How to find the download size of a file in PHP?

Answer 1

Using Content-Length Header
we can actually download the file ourselves and then just get the download size for that URL. we can use cURL. Once we download the resource, we can retrieve the download size using the CURLINFO_SIZE_DOWNLOAD parameter. So, using this approach, we can come up with this code:

function get_remote_file_size($url) {

 $headers = get_headers($url, 1);

    if (isset($headers['Content-Length'])) 
       return $headers['Content-Length'];

    //checks for lower case "L" in Content-length:
    if (isset($headers['Content-length'])) 
       return $headers['Content-length'];

//the code below runs if no "Content-Length" header is found:


    $c = curl_init();
    curl_setopt_array($c, array(
        CURLOPT_URL => $url,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_HTTPHEADER => array('User-Agent: Mozilla/5.0 
        (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1.3) 
        Gecko/20090824 Firefox/3.5.3'),
        ));
    curl_exec($c);

    $size = curl_getinfo($c, CURLINFO_SIZE_DOWNLOAD);

    return $size;

    curl_close($c);

}