zmq-service-suite-message/message.js

0MQ Service oriented Suite Message module

var util = require('util'),
    msgpack = require('msgpack-js'),
    uuid = require('uuid'),
    PROTOCOL_VERSION = 'ZSS:0.0';

function setClient(msg) {
  var clientParts = !msg.identity ? [null, null] : msg.identity.split('#');
  msg.client = clientParts[0];
  msg.clientId = clientParts[1];
}

function setTransaction(msg) {
  var reqId = null;

  if (msg.headers) {
    var key = Object.keys(msg.headers).find(function(e){
      return e.toLowerCase() === 'x-request-id';
    });

    if (key) { reqId = msg.headers[key]; }
  }

  msg.transaction = reqId || null;
}

var Message = function(sid, verb, sversion, identity, headers){
  var self = this;

  if (!sversion){
    sversion = '*';
  }

  self.identity = identity || null;
  setClient(self);

  self.protocol = PROTOCOL_VERSION;
  self.type = Message.Type.REQ;
  self.rid = uuid.v1();
  self.address = {
    sid: sid,
    sversion: sversion,
    verb: verb
  };

  self.headers = headers || null;
  setTransaction(self);

  self.status = null;
  self.payload = null;

  self.toString = function(){
    var message = "********\nFRAME 0: %s\nFRAME 1: %s\nFRAME 2: %s\nFRAME 3: %s\nFRAME 4: %j\nFRAME 5: %j\nFRAME 6: %s\nFRAME 7: %j\n********";
    return util.format(message, self.identity, self.protocol, self.type, self.rid, self.address, self.headers, self.status, self.payload);
  };

  self.toFrames = function(){
    return Message.toFrames(self);
  };
};

Message.Type = {
  REQ: "REQ",
  REP: "REP"
};

Message.parse = function(frames, skipPayload){
  var msg = new Message();

  if(frames.length === 7) {
    frames.unshift('');
  }

  var identity = String(frames[0]);
  var status = parseInt(frames[6], 10);

  msg.identity = identity === '' ? null : identity;
  setClient(msg);

  msg.protocol = String(frames[1]);
  msg.type = String(frames[2]);
  msg.rid = String(frames[3]);
  msg.address = msgpack.decode(frames[4]);

  msg.headers = msgpack.decode(frames[5]);
  setTransaction(msg);

  msg.status = status ? status : null;

  // for performance reason is usefull to allow message parse
  // allow to parse the message without decode the payload
  msg.payload = (!skipPayload) ? msgpack.decode(frames[7]) : null;

  return msg;
};

Message.toFrames = function(msg){
  var frames = [
    msg.identity ? msg.identity : '',
    msg.protocol,
    msg.type,
    msg.rid,
    msgpack.encode(msg.address),
    msgpack.encode(msg.headers),
    msg.status,
    msgpack.encode(msg.payload)
  ];
  return frames;
};

module.exports = Message;