Polling Fallback

When Polling Activates

Polling activates automatically when:

• The initial WebSocket connection fails (e.g., WebSockets are blocked by a proxy)
• Reconnection attempts exhaust all retry delays (1s, 2s, 5s, 10s)
• The browser network monitor detects the WebSocket was closed with a non-recoverable error

useExecutionPolling

// useExecutionPolling.ts
export function useExecutionPolling(executionId: string, enabled: boolean) {
  useEffect(() => {
    if (!enabled) return;

    const interval = setInterval(async () => {
      const status = await fetch(
        `/api/v1/process-engine/executions/${executionId}/status`
      ).then(r => r.json());

      // Update store with polled status
      updateStoreFromPolledStatus(status);

      // Stop polling when execution is terminal
      if (['completed', 'failed', 'cancelled'].includes(status.status)) {
        clearInterval(interval);
      }
    }, 2000);

    return () => clearInterval(interval);
  }, [executionId, enabled]);
}

Polling Limitations vs SignalR