How to call method after render?

Question

I need to do request on remote service after rendering the page

My controller:

after_filter :remote_action, only: :update

def update
  @res = MyService.do_action foo, bar
  return render json: @res[:json], status: @res[:status] unless @res[:success]
end

def remote_action
  # There is remote http request
end

I need to call remote_action method after rendering the page

Answer 1

after_filter is run after the template has been converted into html, but before that html is sent as a response to the client. So, if you're doing something slow like making a remote http request, then that will slow your response down, as it needs to wait for that remote request to finish: in other words, the remote request will block your response.

To avoid blocking, you could fork off a different thread: have a look at

https://github.com/tra/spawnling

Using this, you would just change your code to

def remote_action
  Spawnling.new do
    # There is remote http request
  end
end

The remote call will still be triggered before the response is sent back, but because it's been forked off into a new thread, the response won't wait for the remote request to come back, it will just happen straight away.

You could also look at https://github.com/collectiveidea/delayed_job, which puts jobs into a database table, where a seperate process will pull them out and execute them.