File size from an remote server

Anon

Newbie question

How do I get the size of a file from an url ??

Anon

You cannot. You would need to implement your own function, which loads the page or file from the remote server (use fopen() and fread()). I would suggest to read the file one bit after another and then using a counter which would end up with the total filesize if you have reached the end of the file.

$fp = fopen($remote_file);
while (!feof($fp)) {
$content = fread($fp, 1);
$t++;
}

$t would output the total amount of bits in the file...

Anon

What if the file is 5 of 10Mb big, waste of good server trafic, there must be another way

Anon

right, there should be a way of checking the content length, in the header.

Anon

I am not sure if it works on remote files,
but you could look at the following php-functions:
fopen();
fstat();

Anon

Yes, you can check the content-length in the header, except that the server is not required to supply this information, so you can't count on it being there in any particular case.

Anon

this doesn't always work. remember, sometimes your browser doesn't "know" the total filesize eighter, it just comes in...

off course, you could first try it that way (headers) and if it doesn't work, load the file the way i described earlier.

Anon

since filesize doesn't work on remote files, it would surprise me if fstat did. fstat() reveils far more information on the file, so I suppose it only works on local files.

Anon

look at the filesize() function in the manual (http://www.php.net/manual/function.filesize.php)

one annotation goes :

About finding the file size of a remote file, I highly doubt that you could access this kind of information on a remote machine. This would be a huge security issue. If you really want to find the size of a file on a remote web server, you could write a socket script to connect to the desired HTTP server and by sending:

HEAD /filefolder/file.jpg HTTP/1.1<CRLF>
Host: www.yourhostname.com<CRLF><CRLF>

Then the webserver should send you the header of that file which contains the header field "Content-Length: ". It's value is the size of the file requested. Note that you need the "Host: " header field if you specify HTTP version 1.1 (HTTP/1.1) or the server will respond with an error. Also, the command HEAD is not supported by all servers. You can use GET instead, but the server will send the header with the file content which will take longer to process.

Check the HTTP RFC for more info on the protocol. If the file is not on a web server, then your on your own. 😉

Seb

Anon

I think that most servers provide you with the filesize when you download. But how do you receive and extract the filesize from the header ??

Anon

Here's a function for parsing remote file information for file size. It returns file size if it can, otherwise it returns 0.

funtion get_file_size ($url)
{
$url = parse_url($url);
$fp = fosckopen($url[host],80,$errno,$errstr,30);
socket_set_blocking($fp, TRUE);

// Can't open a connection //
if (! $fp) { return 0; }

fwrite($fp, "HEAD $url[path] HTTP/1.0\r\nHost: $url[host]\r\n\r\n");
fclose($fp);
preg_match("/content-length:\s?(\d+)/i", $result, $match);
return $match[1];
}

Anon

Whoops...here it is...

function get_file_size ($url)
{
$url = parse_url($url);
$fp = fsockopen($url[host],80,$errno,$errstr,30);
socket_set_blocking($fp, TRUE);

// Can't open a connection //
if (! $fp) { return 0; }

fwrite($fp, "HEAD $url[path] HTTP/1.0\r\nHost: $url[host]\r\n\r\n");
for($result = ""; !feof($fp); $result .= fread($fp, 10000000));
fclose($fp);

if (preg_match("/content-length:\s?(\d+)/i", $result, $match)){
return $match[1];
} else {
return 0;
}
}