stop a curl transfer in the middle

you can return false or something what is not length of currently downloaded data from callback function to abort curl

If the problem is that is taking too long to execute the curl, you could set a time, example

<?php$c = curl_init('http://slow.example.com/');curl_setopt($c, CURLOPT_RETURNTRANSFER, true);curl_setopt($c, CURLOPT_CONNECTTIMEOUT, 15);$page = curl_exec($c);curl_close($c);echo $page;

I had a similar problem that needed me to be able to stop a curl transfer in the middle. This is easily in my personal top ten of 'dirty hacks that seem to work' of all time.

Create a curl read function that knows when it's time to cancel the upload.

function curlReadFunction($ch, $fileHandle, $maxDataSize){    if($GLOBALS['abortTransfer'] == TRUE){        sleep(1);        return "";    }    return fread($fileHandle, $maxDataSize);}

And tell Curl to stop if the data read rate drops too low for a certain amount of time.

curl_setopt($ch, CURLOPT_READFUNCTION, 'curlReadFunction');curl_setopt($ch, CURLOPT_LOW_SPEED_LIMIT, 1024);curl_setopt($ch, CURLOPT_LOW_SPEED_TIME, 5);

This will cause the curl transfer to abort during the upload. Obviously not ideal but it seems to work.