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phpjqueryajax

How do I close a connection early?

I'm attempting to do an AJAX call (via JQuery) that will initiate a fairly long process. I'd like the script to simply send a response indicating that the process has started, but JQuery won't return the response until the PHP script is done running.

I've tried this with a "close" header (below), and also with output buffering; neither seems to work. Any guesses? or is this something I need to do in JQuery?

<?php

echo( "We'll email you as soon as this is done." );

header( "Connection: Close" );

// do some stuff that will take a while

mail( '[email protected]', "okay I'm done", 'Yup, all done.' );

?>
Solution

  • The following PHP manual page (incl. user-notes) suggests multiple instructions on how to close the TCP connection to the browser without ending the PHP script:

    Supposedly it requires a bit more than sending a close header.

    OP then confirms: yup, this did the trick: pointing to user-note #71172 (Nov 2006) copied here:

    Closing the users browser connection whilst keeping your php script running has been an issue since [PHP] 4.1, when the behaviour of register_shutdown_function() was modified so that it would not automatically close the users connection.

    sts at mail dot xubion dot hu Posted the original solution:

    <?php
header("Connection: close");
ob_start();
phpinfo();
$size = ob_get_length();
header("Content-Length: $size");
ob_end_flush();
flush();
sleep(13);
error_log("do something in the background");
?>

    Which works fine until you substitute phpinfo() for echo('text I want user to see'); in which case the headers are never sent!

    The solution is to explicitly turn off output buffering and clear the buffer prior to sending your header information. Example:

    <?php
ob_end_clean();
header("Connection: close");
ignore_user_abort(true); // just to be safe
ob_start();
echo('Text the user will see');
$size = ob_get_length();
header("Content-Length: $size");
ob_end_flush(); // Strange behaviour, will not work
flush(); // Unless both are called !
// Do processing here 
sleep(30);
echo('Text user will never see');
?>

    Just spent 3 hours trying to figure this one out, hope it helps someone :)

    Tested in:

    • IE 7.5730.11
    • Mozilla Firefox 1.81

    Later on in July 2010 in a related answer Arctic Fire then linked two further user-notes that were-follow-ups to the one above: