AJAX vs SSE
- SSE: the client establishes a persistent and long-term connection with the server. The server uses this connection to send data to a client.
- AJAX: the client repeatedly polls (or requests) a server for data. The client makes a request and waits for the server to respond with data. If no data is available, an empty response is returned.
How to Choose?
- Use SSE: For real-time data streams where constant updates are crucial (e.g., live chat, stock tickers).
- Use AJAX: For scenarios requiring two-way communication, or data exchange beyond real-time updates (e.g., shopping carts, form submissions).
Troubleshooting
Method is not allowed(405)
// code inside web page <script> tag
const source = new EventSource("/sse");
Running the above code get the following error message(From browser developer > Source):
Failed to load resource: The server response with a status of 405(Method Not Allowed)
Solution:
EventSource() is a GET method, if the server only has POST method you’ll get this error,
even if the link is right. The server must respond to the GET method.