Modernizing Legacy Applications in PHP

Chapter 17. Conclusion

Let us think back on our progress.

We started out with a spaghetti mess of a legacy application. The entire application was based in the document root, and users browsed directly to page scripts. It used an include-oriented architecture, where merely including a file caused logic to be executed. Global variables were scattered everywhere, which made debugging difficult to impossible. There were no tests of any sort, much less unit tests, so every change raised the possibility of breaking something else. There was no clear separation of model, view, and controller layers. SQL statements were embedded throughout our code, and domain logic was mixed in with presentation and action logic.

Now, after a great deal of effort, dedication, ...