Should You Use `exit()` After a `Location:` Header in PHP?

Should exit() Be Used After Location: header?

After invoking the header function for redirection, it's crucial to decide whether to call exit() or not. This question arises because header does not automatically end script execution.

Why Call exit()?

Using exit() after header is highly recommended for the following reasons:

• Prevention of Further Code Execution: Without exit(), the script continues to execute code after the redirect header is set. This can lead to unintended side effects or unnecessary resource consumption.
• Clear Script Output: exit() forces the script to stop execution and prevents additional output from being sent to the browser. This ensures a cleaner redirect experience.

Example Usage:

As shown in the given example, exit() should be called immediately after setting the Location header:

<?php // fileA
$urlFailToGoTo = '/formerror.php';

if (sth) {
    header(sprintf("Location: %s", $urlFailToGoTo));
    exit();
}

Avoid Using return:

Using return in place of exit() here is incorrect. return normally ends a function or method, but in this case, the script is a standalone program that doesn't return to any caller. exit() is the appropriate choice for terminating script execution cleanly.

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