Lianja Requires Chilkat v11.0.0+
PRODA Get OAuth2 Access Token using JWT

Demonstrates how to get an OAuth2 access token for the PRODA Australian Government Online Services using a JWT.
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Lianja
llSuccess = .F.

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

//  First create a JWT to be sent in the POST to https://vnd.proda.humanservices.gov.au/mga/sps/oauth/oauth20/token

loPrivKey = createobject("CkPrivateKey")

//  Load an RSA private key from a PEM file.
//  Chilkat provides alternative methods to load from other formats, or to load from a string or binary data.
llSuccess = loPrivKey.LoadEncryptedPemFile("qa_data/pem/rsa_passwd.pem","passwd")
if (llSuccess = .F.) then
    ? loPrivKey.LastErrorText
    release loPrivKey
    return
endif

loJwt = createobject("CkJwt")

//  Build the JOSE header
loJose = createobject("CkJsonObject")
//  Use RS256.  Pass the string "RS384" or "RS512" to use RSA with SHA-384 or SHA-512.
llSuccess = loJose.AppendString("alg","RS256")
llSuccess = loJose.AppendString("typ","JWT")
llSuccess = loJose.AppendString("kid","test-device")

//  Now build the JWT claims (also known as the payload)
loClaims = createobject("CkJsonObject")
llSuccess = loClaims.AppendString("iss","9646844092")
llSuccess = loClaims.AppendString("sub","test-device")
llSuccess = loClaims.AppendString("aud","https://proda.humanservices.gov.au")

//  Set the timestamp of when the JWT was created to now.
lnCurDateTime = loJwt.GenNumericDate(0)
llSuccess = loClaims.AddIntAt(-1,"iat",lnCurDateTime)

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

//  Produce the smallest possible JWT:
loJwt.AutoCompact = .T.

//  Create the JWT token.  This is where the RSA signature is created.
lcJwtToken = loJwt.CreateJwtPk(loJose.Emit(),loClaims.Emit(),loPrivKey)

//  ---------------------------------------------------------------------
//  Build and send the POST, which should look something like this:

//  POST https://vnd.proda.humanservices.gov.au/mga/sps/oauth/oauth20/token HTTP/1.1
//  Content-Type: application/x-www-form-urlencoded
//  Content-Length: 666
//  Host: vnd.proda.humanservices.gov.au
//  
//  grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Ajwt-bearer&assertion=<jwt>&client_id=VendorClient03

loHttp = createobject("CkHttp")

loReq = createobject("CkHttpRequest")
loReq.HttpVerb = "POST"
loReq.ContentType = "application/x-www-form-urlencoded"

//  Add the request params.
loReq.AddParam("grant_type","urn:ietf:params:oauth:grant-type:jwt-bearer")
loReq.AddParam("assertion",lcJwtToken)
loReq.AddParam("client_id","VendorClient03")

loResp = createobject("CkHttpResponse")
llSuccess = loHttp.HttpReq("https://vnd.proda.humanservices.gov.au/mga/sps/oauth/oauth20/token",loReq,loResp)
if (llSuccess = .F.) then
    ? loHttp.LastErrorText
    release loPrivKey
    release loJwt
    release loJose
    release loClaims
    release loHttp
    release loReq
    release loResp
    return
endif

? "Response status code = " + str(loResp.StatusCode)
? "Response body:"
? loResp.BodyStr


release loPrivKey
release loJwt
release loJose
release loClaims
release loHttp
release loReq
release loResp