Medplum

// SPDX-FileCopyrightText: Copyright Orangebot, Inc. and Medplum contributors // SPDX-License-Identifier: Apache-2.0 import type { FhircastConnection, FhircastMessageEvent, FhircastMessagePayload, SubscriptionRequest, } from '@medplum/core'; import { useMedplum } from '@medplum/react'; import { useEffect, useRef, useState } from 'react'; type ConnectionStatus = 'IDLE' | 'CONNECTING' | 'CONNECTED' | 'DISCONNECTING' | 'DISCONNECTED' | 'UNSUBSCRIBED'; type WebSocketHandlerProps = { readonly clientId: string; readonly onMessage: (message: FhircastMessagePayload) => void; readonly subRequest?: SubscriptionRequest; readonly onStatusChange?: (status: ConnectionStatus) => void; }; export default function ConnectionHandler(props: WebSocketHandlerProps): null { const medplum = useMedplum(); const { subRequest, onMessage, onStatusChange } = props; const [connectionStatus, setConnectionStatus] = useState<ConnectionStatus>('IDLE'); const connectionRef = useRef<FhircastConnection>(undefined); const onMessageRef = useRef(onMessage); useEffect(() => { onMessageRef.current = onMessage; }, [onMessage]); useEffect(() => { if (onStatusChange) { onStatusChange(connectionStatus); } }, [onStatusChange, connectionStatus]); useEffect(() => { if (connectionRef.current?.subRequest.endpoint === subRequest?.endpoint) { return; } // If there's an existing subscription at a different endpoint, disconnect and unsub... if (connectionRef.current) { connectionRef.current.disconnect(); medplum .fhircastUnsubscribe(connectionRef.current.subRequest) .then(() => setConnectionStatus((s) => (s === 'CONNECTED' ? s : 'UNSUBSCRIBED'))) .catch((err) => console.error(err)); connectionRef.current = undefined; } if (!subRequest) { return; } const connection = medplum.fhircastConnect(subRequest); const connectHandler = (): void => setConnectionStatus('CONNECTED'); const messageHandler = (event: FhircastMessageEvent): void => onMessageRef.current(event.payload); const disconnectHandler = (): void => { setConnectionStatus('DISCONNECTED'); connection.removeEventListener('connect', connectHandler); connection.removeEventListener('message', messageHandler); connection.removeEventListener('disconnect', disconnectHandler); }; connection.addEventListener('connect', connectHandler); connection.addEventListener('message', messageHandler); connection.addEventListener('disconnect', disconnectHandler); connectionRef.current = connection; }, [medplum, subRequest]); return null; }