Copyparty

Copyparty is a portable file server that turns almost any device into a file-sharing hub reachable from any web browser. One self-contained Python file (a 0.6 MB SFX, or a 6 MiB Windows .exe) serves HTTP/HTTPS, WebDAV, FTP(S), SFTP, TFTP, and a minimal SMB/CIFS server simultaneously, announcing itself on the LAN via mDNS/SSDP. The only mandatory dependency is Jinja2 — every other feature (thumbnails, audio transcoding, SFTP, argon2 password hashing) degrades gracefully if its optional library is missing.

Its flagship feature is up2k, an upload protocol with resumable, segmented, checksummed, and parallel uploads. Files are sliced into adaptive chunks (1 MiB base, growing until the file has ≤256 chunks), each chunk hashed, and the chunk-hash list plus size and a per-server salt folds into a 44-character content address called a wark. Chunks are written in place to a .<name>.PARTIAL file and atomically renamed on completion, so a downloader can even read the file while it's still uploading ("race the beam"), and identical content can be deduplicated via symlink or reflink instead of stored twice.

Architecturally it's a hub-and-workers design: one SvcHub process owns the shared resources (config/auth, the SQLite file index, thumbnail generation, the listening sockets), while one worker process per CPU core — each running its own HttpSrv and thread pool — handles the actual HTTP traffic. Workers talk to the hub through a tiny homemade RPC over multiprocessing.Queue (dotted-path dispatch, serialized exceptions), which sidesteps Python's GIL to get genuinely parallel request handling while keeping the code written as if it were single-process. Its stated philosophy is "inverse unix philosophy — do all the things, and do an okay job," and unlike Nextcloud or Seafile it serves files as-is from your existing folders rather than importing them into a database.

See Copyparty for the architecture deep-dive.