How to use push notifications in FastAPI to update data in real time-Python Tutorial-php.cn

How to use push notifications in FastAPI to update data in real time

王林

Release： 2023-07-29 18:09:14

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How to use push notifications in FastAPI to update data in real time

Introduction:
With the continuous development of the Internet, real-time data updates are becoming more and more important. For example, in application scenarios such as real-time trading, real-time monitoring, and real-time gaming, we need to update data in a timely manner to provide the most accurate information and the best user experience. FastAPI is a modern Python-based web framework that provides a simple and efficient way to build high-performance web applications. This article will introduce how to use FastAPI to implement push notifications to update data in real time.

Step 1: Preparation
First, we need to install FastAPI and the corresponding dependent libraries. It can be installed using the following command:

pip install fastapi
pip install uvicorn

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Next, we need to create a Python file and name it main.py. We will write our FastAPI application in it.

Step 2: Write push notification logic
We will use WebSocket to implement the push notification function. WebSocket is a protocol that enables full-duplex communication between client and server. In FastAPI, we can use the third-party library fastapi-websocket to easily add WebSocket support to our application. The library can be installed using the following command:

pip install fastapi-websocket

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In main.py, we first import the required modules:

from fastapi import FastAPI, WebSocket
from fastapi.responses import HTMLResponse
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates
from fastapi import WebSocket, WebSocketDisconnect

from fastapi_websocket_pubsub import PubSubEndpoint
from fastapi_websocket_pubsub import PubSubWebSocketEndpoint

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Then, we create a FastAPI application Program:

app = FastAPI()
app.mount("/static", StaticFiles(directory="static"), name="static")

templates = Jinja2Templates(directory="templates")

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Next, we need to define the logic of WebSocket. We will create a subclass of WebSocket and implement the push notification function in it:

class NotificationsWebSocket(WebSocketEndpoint):
async def on_receive(self, websocket: WebSocket, data: str):
    # 在这里实现推送通知的逻辑
    # 可以根据需要订阅特定的主题或频道

async def on_connect(self, websocket: WebSocket):
    await websocket.accept()

async def on_disconnect(self, websocket: WebSocket, close_code: int):
    await self.pubsub.unsubscribe(self.room_name, websocket)

app.add_websocket_route("/ws", NotificationsWebSocket)

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In the on_receive method, we can subscribe to specific topics or channels as needed and pass WebSocket Send new data to the client. In FastAPI applications, we can use PubSubEndpoint to manage subscription and publishing logic. The fastapi_websocket_pubsub library can be installed using the following command:

pip install fastapi_websocket_pubsub

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In main.py, we import PubSubEndpoint and create an instance:

from fastapi_websocket_pubsub import PubSubEndpoint

pubsub = PubSubEndpoint()

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Then , we pass the pubsub instance to the subclass of WebSocket in order to use the push notification function:

class NotificationsWebSocket(WebSocketEndpoint):
    async def on_receive(self, websocket: WebSocket, data: str):
        # 在这里实现推送通知的逻辑
        await self.pubsub.publish(self.room_name, data)

    async def on_connect(self, websocket: WebSocket):
        await self.pubsub.subscribe(self.room_name, websocket)
        await websocket.accept()

    async def on_disconnect(self, websocket: WebSocket, close_code: int):
        await self.pubsub.unsubscribe(self.room_name, websocket)

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Step 3: Create a front-end page
We also need to create a front-end page so that users can browse through server to access our application. You can create a file named index.html and place it in a folder named templates. In index.html we can use WebSocket to subscribe to push notifications and update the page when new data is received. Here is a simple example:

<!DOCTYPE html>
<html>
<head>
    <title>Notifications</title>
</head>
<body>
    <h1>Notifications</h1>
    <ul id="messages"></ul>

    <script>
    const socket = new WebSocket("ws://localhost:8000/ws");
    
    socket.onopen = () => {
        console.log("WebSocket connection is open.");
    };
    
    socket.onmessage = (event) => {
        const message = document.createElement("li");
        message.textContent = event.data;
        document.getElementById("messages").appendChild(message);
    };
    
    socket.onclose = () => {
        console.log("WebSocket connection is closed.");
    };
    
    </script>
</body>
</html>

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Step Four: Start the Application
At the end of main.py, we need to add the following code to start the FastAPI application:

if __name__ == "__main__":
    import uvicorn
    uvicorn.run(app, host="0.0.0.0", port=8000)

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Now, we can start our FastAPI application using the following command:

python main.py

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Done! Now, we can view the push notification function by visiting http://localhost:8000 through the browser. When new data is pushed, the page will automatically update to display the latest information.

Conclusion:
This article introduces how to use push notifications in FastAPI to update data in real time. By using WebSocket and PubSubEndpoint libraries, we can easily implement push notification functionality. This method of updating data in real time can be applied to many application scenarios, such as real-time trading, real-time monitoring, and real-time gaming. I hope this article can be helpful to you, and I wish you can use FastAPI to build more efficient and real-time web applications.

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