Protected globals

• Explain hidden coupling and unpredictable state.
• Explain the security and maintainability issues of raw superglobals.

Protected global variables in WebEngine

• Cover $_GET, $_POST, $_FILES, $_COOKIE, $_SERVER, and related global state.
• Explain the framework’s object-oriented replacements.

Encapsulation

• Encourage explicit dependencies through services and parameters.
• Explain why this improves testability.
• Explain the term "encapsulation" and the benefits it brings to code.

When global state is still necessary

• Environment variables.
• PHP runtime behaviour.
• Third-party libraries that assume globals. Exaplin how to whitelist or reconstruct.

---

In the next section we will learn how to build API responses.