How to properly use urlencode and urldecode in Phalcon?

What you need first is to provide more details. You use GET http method for data exchange, where data is encrypted in a binary form and encoded with base64, and what exact issue do you have?

$encoded = urlencode( base64_encode( $str ) );
$decoded = base64_decode( urldecode( $encoded ) );

Here are simple functions that i use to transfer encoded information. It is url safe.

private static $cryptKey = 'i$a^&/:%2_z10ROQ<@{(e=*!<7u|rI~0';

public static function encodeString($string)
{
    $crypt = new \Phalcon\Crypt();
    return $crypt->encryptBase64($string, self::$cryptKey, true);
}

public static function decodeString($string)
{
    $crypt = new \Phalcon\Crypt();
    return $crypt->decryptBase64($string, self::$cryptKey, true);
}

And example of course:

$string = 'Hello it is me Nikolay';

$encoded = \Helpers\Tools::encodeString($string);
echo $encoded; // EfLYhEcnsGUiXZ8LZ30uH2DuZMfVmcmuDuZm-tG8w1QO2zDPhkiDf315J11v001OeEJAjS6CwiDB7Ve8B_zp7g==

$decoded = \Helpers\Tools::decodeString($encoded);
echo $decoded; // Hello it is me Nikolay

You can also avoid base64, and use hexadecimal notation/convert both binary and text data and send it via HTTP GET.

  //Before send
        $str = 'This is binary data or \0 terminated array of bytes.';
        //convert it to hexadecimal
        $hex = bin2hex($str); //send $hex via HTTP GET method
// ###########################################
        //After fetch
        $decodeHex = pack('H*', $hex); //or simply $_GET['data'] instead of my test $hex variable

I use this approach while connecting to mainframe upstream services which does not support base64 or json :)

Hexadecimal notation is supported on any platform out there.

In the same php file it has always worked well. The problem is when e-url special characters

Here are simple functions that i use to transfer encoded information. It is url safe.

private static $cryptKey = 'i$a^&/:%2_z10ROQ<@{(e=*!<7u|rI~0';

public static function encodeString($string)
{
   $crypt = new \Phalcon\Crypt();
   return $crypt->encryptBase64($string, self::$cryptKey, true);
}

public static function decodeString($string)
{
   $crypt = new \Phalcon\Crypt();
   return $crypt->decryptBase64($string, self::$cryptKey, true);
}

And example of course:

$string = 'Hello it is me Nikolay';

$encoded = \Helpers\Tools::encodeString($string);
echo $encoded; // EfLYhEcnsGUiXZ8LZ30uH2DuZMfVmcmuDuZm-tG8w1QO2zDPhkiDf315J11v001OeEJAjS6CwiDB7Ve8B_zp7g==

$decoded = \Helpers\Tools::decodeString($encoded);
echo $decoded; // Hello it is me Nikolay

To me they helped me I run this

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));
}

@jeiel if you generate the string with my functions you will not have problems to send/receive via URL. The only difference to yours is that it is a bit more secure.