examples/consumer.cpp

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2023, Regents of the University of California
 *
 * NAC library is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * NAC library is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 *
 * You should have received copies of the GNU General Public License and GNU Lesser
 * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of NAC library authors and contributors.
 */

#include <ndn-cxx/face.hpp>
#include <ndn-cxx/security/validator-config.hpp>

// #include <ndn-nac/decryptor.hpp>
#include "decryptor.hpp"

#include <iostream>

// Enclosing code in ndn simplifies coding (can also use `using namespace ndn`)
namespace ndn {
namespace nac {
// Additional nested namespaces should be used to prevent/limit name conflicts
namespace examples {

class Consumer
{
public:
  Consumer()
    : m_decryptor(m_keyChain.getPib().getDefaultIdentity().getDefaultKey(),
                  m_validator, m_keyChain, m_face)
  {
    m_validator.load(R"CONF(
        trust-anchor
        {
          type any
        }
      )CONF", "fake-config");
  }

  void
  run()
  {
    using namespace std::placeholders;

    Interest interest(Name("/example/testApp/randomData"));
    interest.setCanBePrefix(true);
    interest.setMustBeFresh(true);
    interest.setInterestLifetime(3_s); // 3 seconds

    std::cout << "Sending Interest " << interest << std::endl;
    m_face.expressInterest(interest,
                           std::bind(&Consumer::onData, this,  _1, _2),
                           std::bind(&Consumer::onNack, this, _1, _2),
                           std::bind(&Consumer::onTimeout, this, _1));

    // processEvents will block until the requested data is received or a timeout occurs
    m_face.processEvents();
  }

private:
  void
  onData(const Interest&, const Data& data)
  {
    m_validator.validate(data,
      [=] (const Data& data) {
        m_decryptor.decrypt(data.getContent().blockFromValue(),
          [] (const ConstBufferPtr& content) {
            std::cout << "Decrypted content: "
                      << std::string(reinterpret_cast<const char*>(content->data()), content->size())
                      << std::endl;
          },
          [] (const ErrorCode&, const std::string& error) {
            std::cerr << "Cannot decrypt data: " << error << std::endl;
          });
      },
      [] (const Data&, const ValidationError& error) {
        std::cerr << "Cannot validate retrieved data: " << error << std::endl;
      });
  }

  void
  onNack(const Interest& interest, const lp::Nack& nack) const
  {
    std::cout << "Received Nack with reason " << nack.getReason()
              << " for interest " << interest << std::endl;
  }

  void
  onTimeout(const Interest& interest) const
  {
    std::cout << "Timeout for " << interest << std::endl;
  }

private:
  KeyChain m_keyChain;
  Face m_face{nullptr, m_keyChain};
  ValidatorConfig m_validator{m_face};
  Decryptor m_decryptor;
};

} // namespace examples
} // namespace nac
} // namespace ndn

int
main(int argc, char** argv)
{
  try {
    ndn::nac::examples::Consumer consumer;
    consumer.run();
    return 0;
  }
  catch (const std::exception& e) {
    std::cerr << "ERROR: " << e.what() << std::endl;
    return 1;
  }
}