Xojo Plugin

Get Access Token using a Pre-Created JSON Web Token

See more ABN AMRO Examples

Demonstrates how to get an access token using a pre-created JSON Web Token (JWT). Xojo Plugin

Dim success As Boolean
success = False

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

// We're going to duplicate this CURL statement:
// curl -X POST https://api-sandbox.abnamro.com/v1/oauth/token \
// -H "Content-Type: application/x-www-form-urlencoded" \
// -H "API-Key: xxxxxx" \
// -d 'client_assertion_type=urn:ietf:params:oauth:client-assertion-type:jwt-bearer&grant_type=client_credentials&client_assertion=eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ4eHh4eHgiLCJleHAiOiIxNDk5OTQ3NjY4IiwiaXNzIjoibWUiLCJhdWQiOiJodHRwczovL2F1dGgtc2FuZGJveC5hYm5hbXJvLmNvbS9vYXV0aC90b2tlbiJ9.jGwHKG_YjgKpR8NPpaLu6nJ97obeP2vcxg6fOWBKdJ0&scope=tikkie'

// Load our pre-creaed private key PEM file.
// Note: Please share your public key along with your app name and developer email id at api.support@nl.abnamro.com. 
// Token generation will not work unless public key is associated with your app.
Dim privkey As New Chilkat.PrivateKey

success = privkey.LoadPemFile("qa_data/pem/abnAmroPrivateKey.pem")
If (success = False) Then
    System.DebugLog(privkey.LastErrorText)
    Return
End If

// Create the JWT.
Dim jwt As New Chilkat.Jwt

// Create the header:
// {
//     "typ": "JWT",
//     "alg": "RS256"
// }
Dim jsonHeader As New Chilkat.JsonObject
success = jsonHeader.UpdateString("typ","JWT")
success = jsonHeader.UpdateString("alg","RS256")

// Create the payload:
// {
//     "nbf": 1499947668,
//     "exp": 1499948668,
//     "iss": "me",
//     "sub": "anApiKey",
//     "aud": "https://auth-sandbox.abnamro.com/oauth/token"
// }
Dim jsonPayload As New Chilkat.JsonObject

Dim curDateTime As Int32
curDateTime = jwt.GenNumericDate(0)

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

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

success = jsonPayload.UpdateString("iss","me")
success = jsonPayload.UpdateString("sub","anApiKey")
success = jsonPayload.UpdateString("aud","https://auth-sandbox.abnamro.com/oauth/token")

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

Dim jwtStr As String
jwtStr = jwt.CreateJwtPk(jsonHeader.Emit(),jsonPayload.Emit(),privkey)
If (jwt.LastMethodSuccess = False) Then
    System.DebugLog(jwt.LastErrorText)
    Return
End If

Dim http As New Chilkat.Http

Dim req As New Chilkat.HttpRequest
req.AddParam "client_assertion_type","urn:ietf:params:oauth:client-assertion-type:jwt-bearer"
req.AddParam "grant_type","client_credentials"
req.AddParam "client_assertion",jwtStr
req.AddParam "scope","tikkie"

req.HttpVerb = "POST"
req.ContentType = "application/x-www-form-urlencoded"

Dim resp As New Chilkat.HttpResponse
success = http.HttpReq("https://api-sandbox.abnamro.com/v1/oauth/token",req,resp)
If (success = False) Then
    System.DebugLog(http.LastErrorText)
    Return
End If

If (resp.StatusCode <> 200) Then
    System.DebugLog(resp.BodyStr)
    Return
End If

// Get the JSON result:
// {
//     "access_token": "{your access token}",
//     "expires_in": "{duration of validity in seconds}",
//     "scope": "{scope(s) for which the access token is valid}",
//     "token_type": "{it is always Bearer}"
// }
Dim json As New Chilkat.JsonObject
success = json.Load(resp.BodyStr)
System.DebugLog("access_token: " + json.StringOf("access_token"))
System.DebugLog("token_type: " + json.StringOf("token_type"))
System.DebugLog("expires_in: " + json.StringOf("expires_in"))
System.DebugLog("scope: " + json.StringOf("scope"))