Socket.io is used as the underlying protocol for client server communication. This allows the event handlers in the code to be somewhat separate from the connection management - so brief connection interruptions are recoverable.

There are 3 main server side event handlers:

connect - Invoked when a new connection to the server is established. (This may be via http or WebSocket)
oh_user_action - Invoked when a connected client sends an event (such as a prompt for the Agent) - this is distinct from the oh_event sent from the server to the client.
disconnect - Invoked when a connected client disconnects from the server.

Disconnect

The (manager)[manager.py] manages connections and sessions. Each session may have zero or more connections associated with it. When a session no longer has any connections associated with it, after a set amount of time (determined by config.sandbox.close_delay), the session and runtime are passivated (So will need to be rehydrated to continue.)