remix-run/remix form-data-parser@1.1.0

form-data-parser v1.1.0

on GitHub

Minor Changes

• Add a @remix-run/form-data-parser/future entrypoint where parseFormData() streams file uploads to your upload handler instead of buffering them. Future APIs are not stable and may change in any release, but they are a good indication of where this package will land in its next major release. (#12030)

  The future FileUpload is yielded as soon as the part's headers arrive, and its contents stream from the request body as you read them, so you can write a large upload to storage without holding it in memory. It has the same shape as File, with these differences:

  • Its contents can be read once, and only while the upload handler is running
  • size throws until the contents have been read
  • slice() is not supported

  If the upload handler returns a FileUpload without reading it, or there is no upload handler, parseFormData() reads it into a regular File and puts that in the FormData.

  import { parseFormData } from '@remix-run/form-data-parser/future'
  
  let formData = await parseFormData(request, async (fileUpload) => {
    let storageKey = crypto.randomUUID()
    await fileStorage.set(storageKey, fileUpload)
    return storageKey
  })

  Streaming makes large uploads faster and keeps memory flat, because the upload handler can start writing a file as soon as its first bytes arrive instead of after the whole file has been buffered. Measured on Node.js 24.18 with an Apple M5 Pro, as the median of 7 runs that each use a fresh process, with an upload handler that streams each file to storage:

  Request	Total time (stable → future)	Time until the upload handler is called	Peak memory growth
  1 × 100 MiB file	67.7 ms → 36.6 ms	45.4 ms → 0.2 ms	396 MiB → 29 MiB
  5 × 20 MiB files	60.2 ms → 36.3 ms	9.5 ms → 0.2 ms	165 MiB → 19 MiB
  10 fields and an 8 KiB file	0.58 ms → 0.52 ms	0.51 ms → 0.42 ms	No measurable change

  ParseFormDataOptions, FormDataParseError, MaxFilesExceededError, and the re-exported multipart parser errors are shared with the stable entrypoint, so instanceof checks work with either.

  If your app handles file uploads, please give @remix-run/form-data-parser/future a try and tell us how it goes in GitHub Discussions. We'd especially like to hear about anything that breaks, behaves unexpectedly, or feels awkward, since that feedback will shape the next major release.

Patch Changes

• Fixed a memory leak when streaming uploaded files on Node.js versions before 24.20.0 and 26.6.0. Reading a FileUpload with file.stream(), including when saving it with writeFile from @remix-run/fs or the filesystem backend of @remix-run/file-storage, kept every uploaded file in memory for the life of the process because of a Node.js bug (nodejs/node#63574). FileUpload now streams its contents in slices, so uploaded files are freed once they are no longer referenced. (#12029)

• Bumped @remix-run/* dependencies:

  • headers@1.0.1
  • multipart-parser@1.1.0