(PowerShell) Get Access Token using a Pre-Created JSON Web Token

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

For more information, see https://developer.abnamro.com/get-started#headingFive

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# 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.
$privkey = New-Object Chilkat.PrivateKey

$success = $privkey.LoadPemFile("qa_data/pem/abnAmroPrivateKey.pem")
if ($success -eq $false) {
    $($privkey.LastErrorText)
    exit
}

# Create the JWT.
$jwt = New-Object Chilkat.Jwt

# Create the header:
# {
#     "typ": "JWT",
#     "alg": "RS256"
# }
$jsonHeader = New-Object Chilkat.JsonObject
$jsonHeader.UpdateString("typ","JWT")
$jsonHeader.UpdateString("alg","RS256")

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

$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)

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

# Produce the smallest possible JWT:
$jwt.AutoCompact = $true

$jwtStr = $jwt.CreateJwtPk($jsonHeader.Emit(),$jsonPayload.Emit(),$privkey)
if ($jwt.LastMethodSuccess -ne $true) {
    $($jwt.LastErrorText)
    exit
}

$http = New-Object Chilkat.Http

$req = New-Object 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")

$resp = $http.PostUrlEncoded("https://api-sandbox.abnamro.com/v1/oauth/token",$req)
if ($http.LastMethodSuccess -eq $false) {
    $($http.LastErrorText)
    exit
}

if ($resp.StatusCode -ne 200) {
    $($resp.BodyStr)

    exit
}

# 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}"
# }
$json = New-Object Chilkat.JsonObject
$json.Load($resp.BodyStr)
$("access_token: " + $json.StringOf("access_token"))
$("token_type: " + $json.StringOf("token_type"))
$("expires_in: " + $json.StringOf("expires_in"))
$("scope: " + $json.StringOf("scope"))