How to use Flask-SocketIO to implement real-time communication applications

Introduction:
In Web applications, real-time communication is a very important function, which allows users to exchange information in real time, or in real time Receive data pushed by the server. Flask-SocketIO is a plug-in based on the Flask framework, which provides the ability to use WebSocket to achieve real-time communication. This article will introduce how to use Flask-SocketIO to implement a simple real-time communication application.

Preparation work:
First, we need to install the Flask-SocketIO plug-in. It can be installed through the following command:

pip install flask-socketio

In addition, we also need to install the Socket.IO JavaScript library for real-time communication on the front end. It can be installed through the following command:

npm install socket.io-client

When these preparations are completed, we can start writing code.

Code example:
The following is a simple Flask-SocketIO real-time communication application code example:

1. Introduce the necessary libraries and modules

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

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2. Create Flask application and configure

   app = Flask(__name__)
   app.config['SECRET_KEY'] = 'secret!'
   socketio = SocketIO(app)

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3. Define routing and event handling functions

   @app.route('/')
   def index():
    return render_template('index.html')
   
   @socketio.on('message')
   def handle_message(message):
    print('received message: ' + message)
    emit('response', {'data': 'Server response'})
   
   @socketio.on('connect')
   def handle_connect():
    print('client connected')
   
   @socketio.on('disconnect')
   def handle_disconnect():
    print('client disconnected')

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4. Create front-end HTML file
   Create a file named index.html in the project root directory and add the following code:

   
   
   
    
    
    
   
   
   
    
   Real-time Communication
    
    Send
    
   
   
    
   
   

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5. Start the application
   Add the following code to the application's entry file to start the application ：

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

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   After running the application, visit http://localhost:5000 in the browser, and you will see a simple real-time communication application interface. Enter a message in the message input box and click the send button to realize the function of sending and receiving messages in real time.

   Summary:
   This article introduces how to use Flask-SocketIO to implement real-time communication applications. Through the Flask-SocketIO plug-in, we can easily and quickly build a real-time communication application to realize real-time message transmission between the server and the client. I hope this article can help you understand how to use Flask-SocketIO to implement real-time communication applications.

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