How can I see if there's an available and active network connection in Python?

In Python, to verify if a device has an active network connection, multiple methods can be employed. Here, I will introduce two commonly used approaches:

Method One: Using the socket Library

You can utilize the socket library to establish a connection, for example, by connecting to a common address such as Google's homepage. If the connection succeeds, it confirms an active network connection.

python
import socket

def check_network_connection(host="8.8.8.8", port=53, timeout=3):
    """
    Verify network connectivity
    :param host: The remote IP address to connect to, defaulting to Google's DNS server
    :param port: The port number, defaulting to the DNS service port
    :param timeout: Connection timeout duration
    :return: Boolean value, returning True if the connection succeeds, otherwise False
    """
    try:
        socket.setdefaulttimeout(timeout)
        socket.socket(socket.AF_INET, socket.SOCK_STREAM).connect((host, port))
        return True
    except socket.error as ex:
        print(f"Connection error: {ex}")
        return False

# Example usage
if check_network_connection():
    print("Network connection is active!")
else:
    print("No network connection.")

Method Two: Using the requests Library

Another approach is to use the requests library to attempt accessing a website (e.g., www.google.com). If the request succeeds, the network connection is active.

python
import requests

def check_internet(url='http://www.google.com', timeout=5):
    """
    Verify internet connectivity via HTTP request
    :param url: The URL to test connectivity to, defaulting to Google's homepage
    :param timeout: Request timeout duration
    :return: Boolean value, returning True if the request succeeds, otherwise False
    """
    try:
        response = requests.get(url, timeout=timeout)
        # Verify HTTP response status code is 200
        return response.status_code == 200
    except requests.ConnectionError:
        print("Unable to connect to the internet")
        return False
    except requests.Timeout:
        print("Connection timeout")
        return False
    except requests.RequestException as e:
        print(f"Request error: {e}")
        return False

# Example usage
if check_internet():
    print("Network connection is active!")
else:
    print("No network connection.")

Summary

Both methods have distinct advantages and disadvantages. The socket library approach is more low-level and efficiently verifies network connectivity, while the requests library provides higher-level HTTP operations that enable detailed simulation of network requests, including handling redirects and SSL. Select the appropriate method based on your specific application requirements.