base64url functionality for php

base64url.php

<?php

function base64url_encode($data) { 
    return rtrim(strtr(base64_encode($data), '+/', '-_'), '='); 
} 

function base64url_decode($data) { 
    return base64_decode(str_pad(strtr($data, '-_', '+/'), strlen($data) % 4, '=', STR_PAD_RIGHT)); 
}

What lp0 said is correct -- you don't need to pad the string before decoding it. Thus, the decode function should really be:

function base64url_decode($data) {
    return base64_decode(strtr($data, '-_', '+/'));
}

I've unit tested this.

Since base64_decode() does not bother about "=" signs at the end, you can omit str_pad(..) as remarked by lp0 and mnpenner above.

However, if one will do the padding "manually" (for what reason ever), the pad_length in str_pad() should look like: strlen($data) + (4 - strlen($data) % 4) % 4. @xsddz: Your code is close, but the case when strlen($data) % 4 = 0 should not insert any "=" at the end (your code appends 4x "=" in this case).

is there update on this with php >= 7?
https://www.php.net/manual/en/function.base64-encode.php#123098

why fiddle with base64 why dont you just pass it on rawurlencode/rawurldecode?