Question

I’m working with Ruby and I need to send a constant update status message to the user while a long-running task is being performed in the controller.

The method inserts some rows on the database. What I want is to show the user a message like this:

Upload in progress, X number of files inserted.

Currently I’m using a LoadMask jQuery plugin but it only shows a simple message, and I dont know how to send the number of rows inserted with out interrupting the process.

Answer 1

You should consider moving this long running process to a background task, so you can immediately give feedback to the user. Once the background job has been submitted, depending on your background processing engine, you will be able to check the status of jobs. It’s probably simple to keep track of the status yourself (depending on your task). Use either Redis or just in your database (create a separate table for this). Once the job has been submitted, you need to return the id of the job which you can use to poll for updates.

Create a new controller (or action) that you can use jQuery + Ajax and poll for changes. giving it a job_id (which your previous action returned)

Please also look at:
Faye: http://faye.jcoglan.com/, http://railscasts.com/episodes/260-messaging-with-faye
Goliath: http://postrank-labs.github.com/goliath/

http://railscasts.com/episodes/229-polling-for-changes

Delayed Job, Resque, etc.

Oh, If you are just looking for a simple file upload progress indicator, see this Rails, upload progress bar

You can try the streaming technique as well, lots of info on that here:
Ruby on Rails 3: Streaming data through Rails to client