## Chapter 23: Security basics (the stuff that saves you from painful bugs) Goal of this chapter: learn the few security habits that prevent 80% of beginner mistakes. If you remember only these, you’re already ahead: 1) Treat all input as untrusted `$_GET`, `$_POST`, JSON body, headers — all can be faked. 2) Escape output based on where it goes - HTML: `htmlspecialchars(...)` - SQL: use prepared statements (PDO) 3) Validate on server, even if you validate on frontend Frontend validation is user experience. Server validation is security. 4) Don’t expose errors in production In production you log errors; you don’t print them to users. --- ### Deployment basics (what actually runs PHP on hosting) On a real server, PHP usually runs in one of these common setups: - Apache + PHP (mod_php): Apache directly runs PHP files. - Nginx + PHP-FPM: Nginx handles HTTP, PHP-FPM runs PHP, they talk to each other. Your app usually has a “public web root” folder (often named `public/`). Only that folder is exposed to the internet. Everything else (config, classes, database files) stays outside public. If you remember one simple rule for hosting: keep private files out of the public folder. --- ## Conclusion In this article, we explored the core concepts of All about PHP - Security basics (the stuff that saves you from painful bugs). Understanding these fundamentals is crucial for any developer looking to master this topic. ## Frequently Asked Questions (FAQs) **Q: What is All about PHP - Security basics (the stuff that saves you from painful bugs)?** A: All about PHP - Security basics (the stuff that saves you from painful bugs) is a fundamental concept in this programming language/topic that allows developers to perform specific tasks efficiently. **Q: Why is All about PHP - Security basics (the stuff that saves you from painful bugs) important?** A: It helps in organizing code, improving performance, and implementing complex logic in a structured way. **Q: How to get started with All about PHP - Security basics (the stuff that saves you from painful bugs)?** A: You can start by practicing the basic syntax and examples provided in this tutorial. **Q: Are there any prerequisites for All about PHP - Security basics (the stuff that saves you from painful bugs)?** A: Basic knowledge of programming logic and syntax is recommended. **Q: Can All about PHP - Security basics (the stuff that saves you from painful bugs) be used in real-world projects?** A: Yes, it is widely used in enterprise-level applications and software development. **Q: Where can I find more examples of All about PHP - Security basics (the stuff that saves you from painful bugs)?** A: You can check our blog section for more advanced tutorials and use cases. **Q: Is All about PHP - Security basics (the stuff that saves you from painful bugs) suitable for beginners?** A: Yes, our guide is designed to be beginner-friendly with clear explanations. **Q: How does All about PHP - Security basics (the stuff that saves you from painful bugs) improve code quality?** A: By providing a standardized way to handle logic, it makes code more readable and maintainable. **Q: What are common mistakes when using All about PHP - Security basics (the stuff that saves you from painful bugs)?** A: Common mistakes include incorrect syntax usage and not following best practices, which we've covered here. **Q: Does this tutorial cover advanced All about PHP - Security basics (the stuff that saves you from painful bugs)?** A: This article covers the essentials; stay tuned for our advanced series on this topic.