[cgiapp] Streaming Status Updates for a Long-running Run Mode

[eric.berg at barclayscapital.com]

Thanks, Michael.  Good point about AJAX not returning until the entire
request is done.

The approach I'm working on now is to have a global status hash for each
file being processed, which I'll update as I run each subprocess and
when each completes.  Then I've thrown in a quick run mode that simply
sends that hash back as JSON and I'm putting some logic into my page to
periodically make a request for this runmode so I can update the page
with current status info.

On a related note, is there a way to have cgiapp send content back to
the client during the processing of a run mode instead of at the end
when the rm returns?

Eric

> -----Original Message-----
> From: cgiapp-bounces at lists.openlib.org 
> [mailto:cgiapp-bounces at lists.openlib.org] On Behalf Of Michael Peters
> Sent: Wednesday, October 07, 2009 11:28 AM
> To: CGI Application
> Subject: Re: [cgiapp] Streaming Status Updates for a 
> Long-running Run Mode
> 
> On 10/07/2009 10:33 AM, eric.berg at barclayscapital.com wrote:
> 
> > How can I update my web page with status from this run mode 
> while the
> > subprocesses are running?
> 
> There's a couple of different ways this can be done. The best is 
> definitely not the easiest but it means creating a separate 
> offline job 
> queue that can run these processes and keep their status in a shared 
> location (like a DB, etc). Then your rm just adds a job to 
> the queue and 
> returns. Then when you're checking on the status via Ajax you need to 
> have another rm that simply checks on the status of the job 
> and returns 
> a flag that could mean success, failure, or try again later 
> (still working).
> 
> Unfortunately, since you are using Ajax, you can't use the 
> standard NPH 
> approach and just periodically print something to the browser 
> while it's 
> working. Ajax requests don't return (in the javascript) until 
> the entire 
> request is done and it will probably timeout on you.
> 
> -- 
> Michael Peters
> Plus Three, LP
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