request-stream

Request-Stream

Request-Stream allows you to send a JSON request and wait for a JSON reply over a stream

npm install request-stream

Summary

Request-Stream makes it easy to implement request-response services over streams.

To listen and reply to requests you just need to listen to the request event

var r = rs();

fromStream.pipe(r).pipe(fromStream);

r.on('request', function(request, respond) {
	respond(null, request[0]+request[1]); // send a reply back to the requester
});

To send requests and wait for replies you call r.request(message, callback)

var rs = require('request-stream');
var r = rs();

toStream.pipe(r).pipe(toStream);

r.request([1,2], function(err, reply) {
	console.log(err, reply); // prints 3
});

r.request([2,3], function(err, reply) {
	console.log(err, reply); // prints 5
});

If you don't care about replying to requests you should probably use something like emit-stream instead

Example

Lets try to setup a simple server

var rs = require('request-stream');
var net = require('net');

net.createServer(function(socket) {
	var r = rs();

	socket.pipe(r).pipe(socket);

	r.on('request', function(request, respond) {
		r.request({server:request}, respond);
	});
}).listen(9000);

To make a request to the server we need to create a socket to the server and pipe our request to that.

var socket = net.connect(9000);
var r = rs();

socket.pipe(r).pipe(socket);

r.on('request', function(request, respond) {
	respond(null, {client:request});
});

r.request('echo me please', function(err, reply) {
	console.log(err, reply);  // prints {client:{server:'echo me please'}}
});
r.request('echo me please again', function(err, reply) {
	console.log(err, reply); // prints {client:{server:'echo me please again'}}
});

If we wanted to use tls instead of tcp we could just have implemented the above example using tls streams. We could even use WebSockets using shoe.