post regenerations: regenerate posts asynchronously.

Regenerate posts asynchronously using a delayed job.

Regenerating a post can be slow because it involves downloading the
original file, regenerating the thumbnails, and redistributing the new
thumbnails back to the image servers. It's better to run this in the
background, especially if a user is trying to regenerate posts in bulk.

The downside is there's no notification to the user when the regeneration
is complete. You have to check the modactions log to see when it's finished.

app/controllers/post_regenerations_controller.rb

@@ -1,9 +1,10 @@
 class PostRegenerationsController < ApplicationController
-  respond_to :xml, :json, :js
+  respond_to :xml, :json, :html
 
   def create
     @post = authorize Post.find(params[:post_id]), :regenerate?
-    @post.regenerate!(params[:category], CurrentUser.user)
+    @post.regenerate_later!(params[:category], CurrentUser.user)
+    flash[:notice] = "Post regeneration scheduled, press Ctrl+F5 in a few seconds to refresh the image"
 
     respond_with(@post)
   end

app/jobs/regenerate_post_job.rb

@@ -0,0 +1,8 @@
+class RegeneratePostJob < ApplicationJob
+  queue_as :default
+  queue_with_priority 20
+
+  def perform(post:, category:, user:)
+    post.regenerate!(category, user)
+  end
+end

app/models/post.rb

@@ -1326,6 +1326,10 @@ class Post < ApplicationRecord
   end
 
   concerning :RegenerationMethods do
+    def regenerate_later!(category, user)
+      RegeneratePostJob.perform_later(post: self, category: category, user: user)
+    end
+
     def regenerate!(category, user)
       if category == "iqdb"
         update_iqdb_async

app/views/post_regenerations/create.js.erb

@@ -1 +0,0 @@
-Danbooru.notice("Post regenerated");

app/views/posts/partials/show/_options.html.erb

@@ -88,6 +88,6 @@
     <% end %>
 
     <% if policy(post).regenerate? %>
-      <li id="post-option-regenerate-preview"><%= link_to "Regenerate image", post_regenerations_path(post_id: post.id, category: "resizes"), remote: true, method: :post, "data-confirm": "This will regenerate the posts's thumbnail images. Are you sure?" %></li>
+      <li id="post-option-regenerate-preview"><%= link_to "Regenerate image", post_regenerations_path(post_id: post.id, category: "resizes"), method: :post, "data-confirm": "This will regenerate the posts's thumbnail images. Are you sure?" %></li>
     <% end %>
 </ul>

test/functional/post_regenerations_controller_test.rb

@@ -4,21 +4,63 @@ class PostRegenerationsControllerTest < ActionDispatch::IntegrationTest
   context "The post regenerations controller" do
     setup do
       @mod = create(:moderator_user, name: "yukari", created_at: 1.month.ago)
-      as(@mod) do
-        @post = create(:post, source: "https://google.com", tag_string: "touhou")
-      end
+      @upload = assert_successful_upload("test/files/test.jpg", user: @mod)
+      @post = @upload.post
     end
 
     context "create action" do
       should "render" do
         post_auth post_regenerations_path, @mod, params: { post_id: @post.id, category: "iqdb" }
-        assert_response :success
+
+        assert_redirected_to @post
+        assert_enqueued_jobs(1, only: RegeneratePostJob)
       end
 
       should "not allow non-mods to regenerate posts" do
         post_auth post_regenerations_path, create(:user), params: { post_id: @post.id, category: "iqdb" }
         assert_response 403
       end
+
+      context "for an IQDB regeneration" do
+        should "regenerate IQDB" do
+          mock_iqdb_service!
+          Post.iqdb_sqs_service.expects(:send_message).with("update\n#{@post.id}\n#{@post.preview_file_url}")
+
+          post_auth post_regenerations_path, @mod, params: { post_id: @post.id, category: "iqdb" }
+          perform_enqueued_jobs
+        end
+
+        should "log a mod action" do
+          post_auth post_regenerations_path, @mod, params: { post_id: @post.id, category: "iqdb" }
+          perform_enqueued_jobs
+
+          assert_equal(@mod, ModAction.last.creator)
+          assert_equal("post_regenerate_iqdb", ModAction.last.category)
+          assert_equal("@#{@mod.name} regenerated IQDB for post ##{@post.id}", ModAction.last.description)
+        end
+      end
+
+      context "for an image sample regeneration" do
+        should "regenerate missing thumbnails" do
+          @preview_file_size = @post.file(:preview).size
+          @post.storage_manager.delete_file(@post.id, @post.md5, @post.file_ext, :preview)
+          assert_raise(Errno::ENOENT) { @post.file(:preview) }
+
+          post_auth post_regenerations_path, @mod, params: { post_id: @post.id }
+          perform_enqueued_jobs
+
+          assert_equal(@preview_file_size, @post.file(:preview).size)
+        end
+
+        should "log a mod action" do
+          post_auth post_regenerations_path, @mod, params: { post_id: @post.id }
+          perform_enqueued_jobs
+
+          assert_equal(@mod, ModAction.last.creator)
+          assert_equal("post_regenerate", ModAction.last.category)
+          assert_equal("@#{@mod.name} regenerated image samples for post ##{@post.id}", ModAction.last.description)
+        end
+      end
     end
   end
 end