Function downloadFalMedia

apps/sim/lib/media/falai.ts:194–228

(
  url: string
)

/** Securely download a generated media URL (or inline data URI) to a buffer. */
export async function downloadFalMedia(
  url: string
): Promise<{ buffer: Buffer; contentType: string }> {
  if (url.startsWith('data:')) {
    const match = /^data:([^;]+);base64,(.+)$/u.exec(url)
    if (!match) throw new Error('Invalid data URI media response')
    const buffer = Buffer.from(match[2], 'base64')
    assertKnownSizeWithinLimit(buffer.length, MAX_MEDIA_BYTES, 'inline media response')
    return { contentType: match[1], buffer }
  }

  const validation = await validateUrlWithDNS(url, 'mediaUrl')
  if (!validation.isValid || !validation.resolvedIP) {
    throw new Error(validation.error || 'Generated media URL failed validation')
  }

  const response = await secureFetchWithPinnedIP(url, validation.resolvedIP, {
    method: 'GET',
    maxResponseBytes: MAX_MEDIA_BYTES,
  })
  if (!response.ok) {
    await readResponseTextWithLimit(response, {
      maxBytes: DEFAULT_MAX_ERROR_BODY_BYTES,
      label: 'generated media error response',
    }).catch(() => '')
    throw new Error(`Failed to download generated media: ${response.status}`)
  }

  const contentType = response.headers.get('content-type') || 'application/octet-stream'
  const buffer = await readResponseToBufferWithLimit(response, {
    maxBytes: MAX_MEDIA_BYTES,
    label: 'generated media download',
  })
  return { buffer, contentType }
}

export { logger as falMediaLogger }