Cum să implementezi WebSocket într-un API Python cu FastAPI

from fastapi import FastAPI, WebSocket, WebSocketDisconnect
from typing import List

app = FastAPI()

class ConnectionManager:
    def __init__(self):
        self.active_connections: List[WebSocket] = []

    async def connect(self, websocket: WebSocket):
        await websocket.accept()
        self.active_connections.append(websocket)

    def disconnect(self, websocket: WebSocket):
        self.active_connections.remove(websocket)

    async def send_personal(self, message: str, websocket: WebSocket):
        await websocket.send_text(message)

    async def broadcast(self, message: str):
        for connection in self.active_connections:
            await connection.send_text(message)

manager = ConnectionManager()

@app.websocket("/ws/{client_id}")
async def websocket_endpoint(websocket: WebSocket, client_id: str):
    await manager.connect(websocket)
    try:
        while True:
            data = await websocket.receive_text()
            await manager.send_personal(
                f"Primit: {data}", websocket
            )
            await manager.broadcast(
                f"Client {client_id} a trimis: {data}"
            )
    except WebSocketDisconnect:
        manager.disconnect(websocket)
        await manager.broadcast(
            f"Client {client_id} s-a deconectat"
        )

const ws = new WebSocket("ws://localhost:8000/ws/user1");

ws.onopen = () => {
    console.log("Conexiune WebSocket stabilită");
    ws.send("Salut server!");
};

ws.onmessage = (event) => {
    console.log("Mesaj primit:", event.data);
};

ws.onclose = () => {
    console.log("Conexiunea s-a închis");
};

pip install flask-socketio

from flask import Flask, render_template
from flask_socketio import SocketIO, emit

app = Flask(__name__)
socketio = SocketIO(app, cors_allowed_origins="*")

@socketio.on("conectare")
def handle_conectare():
    emit("mesaj", {"data": "Bine ai venit!"})

@socketio.on("mesaj_client")
def handle_mesaj(data):
    print(f"Primit: {data}")
    emit("raspuns", {"data": f"Ai spus: {data['text']}"})

if __name__ == "__main__":
    socketio.run(app, debug=True)

from fastapi import WebSocket

rooms = {}

@app.websocket("/ws/chat/{room_id}")
async def chat_room(websocket: WebSocket, room_id: str):
    await websocket.accept()
    if room_id not in rooms:
        rooms[room_id] = []
    rooms[room_id].append(websocket)
    try:
        while True:
            data = await websocket.receive_text()
            for client in rooms[room_id]:
                if client != websocket:
                    await client.send_text(data)
    except WebSocketDisconnect:
        rooms[room_id].remove(<a href="/apis/websocket/">WebSocket</a>)

function conectareWebSocket() {
    const ws = new WebSocket("ws://localhost:8000/ws");

    ws.onclose = () => {
        setTimeout(conectareWebSocket, 3000);
    };

    // Ping la fiecare 30 de secunde
    setInterval(() => {
        if (ws.readyState === <a href="/apis/websocket/">Websocket</a>.OPEN) {
            ws.send(JSON.stringify({ tip: "ping" }));
        }
    }, 30000);
}