Module licenseware.common.validators.validate_base64

import base64
from marshmallow import ValidationError


def _valid_base64(sb: str):

        try:
                if not sb: return True
                if isinstance(sb, str):
                        # If there's any unicode here, an exception will be thrown and the function will return false
                        sb_bytes = bytes(sb, 'ascii')
                elif isinstance(sb, bytes):
                        sb_bytes = sb
                else:
                        raise ValueError("Argument must be string or bytes")
                
                return base64.b64encode(base64.b64decode(sb_bytes)) == sb_bytes
                
        except Exception:
                return False


def validate_base64(value: str):        
        
        if not _valid_base64(value):
                raise ValidationError("Not a valid base64 string")