backend/src/sessionCreationGuard.ts - main - nayvok/livecoding

backend/src/sessionCreationGuard.ts
68 строк2 KB
nayvok
fix: harden sessions and WebRTC recovery
17 июн 2026, 22:02
17 июн 2026, 22:0237b9a92
export interface SessionCreationLimiterOptions {
  limit: number
  windowMs: number
  maxClients?: number
}

interface WindowState {
  startedAt: number
  count: number
}

export interface SessionCreationLimiter {
  tryAcquire: (clientKey: string, now?: number) => boolean
}

export function getRateLimitClientKey(
  forwardedHeader: string | string[] | undefined,
  remoteAddress: string | undefined,
): string {
  const forwarded = Array.isArray(forwardedHeader)
    ? forwardedHeader[0]
    : forwardedHeader
  const originalAddress = forwarded
    ?.split(',')
    .map((value) => value.trim())
    .find(Boolean)
  return originalAddress ?? remoteAddress ?? 'unknown'
}

export function createSessionCreationLimiter({
  limit,
  windowMs,
  maxClients = 10_000,
}: SessionCreationLimiterOptions): SessionCreationLimiter {
  const normalizedLimit = Number.isSafeInteger(limit) && limit > 0 ? limit : 1
  const normalizedWindowMs =
    Number.isFinite(windowMs) && windowMs > 0 ? windowMs : 60_000
  const normalizedMaxClients =
    Number.isSafeInteger(maxClients) && maxClients > 0 ? maxClients : 10_000
  const windows = new Map<string, WindowState>()

  return {
    tryAcquire(clientKey, now = Date.now()) {
      const current = windows.get(clientKey)
      if (current && now - current.startedAt < normalizedWindowMs) {
        if (current.count >= normalizedLimit) return false
        current.count += 1
        return true
      }

      if (!current && windows.size >= normalizedMaxClients) {
        for (const [key, state] of windows) {
          if (now - state.startedAt >= normalizedWindowMs) {
            windows.delete(key)
          }
        }
        if (windows.size >= normalizedMaxClients) return false
      }

      if (!current || now - current.startedAt >= normalizedWindowMs) {
        windows.set(clientKey, { startedAt: now, count: 1 })
        return true
      }

      return false
    },
  }
}