Building a Multiplayer Game with Python

Introduction
Prerequisites
Setup
Creating a Game Server
Building the Game Logic
Creating the Client
Conclusion

Introduction

In this tutorial, we will learn how to build a multiplayer game using Python. We will create a game server that handles multiple player connections and allows them to interact with each other in real-time. By the end of this tutorial, you will have a basic understanding of creating a multiplayer game and be able to expand upon it to build more complex games.

Prerequisites

To follow along with this tutorial, you should have a basic understanding of Python programming. Familiarity with socket programming and basic web development concepts will be helpful but not required.

Setup

Before we start building our game, we need to set up our development environment. Follow these steps to get started:

Install Python: If you don’t have Python installed, download and install the latest version from the official Python website.
Set up a virtual environment: Open your command prompt or terminal, navigate to your project directory, and create a new virtual environment by running the following command:
```
python -m venv myenv
```
Activate the virtual environment: Once the virtual environment is created, activate it by running the appropriate command for your operating system:
- For Windows:
```
myenv\Scripts\activate
```
- For Unix/Linux:
```
source myenv/bin/activate
```
Install required packages: Within the virtual environment, install the necessary packages by running the following command:
```
pip install flask
```
We are now ready to start building our multiplayer game!

Creating a Game Server

To create a multiplayer game, we need a game server that will handle multiple player connections and provide the game logic. Follow these steps to create a simple game server using Flask:

Create a new Python file called game_server.py.

Import the necessary modules:

from flask import Flask, render_template, request, jsonify
import random

Initialize the Flask application:
```
app = Flask(__name__)
```

Define the route for the game lobby:

@app.route('/')
def lobby():
    return render_template('lobby.html')

Start the server:
```
if __name__ == '__main__':
    app.run(debug=True)
```
This sets up a basic game server using Flask. The lobby route will render a template called lobby.html that will serve as the main lobby page for the game.

Building the Game Logic

Now that we have our game server set up, let’s implement the game logic. For this tutorial, we will create a simple guessing game where players try to guess a randomly generated number.

Create a new Python file called game_logic.py.

Implement the game logic:

import random

class GuessingGame:
    def __init__(self):
        self.secret_number = None

    def start_game(self):
        self.secret_number = random.randint(1, 100)

    def guess_number(self, number):
        if number < self.secret_number:
            return 'Higher'
        elif number > self.secret_number:
            return 'Lower'
        else:
            return 'Correct'

This sets up a GuessingGame class with methods to start the game and check if a player’s guess is correct.

Creating the Client

Now that we have our game server and game logic, we need to create a client that will allow players to connect to the server and interact with the game. We will create a simple HTML and JavaScript-based client.

Create a new directory called static within your project directory.

Create a new HTML file called index.html inside the static directory and add the following HTML code:

<!DOCTYPE html>
<html>
<head>
    <title>Guessing Game</title>
    <script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
</head>
<body>
    <h1>Guessing Game</h1>
    <h3 id="message"></h3>
    <input type="number" id="guess">
    <button onclick="submitGuess()">Submit</button>

    <script>
        var socket = new WebSocket('ws://localhost:5000/ws');

        socket.onmessage = function (event) {
            $('#message').text(event.data);
        };

        function submitGuess() {
            var guess = $('#guess').val();
            socket.send(guess);
        }
    </script>
</body>
</html>

Create a new Python file called game_client.py.

Implement the client-server communication:

from flask import Flask, render_template, request, jsonify
from flask_socketio import SocketIO

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

@app.route('/')
def index():
    return app.send_static_file('index.html')

@socketio.on('message')
def handle_message(message):
    guess = int(message)
    result = game.guess_number(guess)
    socketio.send(result)

if __name__ == '__main__':
    game = GuessingGame()
    game.start_game()
    socketio.run(app)

This sets up the client-side HTML and JavaScript and creates a WebSocket connection to the game server. The client sends the player’s guess to the server and receives the result.

Conclusion

In this tutorial, we have learned how to build a simple multiplayer game using Python. We created a game server using Flask and implemented the game logic. We also created a client using HTML and JavaScript to allow players to interact with the game.

You can further enhance this game by adding features such as multiple game rooms, player authentication, and real-time chat functionality. Use this tutorial as a starting point to explore more complex multiplayer game development using Python.

Remember to experiment and have fun while building your own multiplayer games!

Published: 20 July 2019