      post.image_height = upload.image_height
-      post.file_size = upload.file_size
+      replacement.replacement_url = replacement_url
+      replacement.file_ext = media_asset.file_ext
+      replacement.file_size = media_asset.file_size
+      replacement.image_height = media_asset.image_height
+      replacement.image_width = media_asset.image_width
+      replacement.md5 = media_asset.md5
+
+      post.md5 = media_asset.md5
+      post.file_ext = media_asset.file_ext
+      post.image_width = media_asset.image_width
+      post.image_height = media_asset.image_height
+      post.file_size = media_asset.file_size
       post.source = replacement.final_source.presence || replacement.replacement_url
-      post.tag_string = upload.tag_string
+      post.tag_string = replacement.tags
 
       rescale_notes(post)
-      update_ugoira_frame_data(post, upload)
 
-      if md5_changed
-        CurrentUser.scoped(User.system) { Comment.create!(post: post, creator: User.system, updater: User.system, body: comment_replacement_message(post, replacement), do_not_bump_post: true, creator_ip_addr: "127.0.0.1") }
-      else
-        purge_cached_urls(post)
-      end
+      CurrentUser.scoped(User.system) { Comment.create!(post: post, creator: User.system, updater: User.system, body: comment_replacement_message(post, replacement), do_not_bump_post: true, creator_ip_addr: "127.0.0.1") }
 
       replacement.save!
       post.save!
@@ -131,18 +106,6 @@ class UploadService
       post.update_iqdb
     end
 
-    def purge_cached_urls(post)
-      urls = [
-        post.preview_file_url,
-        post.large_file_url,
-        post.file_url,
-        post.tagged_large_file_url,
-        post.tagged_file_url
-      ]
-
-      CloudflareService.new.purge_cache(urls)
-    end
-
     def rescale_notes(post)
       x_scale = post.image_width.to_f  / post.image_width_was.to_f
       y_scale = post.image_height.to_f / post.image_height_was.to_f
@@ -151,19 +114,5 @@ class UploadService
         note.rescale!(x_scale, y_scale)
       end
     end
-
-    def update_ugoira_frame_data(post, upload)
-      post.pixiv_ugoira_frame_data.destroy if post.pixiv_ugoira_frame_data.present?
-
-      unless post.is_ugoira?
-        return
-      end
-
-      PixivUgoiraFrameData.create(
-        post_id: post.id,
-        data: upload.context["ugoira"]["frame_data"],
-        content_type: upload.context["ugoira"]["content_type"]
-      )
-    end
   end
 end

app/logical/upload_service/utils.rb

@@ -7,9 +7,9 @@ class UploadService
     end
 
     def process_file(upload, file, original_post_id: nil)
-      upload.file = file
-      media_file = upload.media_file
+      media_file = MediaFile.open(file)
 
+      upload.file = media_file
       upload.file_ext = media_file.file_ext.to_s
       upload.file_size = media_file.file_size
       upload.md5 = media_file.md5
@@ -28,25 +28,14 @@ class UploadService
       tags.join(" ")
     end
 
-    def get_file_for_upload(upload, file: nil)
-      return file if file.present?
-      raise "No file or source URL provided" if upload.source_url.blank?
+    def get_file_for_upload(source_url, referer_url, file)
+      return MediaFile.open(file) if file.present?
+      raise "No file or source URL provided" if source_url.blank?
 
-      strategy = Sources::Strategies.find(upload.source_url, upload.referer_url)
+      strategy = Sources::Strategies.find(source_url, referer_url)
       raise NotImplementedError, "No login credentials configured for #{strategy.site_name}." unless strategy.class.enabled?
 
-      file = strategy.download_file!
-
-      if strategy.data[:ugoira_frame_data].present?
-        upload.context = {
-          "ugoira" => {
-            "frame_data" => strategy.data[:ugoira_frame_data],
-            "content_type" => "image/jpeg"
-          }
-        }
-      end
-
-      file
+      strategy.download_file!
     end
   end
 end