In this chapter, we will be connecting our chat application to a web service written using the flask microframework. We will learn how to write a small flask application that handles HTTP requests and updates a sqlite database in the process. We will then take advantage of the requests module to allow for easy communication between a graphical application and a web service.

In this chapter, we will cover the following topics:

• Using the flask module to create a web service
• Handling both GET and POST requests in flask
• Using a sqlite database for persistent storage
• Making HTTP requests using the requests module

Let's begin by having a look at flask. We'll take a tour of what it is and how it works before using it to create a web service that can handle which users exist in our chat application and who is allowed to talk to whom.