How do I close a connection early?

Question

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 star

Answer 1

It's necessary to send these 2 headers:

Connection: close
Content-Length: n (n = size of output in bytes )

Since you need know the size of your output, you'll need to buffer your output, then flush it to the browser:

// buffer all upcoming output
ob_start();
echo "We'll email you as soon as this is done.";

// get the size of the output
$size = ob_get_length();

// send headers to tell the browser to close the connection
header("Content-Length: $size");
header('Connection: close');

// flush all output
ob_end_flush();
ob_flush();
flush();

// if you're using sessions, this prevents subsequent requests
// from hanging while the background process executes
if (session_id()) session_write_close();

/******** background process starts here ********/

Also, if your web server is using automatic gzip compression on the output (ie. Apache with mod_deflate), this won't work because actual size of the output is changed, and the Content-Length is no longer accurate. Disable gzip compression the particular script.

For more details, visit http://www.zulius.com/how-to/close-browser-connection-continue-execution