19 – Cleaning Up When the Server Shuts Down

A WebSocket app that keeps a little state per connection (the messages it received) and saves it when the connection ends:

• Tells a server shutdown (code 1012, reason server_shutdown) from a client leaving.
• Saves each session asynchronously (a 0.2 s sleep stands in for a database or remote service).
• Prints a summary in lifespan.shutdown, which the server sends only after every connection's application has returned -- so every session is saved before the process exits.

Quick Start

1. Start the server:

pagi-server --app examples/19-shutdown-cleanup/app.pl --port 5000

2. Connect two clients and type a few lines in each:

websocat ws://127.0.0.1:5000/

Each line is answered with noted: N.

3. Stop the server with Ctrl+C. The log shows each session ending with server shutdown, code 1012, then saved N message(s) for each, and only then shutdown: 2 session(s) saved.

Close a client yourself instead and its session ends with client left.

Spec References

• Shutdown order – PAGI::Spec::Lifespan ("Shutdown - receive event")
• WebSocket close on shutdown – PAGI::Spec::Www ("Disconnect - receive event")