Delphi DLL

PRODA Get OAuth2 Access Token using JWT

See more PRODA Examples

Demonstrates how to get an OAuth2 access token for the PRODA Australian Government Online Services using a JWT. Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Jwt, HttpResponse, HttpRequest, JsonObject, PrivateKey, Http;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
privKey: HCkPrivateKey;
jwt: HCkJwt;
jose: HCkJsonObject;
claims: HCkJsonObject;
curDateTime: Integer;
jwtToken: PWideChar;
http: HCkHttp;
req: HCkHttpRequest;
resp: HCkHttpResponse;

begin
success := False;

// 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

privKey := CkPrivateKey_Create();

// 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.
success := CkPrivateKey_LoadEncryptedPemFile(privKey,'qa_data/pem/rsa_passwd.pem','passwd');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(privKey));
    Exit;
  end;

jwt := CkJwt_Create();

// Build the JOSE header
jose := CkJsonObject_Create();
// Use RS256.  Pass the string "RS384" or "RS512" to use RSA with SHA-384 or SHA-512.
success := CkJsonObject_AppendString(jose,'alg','RS256');
success := CkJsonObject_AppendString(jose,'typ','JWT');
success := CkJsonObject_AppendString(jose,'kid','test-device');

// Now build the JWT claims (also known as the payload)
claims := CkJsonObject_Create();
success := CkJsonObject_AppendString(claims,'iss','9646844092');
success := CkJsonObject_AppendString(claims,'sub','test-device');
success := CkJsonObject_AppendString(claims,'aud','https://proda.humanservices.gov.au');

// Set the timestamp of when the JWT was created to now.
curDateTime := CkJwt_GenNumericDate(jwt,0);
success := CkJsonObject_AddIntAt(claims,-1,'iat',curDateTime);

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

// Produce the smallest possible JWT:
CkJwt_putAutoCompact(jwt,True);

// Create the JWT token.  This is where the RSA signature is created.
jwtToken := CkJwt__createJwtPk(jwt,CkJsonObject__emit(jose),CkJsonObject__emit(claims),privKey);

// ---------------------------------------------------------------------
// 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

http := CkHttp_Create();

req := CkHttpRequest_Create();
CkHttpRequest_putHttpVerb(req,'POST');
CkHttpRequest_putContentType(req,'application/x-www-form-urlencoded');

// Add the request params.
CkHttpRequest_AddParam(req,'grant_type','urn:ietf:params:oauth:grant-type:jwt-bearer');
CkHttpRequest_AddParam(req,'assertion',jwtToken);
CkHttpRequest_AddParam(req,'client_id','VendorClient03');

resp := CkHttpResponse_Create();
success := CkHttp_HttpReq(http,'https://vnd.proda.humanservices.gov.au/mga/sps/oauth/oauth20/token',req,resp);
if (success = False) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

Memo1.Lines.Add('Response status code = ' + IntToStr(CkHttpResponse_getStatusCode(resp)));
Memo1.Lines.Add('Response body:');
Memo1.Lines.Add(CkHttpResponse__bodyStr(resp));

CkPrivateKey_Dispose(privKey);
CkJwt_Dispose(jwt);
CkJsonObject_Dispose(jose);
CkJsonObject_Dispose(claims);
CkHttp_Dispose(http);
CkHttpRequest_Dispose(req);
CkHttpResponse_Dispose(resp);

end;