From: Jeremy McAnally <jeremymcanally@...>
Date: 2007-04-03T10:42:21+09:00
Subject: Re: updating an RJS template _while_ executing a method

My suggestion: run your task using BackgrounDrb or something similar.
Use periodically_call_remote to poll the execution's status until it's
completed.

--Jeremy

On 4/2/07, ruby-talk@hinv.org <ruby-talk@hinv.org> wrote:
> Hi Matt,
>
> As you suggested I put the "poll_message"-div + JS-code + periodically_...
> inside a partial rendered at startup.
>
> I also got rid of the RJS-template in exchange for your "respond_to" thing
> But here is the thing:
> my io_process-method looks sort of like this:
>
> def io_method
>   session[:message] = "starting io..."
>   # ...
>   if (blah)
>     session[:message] = "finished"
>   else
>     session[:message] = "an error occurred!"
>   end
>   respond_to do |format|
>     format.js { render :update do |page|
>       page.insert_html :bottom, 'poll_message', :partial => 'message'
>     end
>   }
>   session[:message] = nil
> end
>
> my partial "_message.rhtml" just calls "<%= session[:message] %>"
>
> So when the interpreter gets to "respond_to",
> it only renders the last message defined by the io_method.
>
> Also the message is rendered after io_method is done.
> So I am actually where I started from:
> the template messages get rendered after the controller method is done.
>
> Thanks for your help!
>
> Cheers,
>   Tom.
>
> ---------------------------------
> On Mon, 2 Apr 2007 19:57:54 +0900
> "Matthieu Stone" <matt.stone@cityticketexchange.com> wrote:
>
> > Hi Tom,
> >
> > I think that this will answer your questions.
> >
> > To get rid of the firebug message, just make sure that this routine
> >
> > ><div id="poll_message"><%= session[:message] %></div>
> > >   <script type="text/javascript">
> > >   //<![CDATA[
> > >     <% if @session[:message] && !@session[:message].blank? %>
> > >       poll_message = true;
> > >     <% else %>
> > >       Poll_message = false;
> > >     <% end %>
> > >   //]]>
> > >   </script>
> >
> > Is rendered in the page before the periodically_call_update routine, it's
> > easier to place this in a partial, then you can it via RJS in any controller
> > method. I've added the poll_message div to make things a little more
> > explicit.
> >
> >     session[:message] = "let's get it started.."
> >
> >     respond_to do |format|
> >       format.js { render :update do |page|
> >                       page.replace 'poll_message', :partial =>
> > 'poll_message'
> >                       page.visual_effect :highlight, 'poll_message',
> >                                          :duration   => 1,
> >                                          :startcolor => '"#FFCCFF"',
> >                                          :endcolor   => '"#FFFFCC"'
> >                   end
> >                 }
> >     end
> >
> >
> > I use the respond_to mechanism to update div's on the page, rather than .rjs
> > files. I don't need to specify :update => some_div in the
> > periodically_call_remote routine & I can do other things, such as highlight
> > the updated message or update another part of the screen using logic in the
> > controller. There are upsides & downsides to doing things this way, I just
> > find it easier to do it in the controller as it keeps all my page logic in
> > the one place.
> >
> > rgds,
> > - matt.
> >
> > -----Original Message-----
> > From: ruby-talk@hinv.org [mailto:ruby-talk@hinv.org]
> > Sent: 02 April 2007 11:17
> > To: ruby-talk ML
> > Subject: Re: updating an RJS template _while_ executing a method
> >
> > Hey Matt,
> >
> > what I still don't understand is
> > where to turn "poll_message" on and off using your JS-code?
> > Or: what do you mean with "...in a RJS update..."?
> >
> > -> Inside the RJS-template of "my_io_process"?
> > That throws quite a few errors.
> >
> > -> Using inline RJS rendering inside my controller?
> > (which shouldn't work while also using an RJS template)
> >
> > -> somewhere else..?
> >
> > Also:
> > Do I need to specify a ":update => 'my_div'"
> > within periodically_call_remote?
> > When I put this call inside my layout,
> > Firebug yells at me: "poll_message not defined"...
> > Is a "var poll_message = false" fine?
> >
> > Thanks for your help!
> > Cheers,
> >   Tom.
> >
> > ---------------------------------
> > On Sun, 1 Apr 2007 04:43:45 +0900
> > "Matthieu Stone" <matt.stone@cityticketexchange.com> wrote:
> >
> > > 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.
> > >
> > >
> >
> >
>
>


-- 
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