B4X

Create JWT Using HS256, HS384, or HS512

See more JSON Web Token (JWT) Examples

Demonstrates how to create a JWT using HS256, HS384, or HS512. (HS256 is JWT's acronym for HMAC-SHA256.) When HMAC is used, the secret is a shared secret (i.e. password) that both client and server know beforehand.

This example also demonstrates how to include time constraints:

• nbf: Not Before Time
• exp: Expiration Time
• iat: Issue At Time

B4X

Dim success As Boolean = False

'  Demonstrates how to create an HMAC JWT using a shared secret (password).

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

Dim jwt As ChilkatJwt
jwt.Initialize

'  Build the JOSE header
Dim jose As ChilkatJsonObject
jose.Initialize
'  Use HS256.  Pass the string "HS384" or "HS512" to use a different algorithm.
success = jose.AppendString("alg", "HS256")
success = jose.AppendString("typ", "JWT")

'  Now build the JWT claims (also known as the payload)
Dim claims As ChilkatJsonObject
claims.Initialize
success = claims.AppendString("iss", "http://example.org")
success = claims.AppendString("sub", "John")
success = claims.AppendString("aud", "http://example.com")

'  Set the timestamp of when the JWT was created to now.
Dim curDateTime As Int = jwt.GenNumericDate(0)
success = claims.AddIntAt(-1, "iat", curDateTime)

'  Set the "not process before" timestamp to now.
success = claims.AddIntAt(-1, "nbf", curDateTime)

'  Set the timestamp defining an expiration time (end time) for the token
'  to be now + 1 hour (3600 seconds)
success = claims.AddIntAt(-1, "exp", curDateTime + 3600)

'  Produce the smallest possible JWT:
jwt.AutoCompact = True

Dim strJwt As String = jwt.CreateJwt(jose.Emit, claims.Emit, "secret")

Log(strJwt)