A persistent two-way connection between the browser and the server is needed for real-time short message exchange. What to choose? WebSocket Server-Sent Events HTTP Long Polling HTTP/2 Server Push

For persistent two-way communication between the browser and the server, especially for exchanging short messages in real-time, WebSocket is the most suitable.

Explanation:

• WebSocket is a protocol that establishes a persistent connection between the client and the server, allowing both parties to send data at any time without the need for repeated requests.
• Server-Sent Events (SSE) is a one-way channel from the server to the client, not suitable for two-way communication.
• HTTP Long Polling simulates a persistent connection through repeated requests, which is less efficient and has higher latency.
• HTTP/2 Server Push allows the server to send resources to the client without a request, but is not intended for two-way message exchange.

Therefore, WebSocket is chosen for real-time two-way communication.