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Pascal (Lazarus/Delphi)

Create a JWS into a StringBuilder

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.CreateJwsSb, which creates a JWS and writes it into a StringBuilder.

Background. JWS (JSON Web Signature) integrity-protects a payload with a signature or MAC. The header alg names the algorithm; this example uses HMAC-SHA256 (HS256) with a symmetric MAC key.

Chilkat Pascal (Lazarus/Delphi) Downloads

Pascal (Lazarus/Delphi)
program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.StringBuilder,
  Chilkat.Jws,
  Chilkat.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  jws: TJws;
  header: TJsonObject;
  bIncludeBom: Boolean;
  base64Key: string;
  sbJws: TStringBuilder;

begin
  success := False;

  jws := TJws.Create;

  //  Set the protected header for signer 0, specifying the signature algorithm (alg).
  header := TJsonObject.Create;
  header.UpdateString('alg','HS256');
  success := jws.SetProtectedHeader(0,header);
  if (success = False) then
    begin
      WriteLn(jws.LastErrorText);
      Exit;
    end;

  //  Set the payload to be signed.
  bIncludeBom := False;
  success := jws.SetPayload('This is the content to sign.','utf-8',bIncludeBom);
  if (success = False) then
    begin
      WriteLn(jws.LastErrorText);
      Exit;
    end;

  //  Provide the HMAC key (base64) for signer 0.  In production, obtain the key from a secure source
  //  rather than hard-coding it.
  base64Key := 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
  success := jws.SetMacKey(0,base64Key,'base64');
  if (success = False) then
    begin
      WriteLn(jws.LastErrorText);
      Exit;
    end;

  //  Create the JWS and write it into a StringBuilder.
  sbJws := TStringBuilder.Create;
  success := jws.CreateJwsSb(sbJws);
  if (success = False) then
    begin
      WriteLn(jws.LastErrorText);
      Exit;
    end;
  WriteLn(sbJws.GetAsString());


  jws.Free;
  header.Free;
  sbJws.Free;

end;

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

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.