fix: File upload example (BLO-1311) by matthewlipski · Pull Request #2996 · TypeCellOS/BlockNote

matthewlipski · 2026-08-21T12:53:09Z

Summary

This PR fixes the file upload example and related file upload code as tmpfiles changed their API and it no longer works for our use. To prevent issues like that happening in the future, we now just save the file as a base64 URL.

Closes @2967

Rationale

The example is broken.

Changes

Updated docs demo.
Updated file upload example.
Updated Uppy file panel example.
Updated and renamed uploadFilesToTmpFilesDotOrg_DEV_ONLY to uploadFile_DEV_ONLY.

Impact

N/A

Testing

N/A - TODO?

Screenshots/Video

N/A

Checklist

Code follows the project's coding standards.
Unit tests covering the new feature have been added.
All existing tests pass.
The documentation has been updated to reflect the new feature

Additional Notes

N/A

Summary by CodeRabbit

New Features
- Development file uploads now produce local base64 data URLs instead of relying on an external temporary-file service.
- Uppy image uploads support processing multiple completed files using the generated data URLs.
Documentation
- Updated file-upload guidance and examples to use local development uploads.
- Clarified that production applications should provide their own backend upload implementation.
Bug Fixes
- Updated image upload checks to recognize data URL sources.

vercel · 2026-08-21T12:53:15Z

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Project	Deployment	Actions	Updated (UTC)
blocknote	Ready	Preview	Aug 21, 2026 1:06pm
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coderabbitai · 2026-08-21T12:54:23Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Configuration used: Organization UI

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Run ID: 43ab0f64-0720-4cf0-9b1e-3507ffa78783

📥 Commits

Reviewing files that changed from the base of the PR and between d7c2890 and 9ccd1f8.

📒 Files selected for processing (3)

examples/01-basic/testing/src/App.tsx
packages/core/src/blocks/File/helpers/uploadFile_DEV_ONLY.ts
tests/src/unit/core/createTestEditor.ts

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📝 Walkthrough

Walkthrough

Changes

The PR replaces tmpfiles.org uploads with BlockNote’s development-only helper. The helper returns base64 data URLs. Examples, documentation, the Uppy panel, exports, and tests now use the local upload flow.

Local data URL uploads

Layer / File(s)	Summary
Development-only upload helper and examples `packages/core/src/blocks/File/helpers/uploadFile_DEV_ONLY.ts`, `packages/core/src/blocks/index.ts`, `docs/app/demo/...`, `examples/01-basic/testing/src/App.tsx`, `examples/02-backend/01-file-uploading/...`, `docs/content/docs/react/components/image-toolbar.mdx`, `playground/src/examples.gen.tsx`	`uploadFile_DEV_ONLY` reads files as data URLs. The export, examples, and documentation use the helper and describe backend replacement for production.
Uppy completion flow `examples/03-ui-components/11-uppy-file-panel/src/UppyFilePanel.tsx`	The Uppy panel removes its XHR uploader, processes completed files with `uploadFile_DEV_ONLY`, updates blocks with data URLs, and simplifies its exported upload function.
Test upload wiring `tests/src/unit/core/createTestEditor.ts`, `tests/src/end-to-end/images/images.test.tsx`	Test editors use `uploadFile_DEV_ONLY`, and the image test detects data URL sources.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to 9ccd1

This PR updates file-upload examples and helper usage to use base64 URLs; no actionable merge-blocking risk remains beyond normal checks and review.

Sequence Diagram(s)

sequenceDiagram
  participant Uppy
  participant uploadFile_DEV_ONLY
  participant BlockNoteEditor
  Uppy->>uploadFile_DEV_ONLY: Process each successful file
  uploadFile_DEV_ONLY-->>Uppy: Return base64 data URL
  Uppy->>BlockNoteEditor: Update block with file name and data URL

Suggested reviewers: nperez0111

Poem

A rabbit reads each file with care,
A data URL forms in air.
Uppy sends no bytes afar,
Each image stays just where they are.
Local blocks now hold the prize.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 71.43% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 9 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the primary change: fixing the file upload example.
Description check	✅ Passed	The description covers all required sections and accurately summarizes the base64 upload changes, but testing details and checklist items remain incomplete.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches 💡 1

📝 Generate docstrings 💡

Create stacked PR
Commit on current branch

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch fix-file-upload

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nperez0111

Can we change it from being exported? Otherwise fine to move off the actual upload path

nperez0111 · 2026-08-21T13:02:41Z

@@ -1,3 +1,5 @@
+import { uploadFile_DEV_ONLY } from "@blocknote/core";


I wouldn't really want this exported, I get that it is a shared util, but not one that needs to be actually packaged. Just copy-paste in the places that need it

nperez0111 · 2026-08-21T13:03:54Z

 export * from "./Code/helpers/toExternalHTML/createPreCode.js";
 export * from "./ToggleWrapper/createToggleWrapper.js";
-export * from "./File/helpers/uploadToTmpFilesDotOrg_DEV_ONLY.js";
+export * from "./File/helpers/uploadFile_DEV_ONLY.js";


oh we had this exported before? That is strange to me

Should I still remove the export then? Or keep as it was?

I'd remove it

pkg-pr-new · 2026-08-21T13:09:14Z

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commit: 9ccd1f8

github-actions · 2026-08-21T13:10:49Z

PR Preview Action v1.8.1
🚀 View preview at https://TypeCellOS.github.io/BlockNote/pr-preview/pr-2996/
Built to branch `gh-pages` at 2026-08-21 13:12 UTC. Preview will be ready when the GitHub Pages deployment is complete.

Replaced tmpfiles file uploads with local storage

d7c2890

nperez0111 reviewed Aug 21, 2026

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Added uncommitted files

9ccd1f8

vercel Bot deployed to Preview – blocknote August 21, 2026 13:05 View deployment

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fix: File upload example (BLO-1311) - #2996

fix: File upload example (BLO-1311)#2996
matthewlipski wants to merge 2 commits into
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matthewlipski commented Aug 21, 2026 •

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		@@ -1,3 +1,5 @@
		import { uploadFile_DEV_ONLY } from "@blocknote/core";

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