No, you're not missing anything and yes, you do need to add some form of termination to your messages.

There are two basic problems here:

1. The TCP protocol is stream-oriented, not message-oriented; it has no intrinsic knowledge of what might constitute a message.




2. The data event fired by the node.js net library indicates that some data has arrived but without any idea of what a message might contain, it cannot indicate that it has received any specific data.

So by sending your messages faster than Node can process them, the socket recv buffer fills with multiple messages.

A typical solution to this problem is to add line-termination, as can be found in
https://github.com/baudehlo/Haraka/blob/master/connection.js at lines 32-34:

self.client.on('data', function (data) {

    self.process_data(data);

});

and lines 110-134:

Connection.prototype.process_data = function (data) {

  if (this.disconnected) {

    logger.logwarn(data after disconnect from  + this.remote_ip);

    return;

  }



  this.current_data += data;

  this._process_data();

};



Connection.prototype._process_data = function() {

  var results;

  while (results = line_regexp.exec(this.current_data)) {

    var this_line = results[1];

    if (this.state === 'pause') {

        this.early_talker = 1;

        var self = this;

        // If you talk early, we're going to give you a delay

        setTimeout(function() { self._process_data() }, this.early_talker_delay);

        break;

    }

    this.current_data = this.current_data.slice(this_line.length);

    this.process_line(this_line);

  }

};