This book is about copying. Copying has an unpleasant reputation in these copyright and intellectual property sensitive times, but it's probably unknown to many, that it has an illustrious past. When we were babies, the main way we learnt was through copying what our parents did. If you have young children you soon learn to your regret the first time you utter any insalubrious words and how quickly your child copies your exclamation and mannerisms. Our number system was copied from the Arabs (that's why they are called Arabic numerals) but it was first used by the Indians from the Indian subcontinent, and subsequently copied by the Arabs in the Middle-East. The English language regularly copies words from other languages. In fact the word 'copy' comes from the Old French word copie which comes from the Medieval Latin word copia.
That is not to say infringing copyright is the right thing to do when someone else has spent tremendous effort in coming up with the original. However, it should be recognized that not all things are copyrightable, patentable, or can be trademarked, and that is for a good reason. Ideas for example are generally not considered as intellectual property. Copyright is the protection of expressions of ideas, not the protection of the ideas themselves. Patent law is used for the protection of inventions for a limited time in return for the disclosure of the invention. Again it is not a protection of ideas; the concept of patent law is to promote the liberation of the idea in exchange for limited monopoly. Google is well known to have dominance in the search engine market but it doesn't mean it has monopoly on search engines. Anyone else is free to write his/her own search engine (though taking part of Google's search engine code to write your own search engine is copyright infringement).
This idea of copying is the basis of the book you are holding. In short, the premise of this book is to learn how each of the popular Internet applications we clone work through copying the ideas behind them.
In this chapter we will cover:
- A brief description of the type of people who would like to read this book
- The popular Internet applications described in this book and why we chose them
- The various technologies used in this book, including Sinatra, DataMapper, and Haml
The primary audience for this book are Ruby programmers with an intermediate level of experience in Ruby as well as web application programming. This sounds quite limiting but in reality if you have any intermediate level of programming in any object-oriented language you should be able to follow the implementations with relative ease. Of course, if you know something about the Ruby programming language it helps a lot too.
The technology stack that we will be using for these clones is slightly off the usual track for the Ruby on Rails crowd. The main reason is because it's a simpler stack to use. Ruby on Rails, while extremely easy to use and very powerful, has a lot of added frills to the framework, which adds on unnecessary complexity for a book that focuses on clones and features of the clones only. The chosen stack however does not different too greatly for programmers who are familiar with Rails. In this chapter we will go through all that is needed to follow the rest of the chapters in this book.
So why are we interested in cloning these applications at all, since we can't possibly build a clone that is better than the original? There are plenty of reasons for doing so but let me just give four common ones:
- To learn how these applications work. We use them all the time and while we would know how these applications functionally work, cloning them will teach us how these features can be implemented. Although the implementation is not definitive, at least learning how difficult or easy it is to clone them gives us a better appreciation of how things work behind the scenes to provide us with the features.
- To incorporate features of the clones into your own application. As you will see in this book, each chapter shows how key features in those applications are implemented. If you want to build these key features into your own application, learning how these features are implemented will give you an insight into building them for your own use.
- To build a customized clone. While each popular Internet application has plenty of features to go with, there will be special niche needs that can only be fulfilled by a customized version of that application.
- Learning the technology stack. The best way to learn any new technology stack is to build something with it. Going through the chapters in this book will give you ample exercise in this stack.
If you find yourself having any of the above needs then this book is for you.