PayPal usando REST

[oesqueda]

Hola,

estoy tratando de hacer una aplicacion para pago con PayPal (en realidad es para android e iOS pero lo que pruebo funciona en ambos mundos).

Uso la REST API de paypal https://developer.paypal.com/webapps...oper/docs/api/

La cuestion es que si puedo obtener el TOKEN, es decir ya me valide el acceso.
Pero al hacer el pago (Payment) me devuelve la respuesta JSON en blanco, alguien puede ayudarme.

Adjunto codigo fuente.
En el codigo fuente no pongo client id y secreto, por cuestion de seguridad.
En esta lista esta el codigo fuete y el ejecutable:
www.itcmx.com/PayPalREST.rar

Por su valiosa ayuda mil gracias

Este es el codigo para el token

Código Delphi [-]
var
  slParameters:TStringList;
  Response:TStringStream;
  json, sTokenType:string;
  PayPalObj:TJSONObject;
  jTokenValue:TJSONValue;
begin
memLog.Lines.Clear;
memLog.Lines.Add('TOKEN');

btnPayment.Enabled := False;
http.Request.ContentType := 'application/x-www-form-urlencoded';
http.Request.Accept := 'application/json';
http.Request.AcceptLanguage := 'en_US';
http.Request.BasicAuthentication := True;

http.Request.Username := 'CLIENT ID';
http.Request.Password := 'SECRETA';

slParameters := TStringList.Create;
Response := TStringStream.Create;
try
  //get an access token
  slParameters.Add('grant_type=client_credentials');
  json := http.Post('https://api.sandbox.paypal.com/v1/oauth2/token', slParameters);
  //json := Response.DataString;
  PayPalObj := TJSONObject.ParseJSONValue(TEncoding.ASCII.GetBytes(json), 0) as TJSONObject;
  try
    jTokenValue := PayPalObj.Get('access_token').JsonValue;
    AccessToken := jTokenValue.Value;
    jTokenValue := PayPalObj.Get('token_type').JsonValue;
    sTokenType := jTokenValue.Value;

    Memo1.Lines.Clear;
    Memo1.Lines.Text := PayPalObj.ToString;
    Memo1.Lines.Add('Size: ' + IntToStr(PayPalObj.EstimatedByteSize));
  finally
    PayPalObj.Free;
  end;

  if sTokenType <> 'Bearer' then
    Exit;

  if AccessToken = '' then
    Exit;

  lblToken.Caption := Format('Token: %s - Type: %s', [AccessToken, sTokenType]);
  btnPayment.Enabled := True;
finally
  Response.Free;
  slParameters.Free;
end;

Y aqui el del payment

Código Delphi [-]
var
  PayPalObj :TJSONObject;
  PayPalObj2 :TJSONObject;
  RedirectObj :TJSONObject;
  PayerObj :TJSONObject;

  TransactionsArray : TJSONArray;
  AmountObj : TJSONObject;
  TransactionObj : TJSONObject;
  FundingArray : TJSONArray;
  CreditCardObj : TJSONObject;

  ssJson : TStringStream;
  json, Authorization:string;
begin
//create a payment
memLog.Lines.Add('PAYMENT');
PayPalObj := TJSONObject.Create;
try
  RedirectObj := TJSONObject.Create;
  try
    RedirectObj.AddPair(TJSONPair.Create('return_url', TJSONString.Create('http://blahblah.com/return')));
    RedirectObj.AddPair(TJSONPair.Create('cancel_url', TJSONString.Create('http://blahblah.com/cancel')));
  except
    RedirectObj.Free;
    Exit;
  end;

  PayerObj := TJSONObject.Create;
  try
    PayerObj.AddPair(TJSONPair.Create('payment_method', TJSONString.Create('credit_card')));

    CreditCardObj := TJSONObject.Create;
    CreditCardObj.AddPair('number', '5500005555555559');
    CreditCardObj.AddPair('type', 'mastercard');
    CreditCardObj.AddPair('expire_month', '12');
    CreditCardObj.AddPair('expire_year', '2018');
    CreditCardObj.AddPair('cvv2', '111');
    CreditCardObj.AddPair('first_name', 'yo');
    CreditCardObj.AddPair('last_name', 'tu');

    FundingArray := TJSONArray.Create;
    FundingArray.Add(CreditCardObj);

    PayerObj.AddPair(TJSONPair.Create('funding_instruments', FundingArray));
  except
    PayerObj.Free;
    Exit;
  end;

  TransactionsArray := TJSONArray.Create;
  AmountObj := TJSONObject.Create;
  TransactionObj := TJSONObject.Create;
  try
    AmountObj.AddPair('currency', TJSONString.Create('USD'));
    AmountObj.AddPair('total', TJSONString.Create('1'));
    TransactionObj.AddPair('amount', AmountObj);
    TransactionObj.AddPair('description', TJSONString.Create('payment description'));
    TransactionsArray.Add(TransactionObj);
  except
    TransactionsArray.Free;
    AmountObj.Free;
    TransactionObj.Free;
    Exit;
  end;

  PayPalObj.AddPair(TJSONPair.Create('intent', TJSONString.Create('sale')));
  PayPalObj.AddPair(TJSONPair.Create('payer', PayerObj));
  PayPalObj.AddPair(TJSONPair.Create('transactions', TransactionsArray));
  //PayPalObj.AddPair(TJSONPair.Create('redirect_urls', RedirectObj));

  Memo1.Lines.Add(' ');
  Memo1.Lines.Add(PayPalObj.ToString);
  Memo1.Lines.Add('Size: ' + IntToStr(PayPalObj.EstimatedByteSize));

  http.Request.Clear;
  http.Request.ContentType := 'application/json';
  http.Request.CustomHeaders.Clear;
  //http.Request.CustomHeaders.FoldLines := False;  //have tried this with no success
  Authorization := Format('Bearer %s', [AccessToken]);
  http.Request.CustomHeaders.AddValue('Authorization', Authorization);  //token obtained from first request

  Memo1.Lines.Add(' ');
  Memo1.Lines.Add(http.Request.CustomHeaders.Text);
  ssJson := TStringStream.Create(PayPalObj.ToString, TEncoding.ASCII);
  try
    { AQUI SE OBTIENE EL VALOR EN BLANCO }
    json := http.Post('https://api.sandbox.paypal.com/v1/payments/payment', ssJson);
    lblPayment.Caption := json;

    PayPalObj2 := TJSONObject.ParseJSONValue(TEncoding.ASCII.GetBytes(json), 0) as TJSONObject;
    if Assigned(PayPalObj2) then
      try
        Memo1.Lines.Add(' ');
        Memo1.Lines.Add(PayPalObj2.ToString);
      finally
        PayPalObj2.Free;
      end;
  finally
    ssJson.Free;
  end;
finally
  PayPalObj.Free;
end;