Pascal (Lazarus/Delphi)

Xero 2 Legged OAuth for Private Application

This example demonstrates the REST object for 2-legged OAuth for a private application.

An application can setup OAuth1 for a given instance of the Chilkat REST object, and then use the instance for many REST API calls. This example demonstrates the OAuth1 setup and initial connection. This code would typically be placed in a subroutine/function to "initalize" the REST object before beginning to use it for REST HTTP requests.

Note: Xero private applications use 2 legged OAuth and bypass the user authorization workflow in the standard OAuth process. Private applications are linked to a single Xero organisation which is chosen when you register your application. In summary: 2-legged OAuth1 is for applications that access the data that they themselves own.

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.Pfx,
  Chilkat.OAuth1,
  Chilkat.Rest,
  Chilkat.PrivateKey;

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

procedure RunDemo;
var
  success: Boolean;
  rest: TRest;
  consumerKey: string;
  consumerSecret: string;
  pfx: TPfx;
  privKeyFromPfx: TPrivateKey;
  privKeyFromPem: TPrivateKey;
  oauth1: TOAuth1;
  bAutoReconnect: Boolean;

begin
  success := False;

  //  This sample code would typically be placed in a subroutine or function
  //  where the rest object is passed by reference.
  //  It does the OAuth1 setup and makes the initial connection.
  rest := TRest.Create;

  consumerKey := 'XERO_PRIVATE_APP_KEY';
  consumerSecret := 'XERO_PRIVATE_APP_SECRET';

  //  Let's get our private key from our PFX (password protected), or the PEM (unprotected).
  //  You can decide which to use.  Either is OK, although I would recommend keeping your
  //  private keys in a PFX and not in an unprotected PEM.
  pfx := TPfx.Create;
  success := pfx.LoadPfxFile('qa_data/certs/xero_private_app/public_privatekey.pfx','PFX_PASSWORD');
  if (success = False) then
    begin
      WriteLn(pfx.LastErrorText);
      Exit;
    end;

  privKeyFromPfx := TPrivateKey.Create;
  success := pfx.PrivateKeyAt(0,privKeyFromPfx);
  if (success = False) then
    begin
      WriteLn(pfx.LastErrorText);
      Exit;
    end;

  //  Or we can load from a PEM..
  privKeyFromPem := TPrivateKey.Create;
  success := privKeyFromPem.LoadPemFile('qa_data/certs/xero_private_app/privatekey.pem');
  if (success = False) then
    begin
      WriteLn(privKeyFromPem.LastErrorText);
      Exit;
    end;

  //  Note: There are many other means for loading a private key, including
  //  from other formats and directly from memory (i.e. not file-based).

  oauth1 := TOAuth1.Create;
  oauth1.ConsumerKey := consumerKey;
  oauth1.ConsumerSecret := consumerSecret;
  oauth1.Token := consumerKey;
  oauth1.TokenSecret := consumerSecret;
  oauth1.SignatureMethod := 'RSA-SHA1';
  oauth1.SetRsaKey(privKeyFromPfx);

  //  Make the initial connection.
  //  A single REST object, once connected, can be used for many Xero REST API calls.
  //  The auto-reconnect indicates that if the already-established HTTPS connection is closed,
  //  then it will be automatically re-established as needed.
  bAutoReconnect := True;
  success := rest.Connect('api.xero.com',443,True,bAutoReconnect);
  if (success = False) then
    begin
      WriteLn(rest.LastErrorText);
      Exit;
    end;

  //  Finally, install the OAuth1 authenticator.
  //  (It make no difference whether this happens before or after the
  //  connection is established.)
  rest.SetAuthOAuth1(oauth1,False);

  WriteLn('OK, the Xero OAuth1 is initialized and the REST object is ready to make REST API calls..');


  rest.Free;
  pfx.Free;
  privKeyFromPfx.Free;
  privKeyFromPem.Free;
  oauth1.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.