Naive redis GET/SET server for Node.js. Version 2, no dependencies

redis_test2.js

'use strict';
var net = require('net');

var db = Object.create(null);
net.createServer(function(socket) {
  function sendError(err) {
    console.error(err);
    socket.write("-ERR " + err + "\r\n")
  }

  function execute(cmdArgs) {
    var name = cmdArgs[0];
    var first = cmdArgs[1];

    if (name === 'GET') {
      if (cmdArgs.length < 1) {
        sendError("GET expects 1 argument");
        return;
      }

      socket.write('$' + db[first].length + '\r\n' + first + '\r\n');
    }
    else if (name === 'SET') {
      if (cmdArgs.length < 2) {
        sendError("SET expects 2 arguments");
        return;
      }

      db[first] = cmdArgs[1];
      socket.write('+OK\r\n');
    }
    else {
      sendError("Unknown command: #" + name + "#");
    }
  }

  var waitForCmd = false;
  var argc = 0;
  var args = [];
  var offset = 0;

  function processLine(line) {
    if (waitForCmd) {
      waitForCmd = false;
      args.push(line);
      argc -= 1;
      if (argc === 0) {
        execute(args);
        args = [];
      }
      return;
    }
    if (!line) return;
    if (line.charAt(0) === '*') {
      argc = parseInt(line.substr(1));
      return;
    }

    else if (argc > 0 && line.charAt(0) === '$') {
      waitForCmd = true;
    }
    else {
      sendError('Unexpected operation "' + line + '"')
    }
  }

  socket.on('readable', function() {
    var buf = socket.read();
    if (!buf) return;
    for (; offset < buf.length; offset++) {
      if (buf[offset] === 0x0d) {
        processLine(buf.slice(0, offset).toString());
        buf = buf.slice(offset + 2); // account for \r\n
        offset = 0;
        socket.unshift(buf);
        return;
      }
    }
    socket.unshift(buf);
  });

  socket.on('error', function(e) { console.log(e) });
}).listen(6379);