Issue description

The original implementation of long-running Server-Sent Events (SSE) had an issue where the connection would break after a JWT token expired. Clerk.com’s default JWT tokens have a 60-second expiration. This caused a 403 Forbidden error when the backend API and LLM communication exceeded this time, leading to a permanent failure and a broken user experience.

Fix description

See file product.tsx in this folder for the fix.

This fix introduces robust token refresh and connection management logic to prevent session failures. The updated process seamlessly handles expired tokens by automatically re-establishing the SSE connection with a new JWT, ensuring an uninterrupted user experience.

Enhancements include::

1. Error Handling: The code now specifically detects 403 Forbidden errors in the onopen and onerror callbacks.
2. Automatic Reconnection: Upon a 403 error, the system automatically calls connectWithFreshToken() to obtain a new JWT and reconnect.
3. Clean Connection Management: Uses AbortController to gracefully terminate the existing connection before initiating a new one.
4. Concurrency Control: isConnecting flag prevents multiple, simultaneous reconnection attempts.
5. Token Refresh: Each reconnection cycle fetches a new, valid JWT using getToken().

Handling token expiration flow:

Token expires → 403 error → Detect in onopen/onerror → Abort current connection → Get fresh token → Reconnect

This ensures seamless user experience even during extended sessions where tokens expire.