Ajax check for database change using route

问题

I'm using Paperclip with Delayed::Job to process photos in the background. When processing is done, the model should set photo.attachment_is_processing to false.

I need to check for this change on the client side. I understand I can do this by querying a route using Ajax, however:

How should the route look like?

Possible clues from schema.rb:

  create_table "forem_posts", force: :cascade do |t|
    t.integer  "topic_id"
    t.text     "text"
    t.integer  "user_id"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.integer  "reply_to_id"
    t.string   "state",       default: "pending_review"
    t.boolean  "notified",    default: false
  end

  create_table "photos", force: :cascade do |t|
    t.integer  "post_id"
    t.datetime "created_at"
    t.datetime "updated_at"
    t.string   "attachment_file_name"
    t.string   "attachment_content_type"
    t.integer  "attachment_file_size"
    t.datetime "attachment_updated_at"
    t.boolean  "attachment_is_animated"
    t.boolean  "attachment_is_processing", default: false
  end

Possible clues from rake routes:

            forum_topic_posts POST   /:forum_id/topics/:topic_id/posts(.:format)              forem/posts#create
         new_forum_topic_post GET    /:forum_id/topics/:topic_id/posts/new(.:format)          forem/posts#new
        edit_forum_topic_post GET    /:forum_id/topics/:topic_id/posts/:id/edit(.:format)     forem/posts#edit
             forum_topic_post GET    /:forum_id/topics/:topic_id/posts/:id(.:format)          forem/posts#show
                              PATCH  /:forum_id/topics/:topic_id/posts/:id(.:format)          forem/posts#update
                              PUT    /:forum_id/topics/:topic_id/posts/:id(.:format)          forem/posts#update

When that is done, how do I actually tie photo.attachment_is_processing to the returning of true or false from that route?

回答1:

You probably want something like this:

routes.rb

get '/check_photo_processing/:id', to: 'photos#check_photo_processing', as: :check_photo_processing

photos_controller.rb

def check_photo_processing
  @photo_status = Photo.find(params[:photo_id]).attachment_is_processing
  respond_to do |wants|
    wants.js
  end
end

Then in views/photos/check_photo_processing.js

alert("<%= @photo_status %>");
// do what you gotta do with the status here

Finally, to tie it all together you need a function to create the AJAX request. If you're using Coffeescript in your app:

check_photo_status: ( photo_id ) ->
    $.ajax(
        type: 'GET'
        url: "/check_photo_status/#{ photo_id }.js"
    )

Then call it from a view somewhere

<script>
  check_photo_status(@photo.id);
  // or pass in the photo id somehow
</script>

Because there wasn't much sample code provided in the question, this is only a basic configuration for how to accomplish what you need. You'll probably have to tweak it a bit to get it working with your app.

来源：https://stackoverflow.com/questions/29329620/ajax-check-for-database-change-using-route

标签

ruby-on-rails

routes