Mastering Python Design Patterns - Second Edition

Real-world examples

Chip (also known as Chip and PIN) cards (j.mp/wichpin) offer a good example of how a protective proxy is used in real life. The debit/credit card contains a chip that first needs to be read by the ATM or card reader. After the chip is verified, a password (PIN) is required to complete the transaction. This means that you cannot make any transactions without physically presenting the card and knowing the PIN.

A bank check that is used instead of cash to make purchases and deals is an example of a remote proxy. The check gives access to a bank account.

In software, the weakref module of Python contains a proxy() method that accepts an input object and returns a smart proxy to it. Weak references are the recommended way to ...