Check for save after update Rails 4

Question

An update method for one of my controllers looks like this:

def update
  @node = Node.find(params[:id])
  @video = @node.media
  @node.update(node_params)
  @video.update(title: @node.name, description: @node.description)
end

I need a callback to make sure that the @node and @video updated. What's the best way to do this?

Answer 1

You can test if the update succeeds...

  if @node.update(node_params)
    # handle success
    if @video.update(title: @node.name, description: @node.description)
      # etc...
    end
  else
    # handle fail
  end

In an ajax request, you can put the condition in the view:

<% if @node.errors.any? %>
  alert('<%= j(@node.errors.full_messages.join("\n")) %>');
<% else %>
  alert('Success')
<% end %>

Answer 2

Based on what you said, I think this is what you might want

def update
  @node = Node.find(params[:id])
  @video = @node.media
  @node_saved = true
  @video_saved = true
  begin
      @node.update_attirbutes!(node_params)
  rescue ActiveRecord::RecordInvalid
      @node_saved = false
  end

  begin
      @video.update_attributes!(title: @node.name, description: @node.description)
  rescue ActiveRecord::RecordInvalid
      @video_saved = false
  end

  render "mypage"
end

Inside your update.js.erb

...
if (<%= @node_saved %> === false) {
   // trigger flash message
};

if (<%= @video_saved %> === false) {
   // trigger flash message
};

I may still be misunderstanding what you want, but this or @Swards answer should answer your question.

Answer 3

Rails' .save and .update return true/false (boolean) depending on whether the action was successful.

The standard way of utilizing that in your flow is as follows:

def update
  @node = Node.find params[:id]

  respond_to do |format|
     if @node.update(node_params)
        format.js #-> invokes /views/nodes/update.js.erb
        format.json { render json: @node.to_json }
        format.html
     else
        format.js #-> invokes /views/nodes/update.js.erb
        format.json
        format.html
     end
  end
end

You shouldn't be using the @video.update using the exact same data as @node - you can do that in the model. You'll be best using associations etc, which I can explain if required.

#app/models/node.rb
class Node < ActiveRecord::Base
   belongs_to :media #?
   before_save :set_media, on: :update

   private

   def set_media
     self.media.name = self.name
     self.media.description = self.description
   end
end

---

Ajax

My front-end UI developer has some jQuery that I need a callback for

Since I don't know the spec for this, I cannot give you any specific code.

What I can tell you is that if you're using ajax, you have to make sure you understand the difference between server-side & client-side code.

I don't want to insult your intelligence but I'll explain it for posterity's sake...

Frontend ajax will look like this:

#app/assets/javascripts/application.js
$(document).on("click", ".element", function(){
   $.ajax({
      url: "...",
      data: ....,
      success: function(data) { },
      error: function(response) {}
   });
});

... since this is client side code, you can only deal with data returned from the server. A common misunderstanding is many people thinking they'll somehow be able to use Ruby code/methods in this. No.

You can only send back pre-packaged data to this, so if you wanted your data to be condition, you'd do something like this:

def update
   @node = Node.find params[:id]
   @returned = "yes" if @node.update(node_params)
   render [x], layout: !request.xhr?
end 

This will allow you to send back conditional data, with which you'll be able to use the front-end JS to manipulate:

$.ajax({
 ...
 success: function(data) {
    ... do something with data
 }

--

If you wanted to use server side code, you'll be better using the inbuilt format.js functionality:

def update
   @node = Node.find params[:id]
   respond_to do |format|
      format.js #-> app/views/nodes/update.js.erb
   end
end

This does allow you to use Ruby code, as the JS is rendered server-side, and passed to the browser. I'm not sure as to the specifics, but I know you can do the following with it:

#app/views/nodes/update.js.erb
<% if @node.something %>
   $("js")....
<% else %>
   ...
<% end %>