(Tcl) ABN AMRO Create Signed JSON Web Token

Demonstrates how to create a signed JWT to be used for authenticating requests to the ABN AMRO REST API's.

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

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load ./chilkat.dll

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

# Create public/private key pair (RSA)
set rsa [new_CkRsa]

# Generate a 2048-bit key.
set success [CkRsa_GenerateKey $rsa 2048]
if {$success != 1} then {
    puts [CkRsa_lastErrorText $rsa]
    delete_CkRsa $rsa
    exit
}

# Export the key to PEM files.
# Write one PEM file for the private key, and one for the public key.
# privkey is a CkPrivateKey
set privkey [CkRsa_ExportPrivateKeyObj $rsa]
set success [CkPrivateKey_SavePemFile $privkey "qa_data/pem/abnAmroPrivateKey.pem"]

# pubkey is a CkPublicKey
set pubkey [CkRsa_ExportPublicKeyObj $rsa]
set success [CkPublicKey_SavePemFile $pubkey 1 "qa_data/pem/abnAmroPublicKey.pem"]
# 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.

# Create the JWT.
set jwt [new_CkJwt]

# Create the header:
# {
#     "typ": "JWT",
#     "alg": "RS256"
# }
set jsonHeader [new_CkJsonObject]

CkJsonObject_UpdateString $jsonHeader "typ" "JWT"
CkJsonObject_UpdateString $jsonHeader "alg" "RS256"

# Create the payload:
# {
#     "nbf": 1499947668,
#     "exp": 1499948668,
#     "iss": "me",
#     "sub": "anApiKey",
#     "aud": "https://auth-sandbox.abnamro.com/oauth/token"
# }
set jsonPayload [new_CkJsonObject]

set curDateTime [CkJwt_GenNumericDate $jwt 0]

# Set the "not process before" timestamp to now.
set success [CkJsonObject_AddIntAt $jsonPayload -1 "nbf" $curDateTime]

# Set the timestamp defining an expiration time (end time) for the token
# to be now + 1 hour (3600 seconds)
set success [CkJsonObject_AddIntAt $jsonPayload -1 "exp" [expr $curDateTime + 3600]]

CkJsonObject_UpdateString $jsonPayload "iss" "me"
CkJsonObject_UpdateString $jsonPayload "sub" "anApiKey"
CkJsonObject_UpdateString $jsonPayload "aud" "https://auth-sandbox.abnamro.com/oauth/token"

# Produce the smallest possible JWT:
CkJwt_put_AutoCompact $jwt 1

set jwtStr [CkJwt_createJwtPk $jwt [CkJsonObject_emit $jsonHeader] [CkJsonObject_emit $jsonPayload] $privkey]
if {[CkJwt_get_LastMethodSuccess $jwt] != 1} then {
    puts [CkJwt_lastErrorText $jwt]
    delete_CkRsa $rsa
    delete_CkJwt $jwt
    delete_CkJsonObject $jsonHeader
    delete_CkJsonObject $jsonPayload
    exit
}

delete_CkPrivateKey $privkey

delete_CkPublicKey $pubkey

# Here is the JWT:
puts "$jwtStr"

delete_CkRsa $rsa
delete_CkJwt $jwt
delete_CkJsonObject $jsonHeader
delete_CkJsonObject $jsonPayload