In this chapter, we have learned a lot about some non-Tkinter technologies which can be used to supplement a GUI application.

We learned how to set up a very basic web service using the flask module. We know how to create URL routes using the app.route decorator and have learned how to handle both GET and POST requests. We also had an introduction to JSON as a portable way of sending information back to a client.

The SQLite database technology has been explored and we know how to create databases in our filesystem. We have practiced querying them and seen some basic SQL statement syntax. We have learned both how to put information into a database table and how to retrieve it again. We also saw that we can use the Row class to get information as a dictionary, which is often preferable to the standard tuple responses.

We have looked at sending GET and POST requests using the requests module. We have seen how to send data over to an endpoint, as well as parse the response with either r.text or r.json(). We have also created a generic class wrapper around this module which makes code from other classes much more succinct and readable.

After all of that knowledge was practiced, we then utilized it to get both our FriendsList and ChatWindow classes communicating with the new web service via requests, which called a flask endpoint to communicate with an sqlite3 database.

Our FriendsList class now knows what users exist on the server and the ChatWindow is able to keep and display a history of sent messages between two users.

In the next chapter, we will polish off our chat application by getting messages to update in the background while the user has the window open. We will also sort out the ability for each account to have its own avatar image and block other users from contacting them.