node-minecraft-protocol/examples/proxy/proxy.js

const mc = require('minecraft-protocol');

const states = mc.states;
function printHelpAndExit(exitCode) {
  console.log("usage: node proxy.js [<options>...] <target_srv> <version>");
  console.log("options:");
  console.log("  --dump name");
  console.log("    print to stdout messages with the specified name.");
  console.log("  --dump-all");
  console.log("    print to stdout all messages, except those specified with -x.");
  console.log("  -x name");
  console.log("    do not print messages with this name.");
  console.log("  name");
  console.log("    a packet name as defined in protocol.json");
  console.log("examples:");
  console.log("  node proxy.js --dump-all -x keep_alive -x update_time -x entity_velocity -x rel_entity_move -x entity_look -x entity_move_look -x entity_teleport -x entity_head_rotation -x position localhost 1.8");
  console.log("    print all messages except for some of the most prolific.");
  console.log("  node examples/proxy.js --dump open_window --dump close_window --dump set_slot --dump window_items --dump craft_progress_bar --dump transaction --dump close_window --dump window_click --dump set_creative_slot --dump enchant_item localhost 1.8");
  console.log("    print messages relating to inventory management.");

  process.exit(exitCode);
}

if(process.argv.length < 4) {
  console.log("Too few arguments!");
  printHelpAndExit(1);
}

process.argv.forEach(function(val) {
  if(val === "-h") {
    printHelpAndExit(0);
  }
});

const args = process.argv.slice(2);
let host;
let port = 25565;
let version;

let printAllNames = false;
const printNameWhitelist = {};
const printNameBlacklist = {};
(function() {
  for(let i = 0; i < args.length; i++) {
    const option = args[i];
    if(!/^-/.test(option)) break;
    if(option === "--dump-all") {
      printAllNames = true;
      continue;
    }
    i++;
    const name = args[i];
    if(option === "--dump") {
      printNameWhitelist[name] = "io";
    } else if(option === "-x") {
      printNameBlacklist[name] = "io";
    } else {
      printHelpAndExit(1);
    }
  }
  if(!(i + 2 <= args.length && args.length <= i + 4)) printHelpAndExit(1);
  host = args[i++];
  version = args[i++];
})();

if(host.indexOf(':') !== -1) {
  port = host.substring(host.indexOf(':') + 1);
  host = host.substring(0, host.indexOf(':'));
}

const srv = mc.createServer({
  'online-mode': false,
  port: 25566,
  keepAlive: false,
  version:version
});
srv.on('login', function(client) {
  const addr = client.socket.remoteAddress;
  console.log('Incoming connection', '(' + addr + ')');
  let endedClient = false;
  let endedTargetClient = false;
  client.on('end', function() {
    endedClient = true;
    console.log('Connection closed by client', '(' + addr + ')');
    if(!endedTargetClient)
      targetClient.end("End");
  });
  client.on('error', function(err) {
    endedClient = true;
    console.log('Connection error by client', '(' + addr + ')');
    console.log(err.stack);
    if(!endedTargetClient)
      targetClient.end("Error");
  });
  const targetClient = mc.createClient({
    host: host,
    port: port,
    username: client.username,
    keepAlive:false,
    version:version
  });
  client.on('packet', function(data, meta) {
    if(targetClient.state === states.PLAY && meta.state === states.PLAY) {
      if(shouldDump(meta.name, "o")) {
        console.log("client->server:",
          client.state + " "+ meta.name + " :",
          JSON.stringify(data));
      }
      if(!endedTargetClient)
        targetClient.write(meta.name, data);
    }
  });
  targetClient.on('packet', function(data, meta) {
    if(meta.state === states.PLAY && client.state === states.PLAY) {
      if(shouldDump(meta.name, "i")) {
        console.log("client<-server:",
          targetClient.state + "." + meta.name + " :" +
          JSON.stringify(data));
      }
      if(!endedClient) {
        client.write(meta.name, data);
        if(meta.name === 'set_compression'){
          client.compressionThreshold = data.threshold;
        } // Set compression
      }
    }
  });
  const bufferEqual = require('buffer-equal');
  targetClient.on('raw', function(buffer, meta) {
    if(client.state !== states.PLAY || meta.state !== states.PLAY)
      return;
    const packetData = targetClient.deserializer.parsePacketBuffer(buffer).data.params;
    const packetBuff = client.serializer.createPacketBuffer({name:meta.name, params:packetData});
    if(!bufferEqual(buffer, packetBuff)) {
      console.log("client<-server: Error in packet " + meta.state + "." + meta.name);
      console.log("received buffer",buffer.toString('hex'));
      console.log("produced buffer",packetBuff.toString('hex'));
      console.log("received length",buffer.length);
      console.log("produced length",packetBuff.length);
    }
    /*if (client.state === states.PLAY && brokenPackets.indexOf(packetId.value) !=== -1)
     {
     console.log(`client<-server: raw packet);
     console.log(packetData);
     if (!endedClient)
     client.writeRaw(buffer);
     }*/
  });
  client.on('raw', function(buffer, meta) {
    if(meta.state !== states.PLAY || targetClient.state !== states.PLAY)
      return;
    const packetData = client.deserializer.parsePacketBuffer(buffer).data.params;
    const packetBuff = targetClient.serializer.createPacketBuffer({name:meta.name, params:packetData});
    if(!bufferEqual(buffer, packetBuff)) {
      console.log("client->server: Error in packet " + meta.state + "." + meta.name);
      console.log("received buffer",buffer.toString('hex'));
      console.log("produced buffer",packetBuff.toString('hex'));
      console.log("received length",buffer.length);
      console.log("produced length",packetBuff.length);
    }
  });
  targetClient.on('end', function() {
    endedTargetClient = true;
    console.log('Connection closed by server', '(' + addr + ')');
    if(!endedClient)
      client.end("End");
  });
  targetClient.on('error', function(err) {
    endedTargetClient = true;
    console.log('Connection error by server', '(' + addr + ') ',err);
    console.log(err.stack);
    if(!endedClient)
      client.end("Error");
  });
});

function shouldDump(name, direction) {
  if(matches(printNameBlacklist[name])) return false;
  if(printAllNames) return true;
  return matches(printNameWhitelist[name]);

  function matches(result) {
    return result !== null && result.indexOf(direction) !== -1;
  }
}