Lifecycle

This document describes the lifecycle of WebSocket connections for both Sentinels and Proctors.

• Sentinel: Frame producer (runs on student machines)
• Proctor: Frame consumer (teacher interface)

Sentinel Lifecycle

Flow

1. Connect to server via WebSocket with Authorization: Bearer <jwt> header
2. Send sentinel.register as the first message
3. Receive server.registration.ack or server.registration.reject
4. If accepted: receive server.set-resolution when the server updates the capture resolution
5. Send sentinel.frame every couple of seconds
6. Connection closes when the sentinel shuts down

Sequence Diagram

Proctor Lifecycle

Flow

1. Connect to server via WebSocket with Authorization: Bearer <jwt> header
2. Send proctor.register as the first message
3. Receive server.registration.ack or server.registration.reject
4. If accepted:
   • Receive server.update-sentinels with the list of available sentinels
   • Send proctor.subscribe or proctor.revoke-subscription as needed
   • Send proctor.set-profile to request HIGH, MEDIUM, or LOW
   • Receive server.frame for subscribed sentinels
5. Connection closes when the proctor shuts down

Sentinel Updates

The server sends server.update-sentinels to the proctor:

• Immediately after successful registration
• Whenever a sentinel connects or disconnects

Sequence Diagram