How to get the claims from a JWT in my Flutter Application
JWT tokens are just base64 encoded JSON strings (3 of them, separated by dots):
import 'dart:convert';
Map<String, dynamic> parseJwt(String token) {
final parts = token.split('.');
if (parts.length != 3) {
throw Exception('invalid token');
}
final payload = _decodeBase64(parts[1]);
final payloadMap = json.decode(payload);
if (payloadMap is! Map<String, dynamic>) {
throw Exception('invalid payload');
}
return payloadMap;
}
String _decodeBase64(String str) {
String output = str.replaceAll('-', '+').replaceAll('_', '/');
switch (output.length % 4) {
case 0:
break;
case 2:
output += '==';
break;
case 3:
output += '=';
break;
default:
throw Exception('Illegal base64url string!"');
}
return utf8.decode(base64Url.decode(output));
}
Use 'base64Url.normalize()' function. That's what _decodeBase64() does from the answer above!
String getJsonFromJWT(String splittedToken){
String normalizedSource = base64Url.normalize(encodedStr);
return utf8.decode(base64Url.decode(normalizedSource));
}