From: Matthieu Stone <matt.stone@...>
Date: 2007-04-01T04:43:45+09:00
Subject: Re: updating an RJS template _while_ executing a method

Here's one way

In your method doing the IO stuff, update a session variable with the
message that you want displayed; ie: 

  def my_io_process
    session[:message] = "Starting..."
    do something
    session[:message] = "Updated message"
    do something else.. etc
    session[:message] = nil
  end

  
Create another controller method that just returns the value of
session[:message].

  def update_message
    render :text => session[:message]; :layout => false
  end

So now, all you need is a periodic routine that updates a div on the page
with the session[:message] contents. You can either update the div directly
from this call, or like I do, use RJS to do other things on the page. This
polling is turned on & off by the javascript variable poll_message

<%= periodically_call_remote(
      :condition => "poll_message == true",
      :frequency => 2,
      :url       => { :action => 'update_message', :only_path => false }
    ) %>


You can turn poll_message on & off like this, just include this code in a
RJS update whenever you want to change turn the polling on & off.

  <script type="text/javascript">
  //<![CDATA[
    <% if @session[:message] && !@session[:message].blank? %>
      poll_message = true;
    <% else %>
      Poll_message = false;
    <% end %>
  //]]>
  </script>


Rgds,
- matt.

-----Original Message-----
From: ruby-talk@hinv.org [mailto:ruby-talk@hinv.org] 
Sent: 31 March 2007 17:56
To: ruby-talk ML
Subject: updating an RJS template _while_ executing a method

I have a method doing I/O stuff which takes quite a long time.
While this method is processed,
I want the user of my tool to be informed of the current execution state.

For example,
if the method opens a file,
I want my RJS template to render a message such as "opening file XYZ...",
if the method changes to a directory, message would be "cd to ...".

As far as I can tell,
RJS templates are rendered AFTER the corresponding method is executed.
But I want them to run (sort of) synchronously.
Or at least have a way to trigger messages while a method is executed.

Cheers,
  Tom.