Book Image

Polished Ruby Programming

By : Jeremy Evans
5 (1)
Book Image

Polished Ruby Programming

5 (1)
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)
1
Section 1: Fundamental Ruby Programming Principles
8
Section 2: Ruby Library Programming Principles
17
Section 3: Ruby Web Programming Principles

Designing exception class hierarchies

In general, if you are writing a library and raising an exception in it, it is useful to have a custom exception subclass that you use. Let's say you are passing an object to your method, and the object has to be allowed, or an exception should be raised. Ruby allows you to do this by using the following code:

def foo(bar)
  unless allowed?(bar)
    raise "bad bar: #{bar.inspect}"
  end
end

However, this is a bad approach, as it raises RuntimeError. In general, it is better to raise an exception class related to your library, since that allows users of your library to handle the exception differently from exceptions in other libraries. So if you have a library named Foo, it's common to have an exception class named something like Foo::Error that you can use for exceptions raised by the library. The following code demonstrates this:

module Foo
  class Error < StandardError...