Re: asynchronous launch of a script

On Tue, Jun 28, 2011 at 8:16 PM, David Harkness <david.h@highgearmedia.com>wrote: > On Sun, Jun 26, 2011 at 7:42 PM, Tamara Temple <tamouse.lists@gmail.com > >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/