Method probeReadWrite

packages/ai-sandbox-sprites/src/client.ts:474–512

Write a sentinel and read it back; throws unless the round-trip matches.

(
    name: string,
    path: string,
    marker: string,
    signal?: AbortSignal,
  )

  /** Write a sentinel and read it back; throws unless the round-trip matches. */
  private async probeReadWrite(
    name: string,
    path: string,
    marker: string,
    signal?: AbortSignal,
  ): Promise<void> {
    const attemptSignal = signal
      ? AbortSignal.any([signal, AbortSignal.timeout(8000)])
      : AbortSignal.timeout(8000)
    const writeUrl = this.spritePath(
      name,
      `/fs/write?path=${encodeURIComponent(path)}`,
    )
    const writeRes = await fetch(writeUrl, {
      method: 'PUT',
      headers: this.headers({ 'content-type': 'application/octet-stream' }),
      body: new TextEncoder().encode(marker),
      signal: attemptSignal,
    })
    await writeRes.body?.cancel()
    if (!writeRes.ok) throw new Error(`probe write HTTP ${writeRes.status}`)

    const readUrl = this.spritePath(
      name,
      `/fs/read?path=${encodeURIComponent(path)}`,
    )
    const readRes = await fetch(readUrl, {
      method: 'GET',
      headers: this.headers(),
      signal: attemptSignal,
    })
    if (!readRes.ok) {
      await readRes.body?.cancel()
      throw new Error(`probe read HTTP ${readRes.status}`)
    }
    if ((await readRes.text()) !== marker) {
      throw new Error('probe read mismatch')
    }
  }

  private async deleteSentinel(name: string, path: string): Promise<void> {
    const res = await fetch(