Book Image

Polished Ruby Programming

By : Jeremy Evans
Book Image

Polished Ruby Programming

By: Jeremy Evans

Overview of this book

Anyone striving to become an expert Ruby programmer needs to be able to write maintainable applications. Polished Ruby Programming will help you get better at designing scalable and robust Ruby programs, so that no matter how big the codebase grows, maintaining it will be a breeze. This book takes you on a journey through implementation approaches for many common programming situations, the trade-offs inherent in each approach, and why you may choose to use different approaches in different situations. You'll start by refreshing Ruby fundamentals, such as correctly using core classes, class and method design, variable usage, error handling, and code formatting. Then you'll move on to higher-level programming principles, such as library design, use of metaprogramming and domain-specific languages, and refactoring. Finally, you'll learn principles specific to web application development, such as how to choose a database and web framework, and how to use advanced security features. By the end of this Ruby programming book, you’ll be a well rounded web developer with a deep understanding of Ruby. While most code examples and principles discussed in the book apply to all Ruby versions, some examples and principles are specific to Ruby 3.0, the latest release at the time of publication.
Table of Contents (23 chapters)
Section 1: Fundamental Ruby Programming Principles
Section 2: Ruby Library Programming Principles
Section 3: Ruby Web Programming Principles

Avoiding injection

Injection vulnerabilities occur when an attacker can inject code into your application. There are three common types of injection vulnerabilities in Ruby web applications: script injection, SQL injection, and code injection (remote code execution). We'll look at these in more detail in the following subsections.

Script injection

Script injection, otherwise known as cross-site scripting or XSS for short, is a vulnerability where an attacker can cause their code to be used in your web pages. It's not nearly as bad as SQL injection and code injection, but it can still cause significant problems. For example, let's say you are using Sinatra or Roda for your application, and you have the following code in one of your views:

# In your ERB code:
# <p>Added by: <%= params['name'] %></p>

Here, an attacker can redirect someone they know who uses your site with a path such as /path/to/action?name=%3Cscript%3EDo+bad+things...