Implement Message Acknowledgements
Socket.IO passes an acknowledgement callback to the server when the client provides one.
We can use this callback to return a success or failure response.
Update the server-side message handler to validate the payload and respond through the acknowledgement callback.
Server Acknowledgement
socket.on('chat:send', (payload, acknowledge) => {
if (!validateChatMessage(payload)) {
acknowledge?.({
success: false,
error: 'Invalid message payload'
});
return;
}
const chatMessage = {
username: payload.username.trim(),
message: payload.message.trim(),
timestamp: new Date().toISOString()
};
io.emit('chat:message', chatMessage);
acknowledge?.({
success: true,
message: 'Message accepted by server'
});
});The server invokes the acknowledgement callback after validating and broadcasting the message. Optional chaining allows the handler to work even when the client does not request an acknowledgement.
Key Takeaways
Acknowledgement callbacks are supplied by the sender.
The receiver invokes the callback to return a result.
Use structured responses to communicate success and failure.