The problem: if you publish any document as PDF, in print, etc. and the text contains URLs, there is a chance that one day those URLs won't work anymore. There's nothing to do about that, it happens.

Luckily, this is a solved problem. The solution is to link to a stable and trustworthy website, that is, one that you maintain and host (of course, you're trustworthy!). Then in the document you link to that website, and the website redirects visitors to the actual location.

An example: my book contains a link to https://enjoy.gitstore.app/repositories/matthiasnoback/read-with-the-author. When I moved that repository to a new organization on GitHub, this link resulted in a 404 Page not found error. The proper URL is now https://enjoy.gitstore.app/repositories/read-with-the-author/read-with-the-author. Chris from Gitstore was able to save the day by setting up a redirect on their site, but I wanted to make sure this kind of problem would never be a problem for me again.

In the Epilogue of the Object Design Style Guide, I started happily outlining some of the architectural patterns I've been using for several years now. I wanted to give some kind of an overview of how the overall design of your application would improve if you apply the object-design rules in that book. I soon realized that an Epilogue was not enough to cover all the details, or to communicate the ideas in such a way that they would be applicable in everyday projects. And so a new book project began...

When Symfony2 was created I first learned about the functional test, which is an interesting type of test where everything about your application is as real as possible. Just like with an integration or end-to-end test. One big difference: the test runner exercises the application's front controller programmatically, instead of through a web server. This means that the input for the test is a Request object, not an actual HTTP message.