On Tue, Jun 28, 2011 at 8:16 PM, David Harkness
<david.h@xxxxxxxxxxxxxxxxx>wrote:
> On Sun, Jun 26, 2011 at 7:42 PM, Tamara Temple <tamouse.lists@xxxxxxxxx
> >wrote:
>
> > How do I launch a php script from another running php script
> > asynchronously?
> >
>
> You can perform the long-running job in the same process that handles the
> request by sending appropriate headers. We use this to run reports that
> take
> ten minutes without making the user keep the browser tab open. Call this
> method before starting the job:
>
> /**
> * Effectively causes PHP to keep running after flushing everything and
> closing the client connection
> *
> * @param mixed $status JSON-encoded and sent to the client
> */
> public function flushAndCloseConnection($status) {
> // disable any apache or php gzipping
> if (function_exists('apache_setenv')) {
> apache_setenv('no-gzip', 1);
> }
> ini_set('zlib.output_compression', 0);
> // Tell the server and client we intend for it to disconnect
> ignore_user_abort(true);
> // Tell the client we are done!
> header('Connection: close');
> header('Content-type: application/json');
> $json = json_encode($status);
> header('Content-Length: ' . strlen($json));
> echo $json;
> flush();
> }
>
> In our case we send a JSON status string ("ok") as well.
>
While this will work, I would caution against doing this, especially when
using Apache as the web server. Keeping an HTTP request handler process
occupied with an offline task is a substantial waste of resources. Far
better to offload that work to a separate process so as to free up the
request handler so it's available to handle another incoming request.
Another option is to fork the process using pcntl_fork() [1]. I haven't used
> this in PHP before so I can't give an example.
>
Forking an HTTP request handler can lead to some very unwelcome
side-effects. I'd urge you not to do this. It may appear to work for a
while, but I guarantee you'll live to regret it.
-Stuart
--
Stuart Dallas
3ft9 Ltd
http://3ft9.com/
