In the first part of this chapter, you familiarized yourself with QNetworkAccessManager. This class is at the heart of your code whenever you want to download or upload files to the internet. After having gone through the different signals that you can use to fetch errors, to get notified about new data or to show the progress, you should now know everything you need on that topic.
The example about the Distance Matrix API depended on your knowledge of QNetworkAccessManager, and it shows you a real-life application case for it. Dealing with JSON as the server's reply format was a summary of Chapter 4, Qt Core Essentials, but it was highly needed since Facebook and Twitter only use JSON to format their network replies.
In the last section, you learned how to set up your own TCP server and clients. This enables you to connect different instances of a game to provide...