Pascal (Lazarus/Delphi)

Walmart Partner API Authentication (Generate a Signature for a Request)

See more RSA Examples

Demonstrates how to generate a signature for a Walmart Partner REST API call. 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.PrivateKey,
  Chilkat.Rsa,
  Chilkat.CkDateTime;

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

procedure RunDemo;
var
  success: Boolean;
  consumerId: string;
  baseUrl: string;
  privateEncodedStr: string;
  httpMethod: string;
  dt: TCkDateTime;
  bLocal: Boolean;
  timeStampVal: Integer;
  sbStringToSign: TStringBuilder;
  privKey: TPrivateKey;
  rsa: TRsa;
  signatureString: string;

begin
  success := False;

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

  consumerId := 'b68d2a72....';
  baseUrl := 'https://marketplace.walmartapis.com/v2/feeds';
  //  This is your Base64 encoded private key
  privateEncodedStr := 'MIICeAIBADANBgkqhkiG9w0BAQEFAA......';
  httpMethod := 'GET';

  //  We need a timestamp in decimal string form representing the number of milliseconds since Jan 01 1970 UTC.
  dt := TCkDateTime.Create;
  //  Set bLocal = True for a timestamp in the local timezone.  Set bLocal = False for a UTC timestamp.
  bLocal := False;
  //  This gets the timestamp in seconds, not milliseconds.
  timeStampVal := dt.GetAsUnixTime(bLocal);

  //  Build the string to sign.
  sbStringToSign := TStringBuilder.Create;
  sbStringToSign.Append(consumerId);
  sbStringToSign.Append(#10);
  sbStringToSign.Append(baseUrl);
  sbStringToSign.Append(#10);
  sbStringToSign.Append(httpMethod);
  sbStringToSign.Append(#10);
  sbStringToSign.AppendInt(timeStampVal);
  //  We add three zero's so that the timestamp value is in milliseconds.
  //  We don't care about accuracy down to less than a second.
  //  All the server cares about is that the request was signed at the current date/time
  //  within some reasonable margin of error (to account for systems having clocks
  //  that may be slightly different).
  sbStringToSign.Append('000' + #10);

  privKey := TPrivateKey.Create;
  //  Load the private key into a private key object.
  //  Note: Technically the private key is not PEM because it lacks the header/footer strings
  //  used for PEM.  However, the LoadPem method will still accept it and load it correctly.
  success := privKey.LoadPem(privateEncodedStr);
  if (success = False) then
    begin
      WriteLn(privKey.LastErrorText);
      Exit;
    end;

  rsa := TRsa.Create;
  success := rsa.UsePrivateKey(privKey);
  if (success = False) then
    begin
      WriteLn(rsa.LastErrorText);
      Exit;
    end;

  //  We want a base64 signature string.
  rsa.EncodingMode := 'base64';

  signatureString := rsa.SignStringENC(sbStringToSign.GetAsString(),'SHA256');
  if (rsa.LastMethodSuccess = False) then
    begin
      WriteLn(rsa.LastErrorText);
      Exit;
    end;

  WriteLn('Signature String: ' + signatureString);


  dt.Free;
  sbStringToSign.Free;
  privKey.Free;
  rsa.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.