Build a Site Connectivity Checker in Python


Building a site connectivity checker in Python is an interesting project to level up your skills. With this project, you’ll integrate knowledge related to handling HTTP requests, creating command-line interfaces (CLI), and organizing your application’s code using common Python project layout practices.

By building this project, you’ll learn how Python’s asynchronous features can help you deal with multiple HTTP requests efficiently.

In this tutorial, you’ll learn how to:

Create command-line interfaces (CLI) using Python’s argparse
Check if a website is online using Python’s http.client from the standard library
Implement synchronous checks for multiple websites
Check if a website is online using the aiohttp third-party library
Implement asynchronous checks for multiple websites

To get the most out of this project, you need to know the basics of handling HTTP requests and using argparse to create CLIs. You should also be familiar with the asyncio module and the async and await keywords.

But don’t worry! The topics throughout the tutorial will be introduced in a step-by-step fashion so that you can grasp them as you go. Additionally, you can download the complete source code and other resources for this project by clicking the link below:

Get Source Code: Click here to get the source code you’ll use to build your site connectivity checker app.

Demo: A Site Connectivity Checker

In this step-by-step project, you’ll build an application that checks if one or more websites are online at a given moment. The app will take a list of target URLs at the command line and check them for connectivity either synchronously or asynchronously. The following video shows how the app works:

Your site connectivity checker can take one or more URLs at the command line. Then it creates an internal list of target URLs and checks them for connectivity by issuing HTTP requests and processing the corresponding responses.

Using the -a or –asynchronous option makes the application perform the connectivity checks asynchronously, potentially resulting in lower execution times, especially when you’re processing a long list of websites.

Project Overview

Your website connectivity checker app will provide a few options through a minimal command-line interface (CLI). Here’s a summary of these options:

-u or –urls allows you to provide one or more target URLs at the comment line.
-f or –input-file allows you to supply a file containing a list of URLs to check.
-a or –asynchronous allows you to run the connectivity checks asynchronously.

By default, your application will run the connectivity checks synchronously. In other words, the app will perform the checks one after another.

With the -a or –asynchronous option, you can modify this behavior and make the app run the connectivity checks concurrently. To do this, you’ll take advantage of Python’s asynchronous features and the aiohttp third-party library.

Running asynchronous checks can make your website connectivity checker faster and more efficient, especially when you have a long list of URLs to check.

Internally, your application will use the standard-library http.client module to create a connection to the target website. Once you have a connection, then you can make an HTTP request to the website, which will hopefully react with an appropriate response. If the request is successful, then you’ll know that the site is online. Otherwise, you’ll know that the site is offline.

To display the result of every connectivity check on your screen, you’ll provide your app with a nicely formatted output that will make the app appealing to your users.


The project that you’ll build in this tutorial will require familiarity with general Python programming. Additionally, it’ll require basic knowledge of the following topics:

Handling exceptions in Python
Working with files, the with statement, and the pathlib module
Handling HTTP requests with standard-library or third-party tools
Creating CLI applications with the argparse module
Using Python’s asynchronous features

Knowing the basics of the aiohttp third-party library would also be a plus but not a requirement. However, if you don’t have all this knowledge yet, then that’s okay! You might learn more by going ahead and giving the project a shot. You can always stop and review the resources linked here if you get stuck.

With this short overview of your website connectivity checker project and the prerequisites, you’re almost ready to start Pythoning and having fun while coding. But first, you need to create a suitable working environment and set up your project’s layout.

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