2021-07-17 14:08:25 +02:00

417 lines
12 KiB
TypeScript

import EventEmitter from 'eventemitter3'
import { Logger } from '../utils/logger'
export const OPCODE = {
MOVE: 0x01,
SCROLL: 0x02,
KEY_DOWN: 0x03,
KEY_UP: 0x04,
BTN_DOWN: 0x05,
BTN_UP: 0x06,
} as const
export interface WebRTCStats {
bitrate: number
packetLoss: number
fps: number
width: number
height: number
muted?: boolean
}
export interface ICEServer {
urls: string
username: string
credential: string
}
export interface NekoWebRTCEvents {
connected: () => void
disconnected: (error?: Error) => void
track: (event: RTCTrackEvent) => void
candidate: (candidate: RTCIceCandidateInit) => void
stats: (stats: WebRTCStats) => void
['cursor-position']: (data: { x: number; y: number }) => void
['cursor-image']: (data: { width: number; height: number; x: number; y: number; uri: string }) => void
}
export class NekoWebRTC extends EventEmitter<NekoWebRTCEvents> {
private _peer?: RTCPeerConnection
private _channel?: RTCDataChannel
private _track?: MediaStreamTrack
private _state: RTCIceConnectionState = 'disconnected'
private _candidates: RTCIceCandidateInit[] = []
private _log: Logger
private _statsStop?: () => void
constructor() {
super()
this._log = new Logger('webrtc')
}
get supported() {
return typeof RTCPeerConnection !== 'undefined' && typeof RTCPeerConnection.prototype.addTransceiver !== 'undefined'
}
get open() {
return (
typeof this._peer !== 'undefined' && typeof this._channel !== 'undefined' && this._channel.readyState == 'open'
)
}
get connected() {
return this.open && ['connected', 'checking', 'completed'].includes(this._state)
}
public async setCandidate(candidate: RTCIceCandidateInit) {
if (!this._peer) {
this._candidates.push(candidate)
return
}
this._peer.addIceCandidate(candidate)
this._log.debug(`adding remote ICE candidate`, candidate)
}
public async connect(sdp: string, iceServers: ICEServer[]): Promise<string> {
if (!this.supported) {
throw new Error('browser does not support webrtc')
}
if (this.connected) {
throw new Error('attempting to create peer while connected')
}
this._log.info(`connecting`)
this._peer = new RTCPeerConnection({ iceServers })
if (iceServers.length == 0) {
this._log.warn(`iceservers are empty`)
}
this._peer.onicecandidate = (event: RTCPeerConnectionIceEvent) => {
if (!event.candidate) {
this._log.debug(`sent all remote ICE candidates`)
return
}
const init = event.candidate.toJSON()
this.emit('candidate', init)
this._log.debug(`sending remote ICE candidate`, init)
}
this._peer.onconnectionstatechange = (event) => {
this._log.debug(`peer connection state changed: ${this._peer!.connectionState}`)
}
this._peer.oniceconnectionstatechange = (event) => {
this._state = this._peer!.iceConnectionState
this._log.debug(`peer ice connection state changed: ${this._peer!.iceConnectionState}`)
switch (this._state) {
// We don't watch the disconnected signaling state here as it can indicate temporary issues and may
// go back to a connected state after some time. Watching it would close the video call on any temporary
// network issue.
case 'closed':
case 'failed':
this.onDisconnected(new Error('peer ' + this._state))
break
}
}
this._peer.onsignalingstatechange = (event) => {
const state = this._peer!.iceConnectionState
this._log.debug(`peer signaling state changed: ${state}`)
switch (state) {
// The closed signaling state has been deprecated in favor of the closed iceConnectionState.
// We are watching for it here to add a bit of backward compatibility.
case 'closed':
this.onDisconnected(new Error('peer ' + state))
break
}
}
this._peer.ontrack = this.onTrack.bind(this)
this._peer.ondatachannel = this.onDataChannel.bind(this)
this._peer.addTransceiver('audio', { direction: 'recvonly' })
this._peer.addTransceiver('video', { direction: 'recvonly' })
return await this.offer(sdp)
}
public async offer(sdp: string) {
if (!this._peer) {
throw new Error('attempting to set offer for nonexistent peer')
}
this._peer.setRemoteDescription({ type: 'offer', sdp })
if (this._candidates.length > 0) {
for (const candidate of this._candidates) {
this._peer.addIceCandidate(candidate)
}
this._log.debug(`added ${this._candidates.length} remote ICE candidates`, this._candidates)
this._candidates = []
}
const answer = await this._peer.createAnswer()
this._peer!.setLocalDescription(answer)
if (!answer.sdp) {
throw new Error('sdp answer is empty')
}
return answer.sdp
}
public disconnect() {
if (typeof this._channel !== 'undefined') {
// unmount all events
this._channel.onerror = () => {}
this._channel.onmessage = () => {}
this._channel.onopen = () => {}
this._channel.onclose = () => {}
try {
this._channel.close()
} catch (err) {}
this._channel = undefined
}
if (typeof this._peer != 'undefined') {
// unmount all events
this._peer.onicecandidate = () => {}
this._peer.onconnectionstatechange = () => {}
this._peer.oniceconnectionstatechange = () => {}
this._peer.onsignalingstatechange = () => {}
this._peer.ontrack = () => {}
this._peer.ondatachannel = () => {}
try {
this._peer.close()
} catch (err) {}
this._peer = undefined
}
this._track = undefined
this._state = 'disconnected'
this._candidates = []
}
public send(event: 'wheel' | 'mousemove', data: { x: number; y: number }): void
public send(event: 'mousedown' | 'mouseup' | 'keydown' | 'keyup', data: { key: number }): void
public send(event: string, data: any): void {
if (!this.connected) {
this._log.warn(`attempting to send data while disconnected`)
return
}
let buffer: ArrayBuffer
let payload: DataView
switch (event) {
case 'mousemove':
buffer = new ArrayBuffer(7)
payload = new DataView(buffer)
payload.setUint8(0, OPCODE.MOVE)
payload.setUint16(1, 4)
payload.setUint16(3, data.x)
payload.setUint16(5, data.y)
break
case 'wheel':
buffer = new ArrayBuffer(7)
payload = new DataView(buffer)
payload.setUint8(0, OPCODE.SCROLL)
payload.setUint16(1, 4)
payload.setInt16(3, data.x)
payload.setInt16(5, data.y)
break
case 'keydown':
buffer = new ArrayBuffer(7)
payload = new DataView(buffer)
payload.setUint8(0, OPCODE.KEY_DOWN)
payload.setUint16(1, 4)
payload.setUint32(3, data.key)
break
case 'keyup':
buffer = new ArrayBuffer(7)
payload = new DataView(buffer)
payload.setUint8(0, OPCODE.KEY_UP)
payload.setUint16(1, 4)
payload.setUint32(3, data.key)
break
case 'mousedown':
buffer = new ArrayBuffer(7)
payload = new DataView(buffer)
payload.setUint8(0, OPCODE.BTN_DOWN)
payload.setUint16(1, 4)
payload.setUint32(3, data.key)
break
case 'mouseup':
buffer = new ArrayBuffer(7)
payload = new DataView(buffer)
payload.setUint8(0, OPCODE.BTN_UP)
payload.setUint16(1, 4)
payload.setUint32(3, data.key)
break
default:
this._log.warn(`unknown data event: ${event}`)
return
}
this._channel!.send(buffer)
}
private onTrack(event: RTCTrackEvent) {
this._log.debug(`received ${event.track.kind} track from peer: ${event.track.id}`, event)
const stream = event.streams[0]
if (!stream) {
this._log.warn(`no stream provided for track ${event.track.id}(${event.track.label})`)
return
}
if (event.track.kind === 'video') {
this._track = event.track
}
this.emit('track', event)
}
private onDataChannel(event: RTCDataChannelEvent) {
this._log.debug(`received data channel from peer: ${event.channel.label}`, event)
this._channel = event.channel
this._channel.binaryType = 'arraybuffer'
this._channel.onerror = this.onDisconnected.bind(this, new Error('peer data channel error'))
this._channel.onmessage = this.onData.bind(this)
this._channel.onopen = this.onConnected.bind(this)
this._channel.onclose = this.onDisconnected.bind(this, new Error('peer data channel closed'))
}
private onData(e: MessageEvent) {
const payload = new DataView(e.data)
const event = payload.getUint8(0)
const length = payload.getUint16(1)
switch (event) {
case 1:
this.emit('cursor-position', {
x: payload.getUint16(3),
y: payload.getUint16(5),
})
break
case 2:
const data = e.data.slice(11, length - 11)
// TODO: get string from server
const blob = new Blob([data], { type: 'image/png' })
const reader = new FileReader()
reader.onload = (e) => {
this.emit('cursor-image', {
width: payload.getUint16(3),
height: payload.getUint16(5),
x: payload.getUint16(7),
y: payload.getUint16(9),
uri: String(e.target!.result),
})
}
reader.readAsDataURL(blob)
break
default:
this._log.warn(`unhandled webrtc event '${event}'.`, payload)
}
}
private onConnected() {
if (!this.connected) {
this._log.warn(`onConnected called while being disconnected`)
return
}
this._log.info(`connected`)
this.emit('connected')
this._statsStop = this.statsEmitter()
}
private onDisconnected(reason?: Error) {
this.disconnect()
this._log.info(`disconnected:`, reason?.message)
this.emit('disconnected', reason)
if (this._statsStop && typeof this._statsStop === 'function') {
this._statsStop()
this._statsStop = undefined
}
}
private statsEmitter(ms: number = 2000) {
let bytesReceived: number
let timestamp: number
let framesDecoded: number
let packetsLost: number
let packetsReceived: number
const timer = setInterval(async () => {
if (!this._peer) return
let stats: RTCStatsReport | undefined = undefined
if (this._peer.getStats.length === 0) {
stats = await this._peer.getStats()
} else {
// callback browsers support
await new Promise((res, rej) => {
//@ts-ignore
this._peer.getStats((stats) => res(stats))
})
}
if (!stats) return
let report: any = null
stats.forEach(function (stat) {
if (stat.type === 'inbound-rtp' && stat.kind === 'video') {
report = { ...stat }
}
})
if (report === null) return
if (timestamp) {
const bytesDiff = (report.bytesReceived - bytesReceived) * 8
const tsDiff = report.timestamp - timestamp
const framesDecodedDiff = report.framesDecoded - framesDecoded
const packetsLostDiff = report.packetsLost - packetsLost
const packetsReceivedDiff = report.packetsReceived - packetsReceived
this.emit('stats', {
bitrate: (bytesDiff / tsDiff) * 1000,
packetLoss: (packetsLostDiff / (packetsLostDiff + packetsReceivedDiff)) * 100,
fps: Number(report.framesPerSecond || framesDecodedDiff / (tsDiff / 1000)),
width: report.frameWidth || NaN,
height: report.frameHeight || NaN,
muted: this._track?.muted,
})
}
bytesReceived = report.bytesReceived
timestamp = report.timestamp
framesDecoded = report.framesDecoded
packetsLost = report.packetsLost
packetsReceived = report.packetsReceived
}, ms)
return function () {
clearInterval(timer)
}
}
}