Secure Upload Pipeline in Flask
Reference architecture for building safe file-ingest paths in Flask services.
security
code
document
image
archive
Separate Ingest From Processing
Your Flask request handler should do minimal synchronous work: authenticate, enforce coarse limits, persist file to object storage/quarantine, and enqueue processing jobs. Heavy parsing and conversions belong in workers, not request threads.
- Synchronous: auth, size checks, temporary object write, job enqueue.
- Asynchronous: antivirus, media transcode, OCR, metadata extraction, indexing.
Harden Storage and Execution Boundaries
Never trust filenames for filesystem paths. Use generated object IDs and immutable storage paths. Keep processing workers in restricted containers with read-only dependencies and minimum network access. Apply decompression and recursion limits for archives.
Expose Clear State Machine to Clients
A visible upload state machine reduces support load and lets clients implement retries or fallbacks correctly. This also improves auditability for compliance reviews.
accepted -> queued -> scanning -> transformed -> ready
\-> rejected(reason_code)