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

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：

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from typing import List, Dict

from starlette.websockets import WebSocket


class 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})

    @staticmethod
    async 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：

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@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：

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<!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：