Mastering Object-oriented Python

Using decorators for security

Software is filled with cross-cutting concerns, aspects that need to be implemented consistently even if they're in separate class hierarchies. It's often a mistake to try and impose a class hierarchy around a cross-cutting concern. We've looked at a few examples, such as logging and auditing.

We can't reasonably demand that every class that might need to write to the log also be a subclass of some loggable superclass. We can design a loggable mixin or a loggable decorator. These don't interfere with the proper inheritance hierarchy that we need to design to make polymorphism work correctly.

Some important cross-cutting concerns revolve around security. Within a web application, there are two sides to the security question ...