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FastAPI 学习之路（五十二）WebSockets(八)接受/发送json格式消息

news 来源：原创 2024/9/21 14:49:05

前面我们发送的大多数都是text类型的消息，对于text消息来说，后端处理出来要麻烦的多，那么我们可以不可以传递json格式的数据，对于前后端来说都比较友好，答案是肯定的，我们需要做下处理。

首先，我们在websocket管理器中增加处理json格式消息的方法：

from typing import List, Dictfrom starlette.websockets import WebSocketclass ConnectionManager:def __init__(self):"""存放链接"""self.active_connections: List[Dict[str, WebSocket]] = []async def connect(self, user: str, ws: WebSocket):"""链接"""await ws.accept()self.active_connections.append({"user": user, "ws": ws})async def disconnect(self, user: str, ws: WebSocket):"""断开链接，移除"""self.active_connections.remove({"user": user, "ws": ws})@staticmethodasync def send_personal_message(message: str, ws: WebSocket):"""发送所有人消息"""await ws.send_text(message)async def send_other_message(self, message: dict, user: str):"""发送个人消息"""for coon in self.active_connections:if coon["user"] == user:await coon["ws"].send_json(message)async def broadcast(self, data: str):"""广播"""for conn in self.active_connections:await conn["ws"].send_text(data)async def broadcast_json(self, data: dict):"""广播json数据"""for conn in self.active_connections:await conn["ws"].send_json(data)

接口中如何接收json数据呢，新增接口如下：

@app.websocket("/ws/json/{user}")
async def websocket_json_data(websocket: WebSocket,user: str,cookie_or_token: str = Depends(get_cookie_or_token)
):"""发送接收json数据（前面一对一接口其实就是发送的json数据）"""await ws_manager.connect(user, websocket)try:while True:data = await websocket.receive_json()send_user = data["username"]if send_user:await ws_manager.send_other_message(data, send_user)else:await ws_manager.broadcast_json(data)except WebSocketDisconnect as e:await ws_manager.disconnect(user, websocket)

前端也要相对应的修改：

<!DOCTYPE html>
<html>
<head><title>Chat</title>
</head>
<body>
<h1>WebSocket 聊天</h1>
<form action="" onsubmit="sendMessage(event)"><input type="text" id="messageText" autocomplete="off"/><input type="text" id="username" autocomplete="off"/><button>Send</button>
</form>
<button onclick="logout()">退出</button>
<ul id='messages'>
</ul>
<script>var  token=window.localStorage.getItem("token")if (token==null ){window.location.href="/login"}var ws = new WebSocket("ws://localhost:8000/ws/json/"+token+"?token="+token);ws.onmessage = function (event) {var messages = document.getElementById('messages')var message = document.createElement('li')let receiveJson = JSON.parse(event.data);console.log(receiveJson)var content = document.createTextNode(receiveJson.username+"说:"+receiveJson.messageText)message.appendChild(content)messages.appendChild(message)};function sendMessage(event) {var input = document.getElementById("messageText")var username = document.getElementById("username")let message = {messageText: input.value, username:username.value};let messageJson = JSON.stringify(message);ws.send(messageJson);// input.value = ''event.preventDefault()}function logout() {window.localStorage.removeItem("token")window.location.href='/login'}
</script></body></html>

部署看效果，因为发送给后端的数据格式是前端拼的json，所以页面上只需要填文本即可：