issueExpressToken function

String issueExpressToken(JwtExpress claimSet, String hmacKey)

Issues a HMAC SHA-256 signed JWT.

Creates a JWT using the claimSet for the payload and signing it using the hmacKey with the HMAC SHA-256 algorithm.

Throws a JsonUnsupportedObjectError if any of the Claim Values are not suitable for a JWT.

final claimSet = JwtExpress(
  subject: 'kleak',
  issuer: 'teja',
  audience: <String>['example.com', 'hello.com'],
  payload: {'k': 'v'});
  String token = issueExpressToken(claimSet, key);
  print(token);

Implementation

String issueExpressToken(JwtExpress claimSet, String hmacKey) {
  final hmac = Hmac(sha256, hmacKey.codeUnits);

  // Use SplayTreeMap to ensure ordering in JSON: i.e. alg before typ.
  // Ordering is not required for JWT: it is deterministic and neater.
  final header = SplayTreeMap<String, String>.from(
      <String, String>{'alg': 'HS256', 'typ': 'JWT'});

  final String encHdr = B64urlEncRfc7515.encodeUtf8(json.encode(header));
  final String encPld =
      B64urlEncRfc7515.encodeUtf8(json.encode(claimSet.toJson()));
  final String data = '${encHdr}.${encPld}';
  final String encSig =
      B64urlEncRfc7515.encode(hmac.convert(data.codeUnits).bytes);
  return data + '.' + encSig;
}