thin controllers - fat models (proper code structure for mvc)

Thin controllers - fat models

How to write better code- MVC -

Damian Sromek

damiansromek.pl

2012-03

WARNING: Do not try it at home/work!

The WRONG way - "mvC"

mvC - Controller

● Whole business logic in a Controller. Controller: I'll do everything for you.You can keep everything in one place.That's so simple!

mvC - Model

● Models used basically just to store data in database.

Model: I'm just a data so why should I do anything more than just exist?

mvC - View

● View uses the database directly or via MysqliResult etc.

View:Just give me database connection and I'll do everything!Give me more power and you won't need controllers and models at all!

mvC - problems?

● Copy/Paste to "reuse" the code.● Long and complex methods (actions) that

need to be copied in order to use polymorphism.

● Very difficult to test.

You will pay for mvC

Makes your life easier

The RIGHT way - MVC

MVC - Controller

● Just a translator for a user wishes (request) so model and view can understand and respond in proper way (response).

Controller:I should be so thin you should barely notice me.I'll just tell model what user did and the view to show what he wants - facade for business logic.

MVC - Model

● This is where whole "magic" should happen.● Model should store and manipulate data.● It should be used intensively by controllers to

do what user requested and by views to show data user wants to see.

● Business logic should be in models, eg. "$ageLimit > 20".

Model:I'm the proper guy for doing the hard work.I know how your app should work and why.

MVC - View

● Gets a model or a collection of models selected by controller (according to user request) and shows it.

● It tells the controller what user has done and what does he expect to happen.

View:I'll show you what you want and let you do cool things with models.

MVC - Action helper

● Easy and good way to reuse code between controllers.

● Thanks to models it's using it keeps things DRY.

● Prefer action helper over methods put in controllers extended by other controllers.

Action helper:I can do common things with the models according to the request. I'm the controllers ... helper.

MVC - View helper

● Helps you render HTML template that you use on many views.

View helper:I can help you make things (php, js and html code) look nice.

OOP - Model

● If you think you're using OOP because you have classes - you are wrong!

● "Happy" object should have just one responsibility. "Fat model" does not mean it has to have hundred lines of code.

● Object should be easy to test. You should be able to "mock" things it's using.

● Let object be dependent - inject into it the things it needs.

MVC - JavaScript

● All those rules applies to JavaScript and other languages.

● JavaScript code is also great when you use MVC!

So you should/could have:MV(JS: MVC)C

Zend Framework uses MVC - really?

● It's not a "true" MVC.● MVC was designed for desktop apps.● It has many "branches". @see MVP@see Model2 ("MVC for web apps")

Questions?

I will help you google the answer if you ask difficult question ;D Thank You.Damian

Bibliography

Images found on the Internet and are not my property. - http://survivethedeepend.com/ (Zend Framework Book: Surviving The Deep End)