Build a Command-Line To-Do App With Python and Typer

Building an application to manage your to-do list can be an interesting project when you’re learning a new programming language or trying to take your skills to the next level. In this tutorial, you’ll build a functional to-do application for the command line using Python and Typer, which is a relatively young library for creating powerful command-line interface (CLI) applications in almost no time.

With a project like this, you’ll apply a wide set of core programming skills while building a real-world application with real features and requirements.

In this tutorial, you’ll learn how to:

• Build a functional to-do application with a Typer CLI in Python
• Use Typer to add commands, arguments, and options to your to-do app
• Test your Python to-do application with Typer’s CliRunner and pytest

Additionally, you’ll practice your skills related to processing JSON files by using Python’s json module and managing configuration files with Python’s configparser module. With this knowledge, you’ll be ready to start creating CLI applications right away.

You can download the entire code and all the additional resources for this to-do CLI application by clicking the link below and going to the source_code_final/ directory:

Get Source Code: Click here to get the source code you’ll use to build a to-do app for your command line using Python and Typer.

Demo

In this step-by-step project, you’ll build a command-line interface (CLI) application to manage a to-do list. Your application will provide a CLI based on Typer, a modern and versatile library for creating CLI applications.

Before you get started, check out this demo of how your to-do application will look and work once you get to the end of this tutorial. The first part of the demo shows how to get help on working with the app. It also shows how to initialize and configure the app. The rest of the video demonstrates how to interact with the essential features, such as adding, removing, and listing to-dos:

Nice! The application has a user-friendly CLI that allows you to set up the to-do database. Once there, you can add, remove, and complete to-dos using appropriate commands, arguments, and options. If you ever get stuck, then you can ask for help using the --help option with proper arguments.

Do you feel like kicking off this to-do app project? Cool! In the next section, you’ll plan out how to structure the layout of the project and what tools you’ll use to build it.

Project Overview

When you want to start a new application, you typically start by thinking about how you want the app to work. In this tutorial, you’ll build a to-do app for the command line. You’ll call that application rptodo.

You want your application to have a user-friendly command-line interface that allows your users to interact with the app and manage their to-do lists.

To start off, you want your CLI to provide the following global options:

• -v or --version shows the current version and exits the application.
• --help shows the global help message for the entire application.

You’ll see these same options in many other CLI applications out there. It’s a nice idea to provide them because most users who work with the command line expect to find them in every app.

Regarding managing a to-do list, your application will provide commands to initialize the app, add and remove to-dos, and manage the to-do completion status:

Command	Description
init	Initializes the application’s to-do database
add DESCRIPTION	Adds a new to-do to the database with a description
list	Lists all the to-dos in the database
complete TODO_ID	Completes a to-do by setting it as done using its ID
remove TODO_ID	Removes a to-do from the database using its ID
clear	Removes all the to-dos by clearing the database

These commands provide all the functionality you need to turn your to-do application into a minimum viable product (MVP) so that you can publish it to PyPI or the platform of your choice and start getting feedback from your users.

To provide all these features in your to-do application, you’ll need to complete a few tasks:

1. Build a command-line interface capable of taking and processing commands, options, and arguments
2. Select an appropriate data type to represent your to-dos
3. Implement a way to persistently store your to-do list
4. Define a way to connect that user interface with the to-do data

These tasks relate well to what is known as the Model-View-Controller design, which is an architectural pattern. In this pattern, the model takes care of the data, the view deals with the user interface, and the controller connects both ends to make the application work.

Read the full article at https://realpython.com/python-typer-cli/ »

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