How do variables get into the controller?

Question

Laravel

For example, there is a method in the controller:

public function foo(Request $request){
 $file = $request->file();
.......
}

Where to dig to understand how the request got into the controller, because I actually don’t call it inside. I just don't even know what I need to google.

Answer 1

This is autowiring

Answer 2

Google Dependency Injection and Inversion of Control, read the Laravel documentation (you won’t believe it is there!) and Diving Laravel , study the framework code.

Answer 3

This piece - "Request $request" means that only an object of type Request can get into the variable.