Class PeerDataChannel

app/utils/PeerDataChannel.ts:13–244

 * 封装用于点对点数据传输的 WebRTC 数据通道
 */
export class PeerDataChannel {
  private static readonly DEFAULT_BLOCK_SIZE = 32768

  private pc: RTCPeerConnection
  private dc: RTCDataChannel | null = null
  private receiveData: {
    startTime: number
    offset: number
    count: number
    type: string
    chunks: (string | ArrayBuffer)[]
  } = { startTime: 0, offset: 0, count: 0, type: '', chunks: [] }
  private sendPromiseReject: ((reason?: any) => void) | null = null
  private eventQueue: EventQueue<ArrayBuffer | string>
  private blockSize: number

  public onReceive: (
    data: ArrayBuffer | string,
    info: { size: number; duration: number }
  ) => Promise<void> = async () => {}
  public onSDP: (sdp: RTCSessionDescriptionInit) => void = () => {}
  public onICECandidate: (candidate: RTCIceCandidate) => void = () => {}
  public onError: (e: Error) => void = () => {}
  public onConnected: () => void = () => {}
  public onDispose: () => void = () => {}
  public onOpen: () => void = () => {}

  /**
   * 创建一个新的 PeerDataChannel 实例
   * @param config 配置
   */
  constructor(config: PeerDataChannelConfig = {}) {
    this.blockSize = config.blockSize || PeerDataChannel.DEFAULT_BLOCK_SIZE
    this.eventQueue = new EventQueue(this.onData.bind(this))
    this.pc = new RTCPeerConnection({ iceServers: config.iceServers })

    this.setupPeerConnection()

    if (config.initializeDataChannel) {
      this.initializeDataChannel()
    }
  }

  private setupPeerConnection(): void {
    this.pc.ondatachannel = this.handleDataChannel.bind(this)
    this.pc.onnegotiationneeded = this.reNegotiation.bind(this)
    this.pc.onicecandidate = (e) => e.candidate && this.onICECandidate(e.candidate)
    this.pc.onicecandidateerror = (e) => {
      // console.warn(e)
      // ingore
    }
    this.pc.onconnectionstatechange = this.handleConnectionStateChange.bind(this)
  }

  private handleDataChannel(e: RTCDataChannelEvent): void {
    this.dc = e.channel
    this.setupDataChannel()
  }