PHP base64_encode在字符串末尾添加奇怪的字符

Question

I´m using an array, which I encode into json, than into BASE64, save it on a Cookie, to be later on retrieved. The actual string is:

{"insert":0,"delete":0}

In PHP I have:

$Sync = json_encode($update);
setcookie('Sync',strtr(base64_encode($Sync), '+/', '-_'), 0, "/");

The Cookie is being stored as:

eyJpbnNlcnQiOjEsImRlbGV0ZSI6MH0%3D

That final "%3D" should be "=" so to fill the rest of the base64, nad therefore return strange characters, but I can´t get it right. Any ideas? Thanks in advance

Answer 1

Within the docs on php.net (http://php.net/manual/en/function.base64-encode.php#103849) the top comment provides two functions that should help you (similar to your implementation as well :))

For anyone interested in the 'base64url' variant encoding, you can use this pair of functions:

<?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)); 
} 
?>

Within your implementation, it looks like you need to wrap strtr(base64_encode($Sync), '+/', '-_'), 0, "/") with rtrim, like so:

rtrim(strtr(base64_encode($Sync), '+/', '-_'), 0, "/"), '=')

Results: https://3v4l.org/5D1Mk