(Delphi DLL) Create JWT Using HS256, HS384, or HS512

Demonstrates how to create a JWT using HS256, HS384, or HS512. (HS256 is JWT's acronym for HMAC-SHA256.) When HMAC is used, the secret is a shared secret (i.e. password) that both client and server know beforehand.

This example also demonstrates how to include time constraints:

• nbf: Not Before Time
• exp: Expiration Time
• iat: Issue At Time

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
jwt: HCkJwt;
jose: HCkJsonObject;
success: Boolean;
claims: HCkJsonObject;
curDateTime: Integer;
strJwt: PWideChar;

begin
// Demonstrates how to create an HMAC JWT using a shared secret (password).

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

jwt := CkJwt_Create();

// Build the JOSE header
jose := CkJsonObject_Create();
// Use HS256.  Pass the string "HS384" or "HS512" to use a different algorithm.
success := CkJsonObject_AppendString(jose,'alg','HS256');
success := CkJsonObject_AppendString(jose,'typ','JWT');

// Now build the JWT claims (also known as the payload)
claims := CkJsonObject_Create();
success := CkJsonObject_AppendString(claims,'iss','http://example.org');
success := CkJsonObject_AppendString(claims,'sub','John');
success := CkJsonObject_AppendString(claims,'aud','http://example.com');

// 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 "not process before" timestamp to now.
success := CkJsonObject_AddIntAt(claims,-1,'nbf',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);

strJwt := CkJwt__createJwt(jwt,CkJsonObject__emit(jose),CkJsonObject__emit(claims),'secret');

Memo1.Lines.Add(strJwt);

CkJwt_Dispose(jwt);
CkJsonObject_Dispose(jose);
CkJsonObject_Dispose(claims);

end;