Net-request-response NPM

Net-Request-Response

It is a node module implements request-response model with for net.socket to make communication quicker and easier. It uses a custom protocol.

How to install

npm install net-request-response

Quick Start

var nrr = require('../index');

//server

var server = nrr.createServer();

server.on('clientConnected', function (client) {
	client.on('onRequest', function (payload, response){
    	console.log('Message from client: '+payload.toString());
    	//response
    	response('Okay, I am server.');
	});
});

server.listen(8080);

//client

var client =new nrr.Client();

client.connect(8080);

client.on('connect', function () {

	//send a string or buffer
	this.send('Hello, I am client.', function (error, responsePayload){
    	if (error) {
        	console.log(error);
        	return;
    	}
    	console.log('Response from server: '+responsePayload.toString());
	});
})

API

Net-Request-Reponse Methods

createServer(options)

options see nodejs document net.createServer.
callback is not supported, use clientConnected event instead.

createClient(options)

options see nodejs document net.createConnection.
callback is not supported, use connect event instead.

Client

new nrr.Client() can also be used to create a new client and then you can invoke client.connect() to connect lately

Server Events

server will emit some events about the state of qtpServer

'ready'

server will emit ready event once the server is listening correctly

server.on('ready',function(){ console.log(this.address()) });

'clientConnected'

server will emit clientConnected event if a client is connected to this server. A client object will be passed as an argument

server.on('clientConnected',function(client){

//handler client here });

'error'

server will emit error event when an error was caught. An error object will be passed as an argument

'close'

Fired when server is closed and stopped from listening

Server Methods

listen(options)

options see nodejs document net.Server.listen. Callback is not supported, use 'ready' event instead.

close()

See nodejs document net.Server.close.

address()

Return an address object

Client Events

client will emit some events when a request or response was handled ####'onRequest' client will emit onRequest event when it receives request from another side of socket with arguments payload and reponse:

payload. Buffer.
response. A function to call if you want to response this request.

client.on('onRequest',function(payload,response){
	console.log(payload);
	//response with a buffer or string
	response('message received');
});

'data'

raw tcp data will be passed to data event

client.on('data',function(data){
	//raw tcp data, including header

console.log(data); });

'error'

client will emit error event when an error was caught. An error object will be passed as an argument

'close'

fired when client is closed

Client Methods

send(payload,onResponse)

A request can be sent either on server side or client side

payload. Buffer or String to be sent.
onResponse. Function, it get invoked with arguments error and payload if a response is received.

client.send('Hello',function(error,payload){
	//get response
	if(error){
		console.log(error);
		return;
	}
		
	//payload is buffer
	console.log(payload);
});

close()

Message Format

type: qtp use the first 1 bit to mark request and response: 0 for request and 1 for response
sequenceNumber: the next 15 bits is sequenceNumber which is used to distinguish different messages, it is automatically increased by 1 everytime and it will be reset to 0 if it reaches 32768
remainingLength: It stands for the length of message body and it is extendible. The first 1 bit of every byte is to mark the end of header (when the bit is 0)
```
`00000101`           means length 5
`10000001 00000010`  means length 129   (1*2^7 + 2)
```
payload: Message body