In most major projects, whether they are web applications or other types of programs, developers spend some time building up "infrastructure" before beginning development on the unique features of the application. This infrastructure ranges from setting up source code control systems to bug tracking databases to building up classes and libraries of code to manage such common problems and tasks as error handling, session management, and database connections.
This chapter has proposed solutions and infrastructure code to use for many of these tasks, and it has shown a strategy via which to manage them. It would be extremely presumptuous to suggest that these are the only solutions to these problems or even the "best" solutions to them. This chapter merely posits that they have proven quite effective in the web applications demonstrated in this book (among others) and should at the very least provide you with a set of ideas from which to develop your own strategies and libraries in your web applications.
In the next chapter, we will look at our first web application, a simple appointment management system.