src/includes/classes/Core/Utils/Base64.php
public function urlSafeDecode(string $base64_url_safe, array $url_unsafe_chars = ['+', '/'], array $url_safe_chars = ['-', '_'], string $trim_padding_chars = '='): string
    {
        $string = isset($trim_padding_chars[0]) ? rtrim($base64_url_safe, $trim_padding_chars) : $base64_url_safe;
        $string = isset($trim_padding_chars[0]) ? str_pad($string, strlen($string) % 4, '=', STR_PAD_RIGHT) : $string;
        $string = str_replace($url_safe_chars, $url_unsafe_chars, $string);

        if (!is_string($string = base64_decode($string, true))) {
            throw $this->c::issue('Base64 decoding failure.');
        }
        return $string;
    }
public function urlSafeDecode(string $base64_url_safe, array $url_unsafe_chars = ['+', '/'], array $url_safe_chars = ['-', '_'], string $trim_padding_chars = '='): string
    {
        $string = isset($trim_padding_chars[0]) ? rtrim($base64_url_safe, $trim_padding_chars) : $base64_url_safe;
        $string = isset($trim_padding_chars[0]) ? str_pad($string, strlen($string) % 4, '=', STR_PAD_RIGHT) : $string;
        $string = str_replace($url_safe_chars, $url_unsafe_chars, $string);

        if (!is_string($string = base64_decode($string, true))) {
            throw $this->c::issue('Base64 decoding failure.');
        }
        return $string;
    }
Base64 URL-safe decoding.

@since 150424 Initial release.

@param string $base64_url_safe    Input string to be base64 decoded.
@param array  $url_unsafe_chars   Optional array of un-safe characters. Defaults to: `['+', '/']`.
@param array  $url_safe_chars     Optional array of safe character replacements. Defaults to: `['-', '_']`.
@param string $trim_padding_chars Optional string of padding chars to right-trim. Defaults to: `=`.

@throws Exception If the call to `base64_decode()` fails.

@return string The decoded string value.