Delphi ActiveX

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 ActiveX

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
privKey: TPrivateKey;
jwt: TChilkatJwt;
jose: TChilkatJsonObject;
claims: TChilkatJsonObject;
curDateTime: Integer;
jwtToken: WideString;
http: TChilkatHttp;
req: TChilkatHttpRequest;
resp: TChilkatHttpResponse;

begin
success := 0;

// 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 := TPrivateKey.Create(Self);

// 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 := privKey.LoadEncryptedPemFile('qa_data/pem/rsa_passwd.pem','passwd');
if (success = 0) then
  begin
    Memo1.Lines.Add(privKey.LastErrorText);
    Exit;
  end;

jwt := TChilkatJwt.Create(Self);

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

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

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

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

// Produce the smallest possible JWT:
jwt.AutoCompact := 1;

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

// ---------------------------------------------------------------------
// 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 := TChilkatHttp.Create(Self);

req := TChilkatHttpRequest.Create(Self);
req.HttpVerb := 'POST';
req.ContentType := 'application/x-www-form-urlencoded';

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

resp := TChilkatHttpResponse.Create(Self);
success := http.HttpReq('https://vnd.proda.humanservices.gov.au/mga/sps/oauth/oauth20/token',req.ControlInterface,resp.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Response status code = ' + IntToStr(resp.StatusCode));
Memo1.Lines.Add('Response body:');
Memo1.Lines.Add(resp.BodyStr);
end;