socket-requests

A simple wrapper around socket.io for sending requests that generate multiple responses.

Installation

npm install socket-requests

Usage

Set up your socket.io like normal. Then do this:

// client
var request = require('socket-requests').request;
var socket = io('http://localhost:5000/'); // as usual

request(socket, 'ping-pong', { query: "Ping" }, function (response) {
    console.log(response);
}).then(function (responses) {
    console.log(responses);
});

// server
var listen = require('socket-requests').listen;

io.on('connection', function (socket) {
    listen(socket, 'ping-pong', (request, send) => {
        send(request.query + ' pong.', true);

        setTimeout(function () {
            send('Puff!');
        }, 1000);
    });
});

The above example will print the following on the client:

Ping pong.
Puff!
[ "Ping pong." , "Puff!" ]

API

function listen(socket, name, handler)

This is the server-side part. Listen on the socket for events of type name, sending their data to the handler.

Multiple responses via send callback

The handler receives a callback for replying to the request as the second parameter. The callback is of signature

function send (result, keepalive = false) { /* ... */ }

If keepalive is true, there are more responses to come, otherwise the client is notified about the end of the response stream.

Single reponse via return value or promise

If the handler returns a value, this value is sent to the client. The handler may also return a promise, whose return value is sent to the client upon resolution. Both cases terminate the response stream, so return undefined in your handler if you use the send callback asynchronously and cannot make sure to resolve your handler Promise only after you have sent your last response.

function request(socket, name, request [, partialResultHandler] )

This function enriches the passed request data with a timestamp and sends it through the socket. Every subsequent response on that socket matching event that contains the original request's timestamp is considered a reply to the request. All responses are collected in an array. The function returns a promise that is resolved with the array of responses once the server sends no keepalive, hence signals the response stream to terminate.

If a partialResultHandler is supplied, it is called once for every reponse to the request.

Usage without Socket.IO

Since this is a simple wrapper using only .on, .off and .emit functions, you can simply use this library with any node standard EventEmitter, as seen in the examples.