[Solved] What will be the output when the following Flask-SocketIO event handler receives a 'ping' event?@socketio.on('ping') def handle_ping(): socketio.emit('pong') | Flask

Flask - WebSocket and Real-Time

What will be the output when the following Flask-SocketIO event handler receives a 'ping' event?

@socketio.on('ping')
def handle_ping():
    socketio.emit('pong')

ANothing happens because 'pong' event is not handled

BThe server sends a 'pong' event back to the client

CThe server raises an error because no data parameter is defined

DThe server sends a 'ping' event back to the client

Step-by-Step Solution

Solution:

Step 1: Analyze the event handler code
The handler listens for 'ping' events and calls socketio.emit('pong') to send a 'pong' event.
Step 2: Understand the effect of emit without data
Emitting 'pong' without data sends the event to the client. No error occurs because data parameter is optional.
Final Answer:
The server sends a 'pong' event back to the client -> Option B
Quick Check:
Emit sends event to client = 'pong' sent [OK]

Quick Trick: Emit sends events to clients; data parameter is optional [OK]

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What will be the output when the following Flask-SocketIO event handler receives a 'ping' event?