I've been programming for a while, but I feel like my understanding of web application development and software design has gotten rusty. I'd like to rebuild a solid foundation, especially around principles such as Single Responsibility, object-oriented programming, and common design patterns. I also want to review the security issues web applications need to defend against, including SQL injection and cross-site scripting. I primarily work with PHP, so PHP-focused resources or practical project ideas would be especially useful.
2 Answers
A good book may be the best fit if you want a structured review. “Mastering PHP Design Patterns” by Junade Ali is somewhat dated and focuses on PHP 7, but it covers many of the common patterns and can still be useful for revisiting object-oriented design in PHP.
A practical way to refresh these skills is to rebuild one of your older projects while deliberately applying cleaner architecture and design principles. Working through real decisions—how to separate responsibilities, structure classes, and organize application layers—usually teaches more than passively following another tutorial. For security, the OWASP documentation and cheat sheets are excellent references for topics such as SQL injection, XSS, authentication, and input handling.

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