Are there potential runtime issues with using "readfile" for very large files in PHP, and does the script continue running until the download is complete?

Using "readfile" for very large files in PHP can potentially cause memory issues as the entire file is read into memory before being output. To avoid this, it's recommended to use "fpassthru" instead, which streams the file to the output buffer without loading it all into memory. Additionally, the script will continue running until the download is complete, so it's important to consider the potential impact on server resources. 

$file = 'path/to/large/file.zip';

header('Content-Description: File Transfer');
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="' . basename($file) . '"');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($file));

$handle = fopen($file, 'rb');
fpassthru($handle);
fclose($handle);

Keywords

readfile runtime issues large files PHP download

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