Class based views are always better*
In the Django community, there is this long running discussion that juxtaposes view styles that are offered by the web framework. One is a good-old function based style and the other is class based style. I certainly will not settle this discussion by asserting my ideas here but I’ll try to convince you at least.
Now, at some point in the framework, the only way to write views was using the functions. Class-based views were introduced with Django 1.3 along with a migration guide. You can see the generic old-style function views here.
Inspect these views and think about possible drawbacks; you needed endless numbers of function chains with long-running parameters, just to implement a generic view with some custom logic. I’m pretty sure everybody acknowledges that class based views brought simplicity to generic views, so I will not dwell on that much. I am also pretty sure everyone will acknowledge that CBV are (obviously): more readable, more scalable and more extendable.
Here are some common assertions made to justify function-based usage, I have provided my responses below.
My logic is so simple! or Generic views just don’t fit my purposes!
If your logic is simple, you better use the most primitive base class View. It’s just a plain wrapper that provides get and post methods. You would be more consistent if the remaining views were CBV, you would worry less about future-changes that might introduce some complexity.
If your logic is too complicated and you can’t find a corresponding CBV, you’re probably lying or doing something wrong. Just be realistic, at the end of the day you do one of these: create, read, update and delete, which all have corresponding views. Let’s say your point is fair and your logic indeed doesn’t fit into anything, then how come such complexity will be handled in a function-based view, with endless indentation and conditional logic? Just use View (at worst) and OOP structures to make sure your logic stays understandable.
Class based views take up too much space
In some cases, especially when writing simple logic, CBV take more space than function-based views. But you don’t really count the amount of lines you save up, do you? Let’s say you did and CBV still had longer lines. Then what? It’s a good compromise; CBV promotes scalability and readability.
Class based views are too complicated! or All the logic is hidden, I don’t understand anything!
CBV are not complicated, they are complex. It requires a good understanding of object oriented paradigm and that’s why being able to use them makes you a better Django developer. If you understand CBV, you will understand views that make use of it; if you continue using function-based views, you will be writing complicated views that even you won’t understand some three months later.
All the logic is indeed hidden and that’s one of the things we actually want; we want to reach business logic as soon as possible and anything unrelated can remain hidden at the depths of abstraction (that’s why you use Django in the first place). Django is open source, just delve into the code and figure out what is being done.
How come they didn’t remove function-based views if CBV is superior?
Well, at the heart of every web framework lies a callable that takes a request and returns a response; that’s just how they work. You just can’t remove this key internal mechanism; CBV are just wrappers around this structure.
*Besides, it has one great use case: learning. If you are just starting Django, you better start with function-based views to grasp the mechanisms of request-response cycle and how they are handled; generic CBV will handle these for you later.
I will keep adding my responses if I hear other arguments against CBV.
