Promise-based RPC client and server for web workers

Table of Contents

• Features
• Install
• Usage
• API
• Development

Features

• Promise-based API as easy as possible
• Load balancing with round robin strategy
• Transferables support
• Server events
• Error handling
• High performance

Install

npm install --save @librpc/web

or download dev or prod version

Usage

// server.js
import { Server as RpcServer } from '@librpc/web'

function wait (time) {
  return new Promise(resolve => setTimeout(resolve, time))
}

self.rpcServer = new RpcServer({
  add ({ x, y }) { return x + y },
  task () { return wait(1000) },
  error () { return err },
  transfer (buffer) { return { buffer }}
})

// client.js
import { Client as RpcClient } from '@librpc/web'

var worker = new window.Worker('server.js')

var rpcClient = new RpcClient({ workers: [worker] })

rpcClient.call('add', { x: 1, y: 1})
  .then(res => console.log(res)) // 2

rpcClient.call('length')
  .catch(err => console.log(err)) // Unknown RPC method "length"

rpcClient.call('task', null, { timeout: 100 })
  .catch(err => console.log(err)) // Timeout exceeded for RPC method "task"

rpcClient.call('error')
  .catch(err => console.log(err)) // ReferenceError: err is not defined

rpcClient.call('transfer', new ArrayBuffer(0xff))
  .then(res => console.log(res.buffer)) // ArrayBuffer(255)

API

WebRPC.Server

#constructor(methods: { [string]: (*) => Promise<*> | * })

var server = new RpcServer({
  add ({ x, y }) { return x + y },
  sub ({ x, y }) { return x - y },
  mul ({ x, y }) { return x * y },
  div ({ x, y }) { return x / y },
  pow ({ x, y }) { return x ** y }
})

Every passed method becomes remote procedure. It can return Promise if it is needed. Only ArrayBuffers will be transferred automatically (not TypedArrays). Errors thrown by procedures would be handled by server.

#emit(eventName: string, data: *)

setInterval(() => {
  server.emit('update', Date.now())
}, 50)

Trigger server event.

WebRPC.Client

#constructor(options: { workers: Array<Worker> })

var worker = new window.Worker('server.js')
var client = new RpcClient({ workers: [worker] })

Client could be connected to several workers for better CPU utilization. Requests are sent to an exact worker by round robin algorithm.

#call(method: string, data: *, { timeout = 2000 } = {}): Promise<*>

client.call('pow', { x: 2, y: 10 })
  .then(result => console.log(result))

Remote procedure call. Only ArrayBuffers will be transferred automatically (not TypedArrays).

Error would be thrown, if:

• it happened during procedure
• you try to call an unexisted procedure
• procedure execution takes more than timeout

#on(eventName: string, listener: (*) => void)

function listener (data) { console.log(data) }
client.on('update', listener)

Start listen to server events.

#off(eventName: string, listener: (*) => void)

client.off('update', listener)

Stop listen to server events.

Development

Command	Description
npm run check	Check standard code style by snazzy
npm run build	Wrap source code in UMD by rollup
npm run test	Run tests by tape and compute code coverage by nyc
npm run min	Minify code by UglifyJS2