Multipart

Large files upload in parts. Each part is a presigned PUT, and your backend runs the session: init, signing, complete, and abort.

Flow: init → signPart (per part) → complete or abort · listParts to resume.

The browser uses multipart for files of at least 50 MiB when the route's catalog entry has multipart: true.

InitCopy Anchor Link

Same file fields as a simple upload, without checksum.

Your backend picks the part layout. Return partSize (every part but the last) and partCount; the browser slices the file exactly that way. Set checksum: true to make every part send a SHA-256. The ticket goes with every later call, so it must identify the route, key, and upload id.

Sign partCopy Anchor Link

Sign the part's exact byte size into the URL, and the checksum when there is one. The browser sends exactly headers on the PUT. When a part URL expires mid-upload, the browser calls signPart again rather than reusing it.

List parts, complete, and abortCopy Anchor Link

These three take only the ticket.

listParts returns the parts S3 already has, so a resumed upload sends only the rest. Read every page of S3's ListParts.

complete lists the parts on the server, completes the upload, and returns the object HeadObject reports, plus the upload id.

abort ends the session. The browser calls it when the user cancels.

When a resumed upload's ticket has expired, or the upload is gone, throw UPLOAD_TICKET_EXPIRED, UPLOAD_TICKET_INVALID, or OBJECT_NOT_FOUND. The browser then aborts, forgets the stored upload, and starts over.

ExampleCopy Anchor Link

@dimah-s3/server mounts these under /api/s3/presign/multipart/*.

import type {
  MultipartAbortResponse,
  MultipartCompleteResponse,
  MultipartInitPayload,
  MultipartInitResponse,
  MultipartListPartsResponse,
  MultipartPartResponse,
  MultipartSignPartPayload,
  TicketPayload,
  S3RequestOptions,
} from "@dimah-s3/core";
import { $fetch, call } from "./fetch";

const post = <T>(path: string, body: object, options?: S3RequestOptions) =>
  $fetch<T>(`/multipart${path}`, { method: "POST", body, ...call(options) });

export const init = (
  payload: MultipartInitPayload,
  options?: S3RequestOptions,
) => post<MultipartInitResponse>("/init", payload, options);

export const signPart = (
  payload: MultipartSignPartPayload,
  options?: S3RequestOptions,
) => post<MultipartPartResponse>("/part", payload, options);

export const listParts = (payload: TicketPayload, options?: S3RequestOptions) =>
  post<MultipartListPartsResponse>("/parts", payload, options);

export const complete = (payload: TicketPayload, options?: S3RequestOptions) =>
  post<MultipartCompleteResponse>("/complete", payload, options);

export const abort = (payload: TicketPayload, options?: S3RequestOptions) =>
  post<MultipartAbortResponse>("/abort", payload, options);

$fetch and call come from the skeleton.