FastAPI WebSocket 簡單演示
下午沒事看了看WebSocket，感覺這個挺好玩的，比寫CRUD有意思。就復制了官網的demo演示看了看。
官方文檔 https://fastapi.tiangolo.com/advanced/websockets/
效果
WebSocket 服務
使用Python FastAPI框架官網demo
from typing import List
from fastapi import FastAPI, WebSocket, WebSocketDisconnect
app = FastAPI()
class ConnectionManager:
def __init__(self):
# 存放激活的ws連接對象
self.active_connections: List[WebSocket] = []
async def connect(self, ws: WebSocket):
# 等待連接
await ws.accept()
# 存儲ws連接對象
self.active_connections.append(ws)
def disconnect(self, ws: WebSocket):
# 關閉時 移除ws對象
self.active_connections.remove(ws)
@staticmethod
async def send_personal_message(message: str, ws: WebSocket):
# 發送個人消息
await ws.send_text(message)
async def broadcast(self, message: str):
# 廣播消息
for connection in self.active_connections:
await connection.send_text(message)
manager = ConnectionManager()
@app.websocket("/ws/{user}")
async def websocket_endpoint(websocket: WebSocket, user: str):
await manager.connect(websocket)
await manager.broadcast(f"用戶{user}進入聊天室")
try:
while True:
data = await websocket.receive_text()
await manager.send_personal_message(f"你說了: {data}", websocket)
await manager.broadcast(f"用戶:{user} 說: {data}")
except WebSocketDisconnect:
manager.disconnect(websocket)
await manager.broadcast(f"用戶-{user}-離開")
if __name__ == "__main__":
import uvicorn
# 官方推薦是用命令后啟動 uvicorn main:app --host=127.0.0.1 --port=8010 --reload
uvicorn.run(app='main:app', host="127.0.0.1", port=8010, reload=True, debug=True)
前端
前端只是簡單使用演示, 沒有對連接做鑒權處理。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>聊天1</title>
</head>
<body>
<h1>User1 Chat</h1>
<form action="" onsubmit="sendMessage(event)">
<input type="text" id="messageText" autocomplete="off"/>
<button>Send</button>
</form>
<ul id='messages'>
</ul>
<script>
var ws = new WebSocket("ws://127.0.0.1:8010/ws/user1");
ws.onmessage = function(event) {
var messages = document.getElementById('messages')
var message = document.createElement('li')
var content = document.createTextNode(event.data)
message.appendChild(content)
messages.appendChild(message)
};
function sendMessage(event) {
var input = document.getElementById("messageText")
ws.send(input.value)
input.value = ''
event.preventDefault()
}
</script>
</body>
</html>
用戶2， 和上面的用戶1沒什么區別，只是連接WebSocket 參數變化區分，
其他地方一樣，就是url參數變化了。
<script>
var ws = new WebSocket("ws://127.0.0.1:8010/ws/user2");
ws.onmessage = function(event) {
var messages = document.getElementById('messages')
var message = document.createElement('li')
var content = document.createTextNode(event.data)
message.appendChild(content)
messages.appendChild(message)
};
function sendMessage(event) {
var input = document.getElementById("messageText")
ws.send(input.value)
input.value = ''
event.preventDefault()
}
</script>
總結
WebSocket使用還是很簡單的，但是封裝鑒權，前端斷線重連等等操作還是很耗時的。