WebSocket endpoint creation in FastAPI - Cheat Sheet & Quick Revision

Recall & Review

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What is a WebSocket endpoint in FastAPI?

A WebSocket endpoint in FastAPI is a special route that allows real-time, two-way communication between the client and server using the WebSocket protocol.

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How do you accept a WebSocket connection in FastAPI?

You accept a WebSocket connection by calling the await websocket.accept() method inside the WebSocket endpoint function.

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Which FastAPI class is used to handle WebSocket connections?

The <code>WebSocket</code> class from <code>fastapi</code> is used to handle WebSocket connections, allowing sending and receiving messages.

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What method do you use to receive a message from a WebSocket client in FastAPI?

Use await websocket.receive_text() to receive a text message from the client.

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How do you send a message back to the WebSocket client in FastAPI?

Use await websocket.send_text(message) to send a text message back to the client.

Which decorator is used to create a WebSocket endpoint in FastAPI?

A @app.websocket

B @app.get

C @app.post

D @app.route

The @app.websocket decorator defines a WebSocket endpoint in FastAPI.

What must you do first inside a WebSocket endpoint function to start communication?

A Call websocket.accept()

B Call websocket.close()

C Call websocket.send_text()

D Call websocket.receive_text()

You must call await websocket.accept() to accept the connection before sending or receiving messages.

How do you receive a text message from the client in FastAPI WebSocket?

A await websocket.accept()

B await websocket.send_text()

C await websocket.close()

D await websocket.receive_text()

Use await websocket.receive_text() to get a text message from the client.

Which protocol does FastAPI use for WebSocket communication?

A FTP

B HTTP/1.1

C WebSocket protocol

D SMTP

FastAPI uses the WebSocket protocol for real-time two-way communication.

What happens if you don't call websocket.accept() in a FastAPI WebSocket endpoint?

A The server crashes

B The connection is not established

C Messages can still be sent and received

D The connection closes immediately

Without calling websocket.accept(), the WebSocket connection is not established and communication cannot start.

Explain step-by-step how to create a WebSocket endpoint in FastAPI that echoes messages back to the client.

Think about accepting connection, receiving, and sending messages.

Describe the role of the WebSocket class in FastAPI and how it helps in real-time communication.

Focus on what the WebSocket object lets you do inside the endpoint.