General developer forum

I just discovered we are using readfile() in a few places in the code. Readfile is now being affected by a bug in some PHP5 versions -- this has been discussed in other threads -- where readfile serves only the first 2MB and then gives up.

Even when it works correctly, it loads the whole file into memory. So you are bound by PHP's memory limits in the filesizes you can server, and PHP doesn't release memory, messing up your memory management. Argh.

A better replacement for readfile looks roughly like:

function readfile_chunked($filename,$retbytes=true) {
$chunksize = 1*(1024*1024); // how many bytes per chunk
$buffer = '';
$cnt =0;
// $handle = fopen($filename, 'rb');
$handle = fopen($filename, 'rb');
if ($handle === false) {
return false;
}
while (!feof($handle)) {
$buffer = fread($handle, $chunksize);
echo $buffer;
if ($retbytes) {
$cnt += strlen($buffer);
}
}
$status = fclose($handle);
if ($retbytes && $status) {
return $cnt; // return num. bytes delivered like readfile() does.
}
return $status;

}

I am mostly concerned about send_file() in lib/filelib.php -- we'll be testing this replacement today.