Is readfile() a suitable method for downloading large files in PHP, and what are the performance implications?

Using readfile() to download large files in PHP is not ideal as it loads the entire file into memory before sending it to the client, which can lead to memory exhaustion for very large files. A better approach is to use fopen() and fread() to read and output the file in smaller chunks, reducing memory usage and improving performance. 

<?php
$file = 'path/to/large/file.zip';

// Set appropriate headers
header('Content-Type: application/octet-stream');
header('Content-Disposition: attachment; filename="' . basename($file) . '"');
header('Content-Length: ' . filesize($file));

// Open the file for reading
$handle = fopen($file, 'rb');

// Output the file in chunks
while (!feof($handle)) {
    echo fread($handle, 8192);
}

// Close the file handle
fclose($handle);

Keywords

readfile large files performance implications PHP download

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