PHP rawurldecode Function and Custom UTF-8 URL Decoding

PHP provides the rawurldecode() function to decode URL‑encoded strings, converting each “%xx” sequence back to its original character.

The function signature is string rawurldecode ( string $str ), where $str is the URL to decode, and it returns the decoded string.

Example usage:

<?php
echo rawurldecode('foo%20bar%40baz');
?>

The output is // foo bar@baz.

Note: the result of rawurldecode() (and urldecode()) is UTF‑8 encoded; if the page is not UTF‑8, you must convert the string before displaying.

When the URL contains non‑standard “%unnnn” sequences, the built‑in functions cannot decode them. The article provides a custom utf8RawUrlDecode($source) function that iterates through the string, handles Unicode “%uXXXX” sequences and escaped ASCII “%XX” sequences, builds the decoded string, and returns it.

The custom function uses substr(), hexdec(), chr(), and utf8_encode() to translate the encoded parts into proper characters.