Vix.cpp

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P2P Node ​

This example shows how to start a minimal P2P node using the vix::p2p module.

What you get:

  • TCP node (inbound + outbound)
  • UDP discovery (LAN broadcast or multicast)
  • Optional HTTP bootstrap (registry pull, optional announce)
  • Secure handshake wiring (dev crypto by default)
  • Ping/Pong heartbeats and stale peer cleanup

Requirements ​

  • C++20
  • Vix.cpp installed
  • modules/p2p enabled

Minimal Example ​

Create p2p_node.cpp:

cpp
#include <vix/p2p/P2P.hpp>
#include <vix/p2p/Node.hpp>
#include <vix/p2p/Discovery.hpp>
#include <vix/p2p/Bootstrap.hpp>
#include <vix/p2p/Router.hpp>
#include <vix/p2p/Crypto.hpp>

#include <iostream>
#include <memory>
#include <string>

static void log_line(std::string_view s)
{
  std::cerr << s << "\n";
}

int main(int argc, char** argv)
{
  using namespace vix::p2p;

  std::string nodeId = "node-A";
  std::uint16_t listenPort = 9001;
  std::string bootstrapUrl;

  if (argc >= 2) nodeId = argv[1];
  if (argc >= 3) listenPort = static_cast<std::uint16_t>(std::stoi(argv[2]));
  if (argc >= 4) bootstrapUrl = argv[3];

  NodeConfig cfg;
  cfg.node_id = nodeId;
  cfg.listen_port = listenPort;
  cfg.max_peers = 64;
  cfg.handshake_timeout_ms = 3000;
  cfg.on_log = log_line;

  auto node = make_tcp_node(std::move(cfg));
  node->set_router(std::make_shared<MemoryRouter>());
  node->set_crypto(std::make_shared<NullCrypto>());

  if (!bootstrapUrl.empty())
  {
    BootstrapConfig bcfg;
    bcfg.self_node_id = nodeId;
    bcfg.self_tcp_port = listenPort;
    bcfg.registry_url = bootstrapUrl;
    bcfg.mode = BootstrapMode::PullAndAnnounce;

    node->set_bootstrap(make_http_bootstrap(std::move(bcfg), nullptr));
  }

  auto runtime = std::make_shared<P2PRuntime>(node);
  runtime->start();

  std::cerr << "[p2p] started node_id=" << nodeId
            << " listen=" << listenPort << "\n";

  runtime->wait();
  return 0;
}

Run ​

Local LAN test ​

Terminal 1:

bash
vix run p2p_node.cpp -- node-A 9001

Terminal 2:

bash
vix run p2p_node.cpp -- node-B 9002

Nodes discover each other via UDP broadcast.

With HTTP bootstrap registry ​

If a registry is running on port 8089:

bash
vix run p2p_node.cpp -- node-A 9001 http://127.0.0.1:8089
vix run p2p_node.cpp -- node-B 9002 http://127.0.0.1:8089

Notes ​

  • Default crypto is NullCrypto (development only).
  • Transport is TCP.
  • Ping/Pong is automatic.
  • For production, replace crypto with a secure implementation.