frontend/src/lib/iceCandidateQueue.ts - main - nayvok/livecoding

frontend/src/lib/iceCandidateQueue.ts
85 строк2 KB
nayvok
fix: harden sessions and WebRTC recovery
17 июн 2026, 22:02
17 июн 2026, 22:0237b9a92
export type IceCandidateDisposition = 'ready' | 'pending' | 'stale'

export interface IceCandidateQueue {
  add: (
    candidate: RTCIceCandidateInit,
    disposition: IceCandidateDisposition,
    addCandidate: (candidate: RTCIceCandidateInit) => Promise<void>,
  ) => Promise<boolean>
  flush: (
    getDisposition: (
      candidate: RTCIceCandidateInit,
    ) => IceCandidateDisposition,
    addCandidate: (candidate: RTCIceCandidateInit) => Promise<void>,
  ) => Promise<unknown[]>
  clear: () => void
}

export function getIceCandidateDisposition(
  candidate: RTCIceCandidateInit,
  remoteDescription: RTCSessionDescription | null,
  signalingState: RTCSignalingState,
): IceCandidateDisposition {
  if (!remoteDescription) return 'pending'
  if (signalingState === 'closed') return 'stale'

  const candidateUfrag = candidate.usernameFragment
  if (candidateUfrag && remoteDescription.sdp) {
    const remoteUfrags = remoteDescription.sdp
      .split(/\r?\n/)
      .filter((line) => line.startsWith('a=ice-ufrag:'))
      .map((line) => line.slice('a=ice-ufrag:'.length))
    if (remoteUfrags.length > 0) {
      const matchesCurrentDescription = remoteUfrags.includes(candidateUfrag)
      if (signalingState === 'have-local-offer') {
        return matchesCurrentDescription ? 'stale' : 'pending'
      }
      return matchesCurrentDescription ? 'ready' : 'stale'
    }
  }

  // ICE-restart, ждем новый answer.
  return signalingState === 'have-local-offer' ? 'pending' : 'ready'
}

export function createIceCandidateQueue(): IceCandidateQueue {
  const pending: RTCIceCandidateInit[] = []

  return {
    async add(candidate, disposition, addCandidate) {
      if (disposition === 'stale') {
        return false
      }
      if (disposition === 'pending') {
        if (pending.length >= 256) {
          pending.shift()
        }
        pending.push(candidate)
        return false
      }
      await addCandidate(candidate)
      return true
    },
    async flush(getDisposition, addCandidate) {
      const candidates = pending.splice(0)
      const errors: unknown[] = []
      for (const candidate of candidates) {
        const disposition = getDisposition(candidate)
        if (disposition === 'pending') {
          pending.push(candidate)
          continue
        }
        if (disposition === 'stale') continue
        try {
          await addCandidate(candidate)
        } catch (err) {
          errors.push(err)
        }
      }
      return errors
    },
    clear() {
      pending.length = 0
    },
  }
}