How to check if a string is base64 valid in PHP

Question

I have a string and want to test using PHP if it's a valid base64 encoded or not.

Answer 1

I realise that this is an old topic, but using the strict parameter isn't necessarily going to help.

Running base64_decode on a string such as "I am not base 64 encoded" will not return false.

If however you try decoding the string with strict and re-encode it with base64_encode, you can compare the result with the original data to determine if it's a valid bas64 encoded value:

if ( base64_encode(base64_decode($data, true)) === $data){     echo '$data is valid'; } else {     echo '$data is NOT valid'; } 

Answer 2

You can use this function:

 function is_base64($s) {       return (bool) preg_match('/^[a-zA-Z0-9\/\r\n+]*={0,2}$/', $s); }