smp

Streaming Message Protocol for Node.js

Streaming Message Protocol for Node.js.

The Streaming Message Protocol (SMP) is a lightweight and efficient data framing protocol for exchanging messages across network transports like: TCP, TLS, WebSocket.

To read the Streaming Message Protocol Specification.

SMP is a binary protocol allowing any binary data format to be used. You can of cause use non binary data such as text or JSON - by converting to a buffer. You can also encode multiple arguments within a single message, for example: binary from a photo and JSON about that photo, as separate arguments. This means you don't have to use serialization to combine binary and text based data together into a single argument - although you could if you want.

SMP solves three data scenarios when sending messages across a network:

1. A whole small message.
2. A whole large message, called frames.
3. A never ending message, also frames.

SMP makes frames of large or never ending messages efficiently sized to best fit over the network, frames are assigned a unique ID and order number. This approach allows asynchronously sent frames - you could even send frames to different receivers, to be reassembled later.

SMP-Protocol-Version: 1.1.

TODO: fix and finsih frames support.

Installation

npm install smp

Examples

See examples folder. To print use preview, eg: node examples/message.js --preview

var smp = require('smp');
 
var framed = smp.encode([new Buffer('hello world')]);
console.log('framed', framed);    // <Buffer 01 00 0b 68 65 6c 6c 6f 20 77 6f 72 6c 64>
 
var message = smp.decode(framed.toBuffer());
console.log('message', message);
 
var payload = message.args[0].toString();
console.log('payload:', payload);
 

Stream through TCP.

var net = require('net');    // TCP
var smp = require('smp');
 
var server = net.createServer(function(sock){
 
  var stream = smp.StreamParser;
  var parser = new stream();
 
  // can use parser.on( 'frame', 'message', 'err', 'errorMessage', 'information', etc.
 
  parser.on('frame', function(frame){
    console.log('frame', frame);
  });
 
  sock.pipe(parser);
  
});
 
server.listen(8888);
 
var client = net.connect(8888);
client.write(smp.encode([new Buffer('abcdefghijklmnopqrstuvwxyz'), new Buffer('0123456789')], {max_message_size: 10, id: 555, first: true}).toBuffer());
 

Using WebSockets, npm install naked-websocket.

var nws = require('naked-websocket');
var smp = require('smp');
 
var server = nws.createServer({protocol: 'ws'}, function(socket) {
 
  var stream = smp.StreamParser;
  var parser = new stream();
 
  // can use parser.on( 'frame', 'message', 'information', etc.
 
  parser.on('message', function(message){
    console.log('message', message);
    console.log('payload', message.args[0].toString());
  });
 
  socket.pipe(parser);
  
}).listen(8888);
 
 
var options = {
  protocol: 'ws',
  hostname: '127.0.0.1',
  port: 8888
};
 
var client = nws.connect(options, function(socket) {
 
  socket.write(smp.encode([new Buffer('hello world')]).toBuffer());
  
});
 

SMP Meta Codes

SMP uses meta codes within each message/frame to define meaning between the sender and receiver.

To read the Streaming Message Protocol Specification.

+------+-------------------+-----------------------------------------------------------------------+
| FLAG | DESCRIPTION       | NOTES                                                                 |
+------+-------------------+-----------------------------------------------------------------------+
|    0 | WHOLE MESSAGE     | Payload data, a whole complete MESSAGE, when ARGUMENTS PAYLOAD size < | 
|      |                   | MAX-MESSAGE-SIZE.                                                     |
+------+-------------------+-----------------------------------------------------------------------+
|    1 | NEW FRAME         | Payload data, a new FRAME.                                            |
+------+-------------------+-----------------------------------------------------------------------+
|    2 | CONTINUING FRAME  | Payload data, a middle FRAME.                                         |
+------+-------------------+-----------------------------------------------------------------------+
|    3 | LAST FRAME        | Payload data, the last FRAME.                                         |
+------+-------------------+-----------------------------------------------------------------------+
|    4 | INFOMATION        | Information, contained within the PAYLOAD.                            |
+------+-------------------+-----------------------------------------------------------------------+
|    5 | ERROR             | Error, first ARGUMENT is a error code (3.2.), second ARGUMENT is the  |
|      |                   | error message (3.2.).                                                 |
+------+-------------------+-----------------------------------------------------------------------+
|    6 | HEARTBEAT         | Heartbeat, with optional PAYLOAD data.                                |
+------+-------------------+-----------------------------------------------------------------------+
|    7 | STOP              | Action, stop sending or receiving payload data, will immediately      |
|      |                   | close any socket connection.                                          |
+------+-------------------+-----------------------------------------------------------------------+
|    8 | PAUSE             | Action, pause sending or receiving payload data.                      |
+------+-------------------+-----------------------------------------------------------------------+
|    9 | RESUME            | Action, resume sending or receiving payload data.                     |
+------+-------------------+-----------------------------------------------------------------------+
|   10 | CHECKPOINT        | Information, a list of sequence number(s) of committed objects.       |
+------+-------------------+-----------------------------------------------------------------------+
|   11 | NAMESPACE         | Namespace, a message type of any custom name.                         |
+------+-------------------+-----------------------------------------------------------------------+
|   12 | BLOCK             | Payload data wrapper, a list of payload data (as EG, CODE: 0,1,2,3).  |
+------+-------------------+-----------------------------------------------------------------------+
|   13 | ROW               | Payload data wrapper, a list of BLOCKs.                               |
+------+-------------------+-----------------------------------------------------------------------+
|   14 | SUPER             | Super Protocol, build a custom higher-level messaging protocol.       |
+------+-------------------+-----------------------------------------------------------------------+
|   15 | RESERVED          | Reserved for future versions.                                         |
+------+-------------------+-----------------------------------------------------------------------+

See /examples/infos.js for examples.

Options

Encode options.

 max_message_size: number,   // byte size of a whole message, if greater will be frames of (default: 1493).
               id: number,   // can set a ID for frames, from 0 to 65535.
            first: boolean,  // if true and frames, frame[0] will be first frame (CODE:1).
         complete: boolean,  // if true and frames, frame[frames.length] will be last frame (CODE:3).
          toFrame: boolean   // if true will be frame even when size less than max_message_size.

Extentions

The Streaming Message Protocol allows extentions. These are not defined by using first nibble flags, but some other method of identification such as file extention.

Benchmarking

See bm folder to run benchmarking tests.

Results

Using a WebSocket connection naked-websocket and sending 200 byte SMP messages, I get over 300,000 messages per second.

---------------------------------------------
| RESULTS ~
---------------------------------------------
|     median: 322,581 ops/s
|       mean: 275,587 ops/s
|      total: 2,750,084 ops in 9.979s
|    through: 55.39 MB/s
---------------------------------------------

Thanks

Thanks to TJ Holowaychuk for inspiration of multiple arguments within a message.

License

Choose either: MIT or Apache 2.0.