Hello. I was wondering if is is possible to send output from application ran by php to client.
For example i have application that outputs:
Hello world
And after 10 seconds it outputs
10 seconds passed
I'd like to know if it is possible to send "Hello word" and "10 seconds passed" to client without waiting until whole program finishes its job. Client would receive "Hello world" first and after 10 seconds second output.
Thank you.
I think you should do this with javascript. It's totally unnecessary to use cpu-cycles on the server until all of your requirements are that show time passed.
Usually, a client pulls content from the server. If you want to push from the server to the client, you need to look into push technologies like Comet. There is not too much available for PHP though. Periodically pushing with the PHP script terminating inbetween requires a Message Queue.
Your title says "Asynchronous external aplication execution". By this, you would mean something that will execute a program from your PHP script, yet continue on its own process and not hang PHP page load. You may want passthru() specifically setting the command to output to a local file rather than your script (personally not tested, though the PHP manual says you can), or pcntl_fork() to split off your script into a separate process which will handle the program execution on the side. However, double-sending to a browser after it had already disconnected from your server and expecting it to display your uninvited message is impossible unless you install a trojan on the client which will auto-accept your second, new tcp forced connection.
But, if you want a progress message for your page load, simply echo "still loading..." anywhere along a number of for or while loops. File download progress bars on the other hand cannot be dealt with in PHP. Echoing "still loading..." in the middle of the download will corrupt the file. At the moment, I'm not aware of any facility to do this using any PHP, Javascript, or VB method, except in the browsers own API (if documented) if the client allows it by installing a plugin you authored. But why, when browsers already have built-in progress bars?
I don't understand your application, but for batch processing this comes to mind:
php hello-world.php | php client.php
To scale it, use Hadoop.