JSON-RPC over websocket with multicast service discovery with a browser compatible client

npm install --save microserv

const { Server, Service } = require('microserv')

const server = new Server('my-app', { port: 3000 })
const msgService = new Service('message')

msgService.register('getMessage', () => {
	return 'Hello, world!'
})

server.addService(msgService)
server.listen()
server.announce()

const http = require('http')
const { Server, Service } = require('microserv')

const server = new Server('my-app', { port: 3001 })
const mathService = new Service('math')

mathService.register('add', (a, b) => {
	return a + b
})

server.addService(mathService)

// Wait for the message service to be ready
server.need('message')
	.then(([ message ]) => {
		const app = http.createServer((req, res) => {
			res.statusCode = 200
			res.setHeader('Content-Type', 'text/plain')

			// Call the message service `getMessage` method
			message.getMessage()
				.then(msg => {
					res.end(msg)
					// { type: 'string', data: 'Hello, world!' }
				})
		})

		app.listen(8080, '127.0.0.1')
	})

server.listen()
server.announce()

const { Client } = require('microserv')

const client = new Client()

client.need('message', 'math')
	.then(([ message, math ]) => {
		message
			.getMessage()
			.then(msg => console.log(msg))

		math
			.add(1, 2)
			.then(sum => console.log(sum))
	})

client.connect('ws://localhost:3000')
client.connect('ws://localhost:3001')

const server = new Server('my-app', { port: 3001 })

Instantiate a client

Parameters:

• address {String}: The service namespace. Only services in the same namespace can connect to each other.
• options {Object}: Websocket options
  • port {Number}: Websocket port
  • interval {Number}: How often to announce the service (in ms). Defaults to 5000.
  • sever {http.Server|https.server}: A server to use as the websocket server. If set, will override port.
  • secure {Boolean}: Use secure websockets. Defaults to false.
  • serviceTransform {Function}: A function to transform the data returned from an rpc call. Defaults to noop.
  • authorization {Any}: Credentials to pass to Server when connecting
  • authorizeClient {Function}: A sync or async function to authorize a Client. Function is passed the Client's authorization credentials
  • dns {Object}: dns-discovery options

Add a service to the server, and announce the service to connected peers

Parameters:

• service {Service}: A Service instance

List required services. Resolves with each of the required services of type ClientService

Parameters:

• services {String}: Service names

Begin listening for peers

Announce the service on the network. Will reannounce the service at the interval provided via opts.

const service = new Service('my-service')

Instantiate a new Service

Parameters:

• name {String}: The service name that will be announced to peers

Register an rpc method with the service

Parameters:

• method {String}: The name of the method
• cb {Function}: The function to invoke when the rpc method is called
• resultType {String}: The type of data returned by the method. Defaults to typeof result

Emits an event via the websocket

Parameters:

• name {String}: The event name
• data {*}: The event data

Returned from server.need(). This should not be instantiated direclty.

Subscribe to a service event

Parameters:

• name {String}: The name of the event
• cb {Function}: The event callback

Each method registered with the service is exposed a method of the client service. Returns and object with data and type properties.

Emitted when the connection to the service is lost

Emitted when the connection to a lost service is reestablished

const client = new Client()

Instantiate a new Client

Parameters:

• opts {Object}: Options
  • serviceTransform {Function}: A function to transform the data returned from an rpc call. Defaults to noop.
  • authorization {Any}: Credentials to pass to Server when connecting
• rpcOpts {Object}: Options for rpc-websockets

Connect to a specific websocket server

Parameters:

• connection {String}: The server connection string (eg. ws://localhost:3001)

List required services. Resolves with each of the required services of type ClientService

Parameters:

• services {String}: Service names

Emitted when the connection to a service is closed

Emitted when the client fails authorization

npm run test

MIT License