Handling file uploads for modern developer

wroclove.rb 2019 talk by Janko Marohnić sharing best practices for handling file uploads in web applications. Structured around four themes: (1) server-side validation — file size, MIME type determined from content via magic bytes (not the Content-Type header which comes from the extension), image dimensions to prevent image bombs, and custom metadata that should be persisted; (2) processing — on-upload vs on-the-fly, using the image_processing gem with either ImageMagick (mini_magick) or libvips backends (libvips ~3–5× faster); (3) upload UX — async direct uploads to S3 driven by the Uppy JavaScript library, with built-in UI components (file input, progress bar, drag-and-drop, dashboard); (4) resumable uploads via S3 multipart or the generic tus protocol. Ends with Q&A covering DDoS protection via signed URLs, orphan-file avoidance via temporary storage, testing with MinIO, and a request for Ruby bindings for imageflow.