One of the signatures of the Flask framework is its clever use of decorators for common application tasks such as defining routes and error handlers. Decorators give a very concise and readable structure to your code, so much that most Flask extensions and many other Python packages follow the same pattern and expose core parts of their functionality through decorators.

Today I'm starting a series of in-depth posts about different ways in which you can incorporate custom decorators into your Python applications. In this first part I'm going to show you how to create simple decorators that register functions as callbacks for application-specific events.

In this chapter you are going to learn how to install and use MicroPython on your ESP8266 microcontroller board.

If you want to see me and hear me explain everything in this tutorial, I encourage you to purchase the video version from my Courses site. Not only it will make for a better learning experience, but you'll also be supporting my effort in keeping my blog updated with relevant content. Thank you!

Welcome to my MicroPython and the Internet of Things tutorial!

In this first part I want to give you a brief overview of what this tutorial is about, and more importantly, provide you the list of components that you are going to need.

I'm happy to announce a new multi-part tutorial that I will soon begin publishing on this blog and several other platforms. The tutorial is titled MicroPython and the Internet of Things and is a beginner tutorial that will introduce you to the exciting world of microcontrollers and small-form Internet enabled devices.

When you deploy your application on a server, you need to make sure the application runs uninterrupted. If the application crashes, you'd want it to automatically restart, and if the server experiences a power outage, you'd want the application to start immediately once power is restored. Basically what you need is something that keeps an eye on the application and restarts it if it ever finds that it isn't running anymore.

In previous tutorials, I showed you how to implement this using supervisord, which is a third party utility written in Python. Today I'm going to show you a similar solution based on systemd, which is a native component in many Linux distributions including Debian derivatives such as Ubuntu and RedHat derivatives such as Fedora and CentOS.

One of the most rewarding aspects of having a popular course online is that from time to time I get a question that forces me to learn something new. The other day a reader asked me how they can write a database query with an unusual ordering, and I had to stop for a minute (okay, it was more like half an hour) to think about how to do it within the context of a Flask and Flask-SQLAlchemy application. Are you ready to see some advanced SQLAlchemy action?

One of the useful features of my Flask-SocketIO extension is the test client, which allows you to write Socket.IO unit tests. A long time limitation of the test client was that it did not see cookies set by Flask, such as the user session. This complicated writing Socket.IO tests for applications that require authentication, because most authentication mechanisms write something to the user session or a custom cookie. The use case that caused pain to a lot of developers was applications that use Flask-Login combined with Flask-SocketIO. To unit test such an application you had to resort to weird tricks such as mocking the current_user variable.

I recently came up with a solution to this problem, so I'm glad to report that this limitation is now a thing of the past. In this short article I want to show you how to set up your project to take advantage of the new cookie support in the Socket.IO test client.

For many types of applications, at times it is necessary to pause the running of the program until some external condition occurs. You may need to wait until another thread finishes, or maybe until a new file appears in a directory on disk that is being watched.

In these and many other situations you will need to figure out a way to make your script wait, and this isn't as easy as it sounds if you want to do it properly! In this article I'm going to show you a few different ways to wait. I'm going to use Python for all the examples, but the concepts I'm going to present apply to all programming languages.

In this short article and video I want to give you a few tips on setting up a PyCharm project for your Flask application. The idea is to set up a Flask application so that it can be executed, debugged, and tested from inside PyCharm Community Edition, which is fantastic IDE for Python that is completely free to download and use. If you want to see me go through the exercise, watch the video below. Then you can come to the article if you want a quick reference and summary of the steps required.

JSON Web Tokens offer a simple and powerful way to generate tokens for APIs. These tokens carry a payload that is cryptographically signed. While the payload itself is not encrypted, the signature protects it again tampering. In their most common format, a "secret key" is used in the generation and verification of the signature. In this article I'm going to show you a less known mechanism to generate JWTs that have signatures that can be verified without having access to the secret key.