xxp v0.1.7

CrissCross Protocol (xxp)

This module is for the xxp definition, containing a node module for encoding and decoding packets. This system is painfully simple and doesn't stream-read packets except for over the TCP network buffer stream. A packet will come through as an object to the receiver, not as a stream of data.

A future update could add this stream feature but CrissCross does not need it at the moment

Who this is for

This is for CrissCross apps to share a common protocol spec, though feel free to use this protocol method for anything you'd like.

This API isn't stable for other projects. That's why this isn't in the npm registry.

Fork to use stabily and modify as you want

Handlers

A handler system needs to be built separately to work with different message types. In the following examples, a handler already exists that uses the "type" header in the packet.

Usage examples

Assuming an output stream to another server and that the module is loaded:

Send a random number to a remote server as a reply

const num = Math.floor(Math.random() * (Number.MAX_SAFE_INTEGER - 1));

const packet = packetFactory.newPacket({
  header: {
    type: "network_reply_generic",
    "xxp__responseto": header["xxp__packetid"]
  },
  content: {
    number: num
  }
}).packet;

stream.write(packet);

Listen to messages as a server

In this example, the messageHandler argument passed to the packetDecoder is a function that accepts the arguments ({ header, content, stream }).

server = net.createServer(socket => {
  // This lets the server handle incoming messages with the message handlers
  packetDecoder(socket, messageHandler);

  socket.on("end", () => {
    // Lost connection, looks intentional (FIN packet sent)
    // We should have received a goodbye message so this shouldn't be an issue
  });

  socket.on("ready", () => {
    // Store reference to socket
    const address = socket.address();
    activeSockets[address.address] = socket;
  });
});

server.on("error", err => {
  throw err;
});

server.listen(port, () => {
  console.log(`Server bound to ${port}`);
});