I contributed to Upup’s React file uploader. My work covered cloud-storage integrations, signed upload URLs, previews, responsive styling, drag-and-drop, and tests.
What it does
Upup lets developers add file uploads without building the picker, previews, progress, and storage integration from scratch. The current product supports six frontend frameworks; my contributions were to the earlier React uploader and its storage layer.
Hardest challenge
Files go straight from the user’s browser to the customer’s own S3 or Azure storage, so the browser must never hold the storage keys. A server signs each upload with a short-lived URL instead, and the two providers sign in different ways. The uploader still had to behave the same for both: one set of progress, previews and errors, whichever storage sat behind it.
What I worked on
- Presigned URLs for S3-compatible storage and Azure
- S3 signing tests for URL generation
- Responsive React UI and file-preview improvements
- Drag-and-drop during previews
Lessons learned
Storage contracts and UI state need to agree about what an upload is doing. Tests around URL signing and fixes to previews and drag-and-drop made those boundaries easier to maintain.
Evidence and status
Live demo and public source show the current product.