How can PHP developers ensure that no HTML code or echo statements interfere with the header modification for file downloads?

When sending files for download in PHP, it's important to ensure that no HTML code or echo statements are sent before modifying the headers. This is because headers must be set before any content is sent to the browser. To prevent interference, PHP developers can use output buffering to capture any output and prevent it from being sent prematurely. 

<?php
ob_start(); // Start output buffering

// Set headers for file download
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"example.txt\"");

// Output file contents
echo "File content goes here";

ob_end_flush(); // Flush the output buffer
exit;
?>

Keywords

PHP header modification file downloads ob_start ob_clean

Related Questions