useFileUrl()

useFileUrl fetches a short-lived URL for an attachment fileId. URLs are not stored on the message — ask when you need a preview.

Assistant.useFileUrl needs Pai.Provider, not ThreadProvider. Package-root useFileUrl needs both.

function AttachmentPreview({ part }: { part: { fileId: string } }) {
  const preview = Assistant.useFileUrl(part.fileId, { intent: "view" });
  if (preview.status !== "ready" || !preview.url) return null;
  return <img src={preview.url} alt="" />;
}

Import

const { url, status } = Assistant.useFileUrl(part.fileId, { intent: "view" });

Signature

function useFileUrl(
  fileId: string | null | undefined,
  options?: UseFileUrlOptions,
): FileUrlController;

Parameters

fileId: string | null | undefined

Attachment id from a message part. null / undefined keeps the hook idle.

options?: UseFileUrlOptions

intent?: "view" | "download"

ttlSeconds?: number

enabled?: boolean

When false, skips the request.

Defaults to true.

Returns

A FileUrlController.

FileUrlController

url: string | null

error: Error | null

retry: () => void

Force a fresh fetch.