If you wish to find the size of the file you are streaming and use it as your header this is how:
<?php
function write_function($curl_resource, $string)
{
if(curl_getinfo($curl_resource, CURLINFO_SIZE_DOWNLOAD) <= 2000)
{
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Description: File Transfer');
header("Content-Transfer-Encoding: binary");
header("Content-Type: ".curl_getinfo($curl_resource, CURLINFO_CONTENT_TYPE)."");
header("Content-Length: ".curl_getinfo($curl_resource, CURLINFO_CONTENT_LENGTH_DOWNLOAD)."");
}
print $string;
return mb_strlen($string, '8bit');
}
?>
1440 is the the default number of bytes curl will call the write function (BUFFERSIZE does not affect this, i actually think you can not change this value), so it means the headers are going to be set only one time.
write_function must return the exact number of bytes of the string, so you can return a value with mb_strlen.
