elysia-file-upload-multer

What problem does it solve?

This Skill eliminates the friction and security risks of implementing file upload functionality for Elysia.js (Bun runtime) backends, avoiding brittle middleware hacks, silent nginx 413 errors, and path traversal vulnerabilities that plague ad-hoc implementations.

Core Features & Use Cases

• Hand-rolled multipart parser (recommended for Elysia 1.2): Lightweight 80-line implementation using native Web Streams API, no extra dependencies, with built-in per-file and total request size limits.
• Legacy Multer integration: Compatible option for older Elysia projects, with static file serving setup and MIME type filtering for allowed file types.
• End-to-end safety and operational guardrails: Includes random on-disk storage keys to prevent path traversal, nginx configuration guidance to avoid edge-level request failures, and proper download handling to eliminate cross-tab browser warnings.
• Use Case: A CRM development team can use this Skill to quickly add user attachment upload (PDFs, images, documents) to their Elysia API, with full backend route code, storage setup, and frontend integration examples.

Quick Start

Use the elysia-file-upload-multer skill to implement a secure 50MB file upload endpoint for your Elysia.js backend that accepts PDF and image attachments from authenticated users.