Handling file uploads on your own server is a recipe for disaster. It consumes memory, bandwidth, and CPU. The professional solution is Presigned URLs.
How it works:
- Request: The client asks your backend for permission to upload.
- Generate: Your server uses the AWS SDK to create a temporary, secure URL.
- Upload: The client uploads the file directly to S3 using that URL.
- Callback: S3 notifies your server (or the client tells the server) that the upload is complete.
Security Benefits:
- Your server never sees the raw file data.
- You can restrict uploads by file type and size at the AWS level.
- URLs expire quickly (e.g., in 5 minutes).
Direct-to-cloud uploads are faster for the user and cheaper for you.