Primer on Ruby on Rails

This article introduces a web development framework named Ruby on Rails popularly known as “RoR”. It explains the basic concepts of web development and how RoR fits the web development to the ‘T’. You don’t need technical background to understand this article. Though technical terms are used, they are explained in an easy to understand language. If you are an experienced web developer from other frameworks, this will create a perspective on Ruby-On-Rails framework.

Ruby

Ruby is a programming language. It was created 20 years ago by Yukihiro “Matz” Matsumoto. The official website of Ruby programming language is
here. By most measures of programming language popularity, Ruby ranks among the top ten, largely due to the popularity of Rails. Like Java or the C language, Ruby is a general-purpose programming language, though it is best known for its use in web programming.

Rails

Rails is a software library that extends the Ruby programming language created by David Heinemeier Hansson (popularly known as DHH) is its creator.

It is a software program written in Ruby programming language. Technically, it is a package library (specifically, a RubyGem), that is installed using the operating system command-line interface.

Rails is a framework for building websites. As such, Rails establishes conventions for easier collaboration and maintenance. These conventions are codified as the Rails API (the application programming interface, or directives that control the code). The Rails API is documented online and described in books, articles, and blog posts. Learning Rails means learning how to use the Rails conventions and its API.

Rails combines the Ruby programming language with HTML, CSS, and JavaScript to create a web application that runs on a web server. Because it runs on a web server, Rails is considered a server-side, or “back end,” web application development platform (the web browser is the “front end”).

Rails, in a larger sense, is more than a software library and an API. Rails is the central project of a vast community that produces software libraries that simplify the task of building complex websites. Members of the Rails community share many core values, often use the same tools, and support each other with an informal network that is built on volunteerism. Overlapping the informal community is an economic network that includes jobs, recruiters, consulting firms, conferences, businesses that build websites with Rails, and investors that fund startups. Rails is popular among web startups, significantly because the pool of open source software libraries (RubyGems, or “gems”) makes it possible to build complex sites quickly.

Why Ruby?

In a podcast from This Developer’s Life and in an interview from 2005, David Heinemeier Hansson, the creator of Rails, describes building an online project management application named BaseCamp in 2004. He had been using the PHP programming language because he could get things done quickly but was frustrated because of a lack of abstraction and frequently repetitive code that made PHP “dirty.” Hansson wanted to use the “clean” software engineering abstractions supported in the Java programming language but found development in Java was cumbersome. He tried Ruby and was excited about the ease of use (he calls it pleasure) he found in the Ruby language.

Ruby is known among programmers for a terse, uncluttered syntax that doesn’t require a lot of extra punctuation. Compared to Java, Ruby is streamlined, with less code required to create basic structures such as data fields. Ruby is a modern language that makes it easy to use high-level abstractions such as meta-programming. In particular, meta-programming makes it easy to develop a “domain specific language” that customizes Ruby for a particular set of uses (Rails and many gems use this “DSL” capability).

Ruby’s key advantage is RubyGems, the package manager that makes it easy to create and share software libraries (gems) that extend Ruby. RubyGems provides a simple system to install gems. Anyone can upload a gem to the central RubyGems website, making the gem immediately available for installation by anyone. The RubyGems website is where you’ll obtain the most recent version of Rails. And it is where you will obtain all the gems that help you build complex websites.

Why Rail?

Rail is popular and widely used because its conventions are pervasive and astute. Any web application has complex requirements that include basic functions such as generating HTML, processing form submissions, or accessing a database. Without a web application development framework, a programmer has a mammoth task to implement all the required infrastructure. Even with a web application development framework, a programmer can take an idiosyncratic approach, building something that no one else can easily take apart and understand. The singular virtue of Rails is that DHH, and the core team that joined him, decided that there is one best way to implement much of the infrastructure required by a web application. Many of the implementation decisions appear arbitrary. In fact, though DHH is often lambasted as autocratic in his approach to improving Rails, the Rails API reflects deep experience and intelligence in implementing the requirements of a web application development framework. The benefit is that every developer who learns the “Rails way” produces a web application that any other Rails developer can unravel and understand more quickly than if they encountered idiosyncratic code without as many conventions. That means collaboration is easier, development is quicker, and there’s a larger pool of open source libraries to enhance Rails.

The advantage of establishing conventions might seem obvious, but when Rails was released in 2004, web development was dominated by PHP, which lent itself to idiosyncratic code produced by solo webmasters, and Java frameworks such as Struts, which were often seen as burdened by an excess of structure. Other frameworks, such as Apple’s WebObjects, Adobe’s ColdFusion, and Microsoft’s .NET Framework, were in wide use but the frameworks were products controlled by the companies and built by small teams, which tended to restrict innovation. Today PHP, Java frameworks, and .NET remain popular, largely among solo webmasters (PHP), enterprise teams (Java), and Windows aficionados (.NET) but Rails has become very popular and has influenced development of other server-side frameworks.

The design decisions that went into the first version of Rails anchored a virtuous circle that led to Rails’s growth. Within the first year, Rails caught the attention of prominent software engineers, notably Martin Fowler and Dave Thomas (proponents of agile software development methodologies). Rails is well-matched to the practices of agile software development, particular in its emphasis on software testing and “convention over configuration.” The interest and advocacy of opinion leaders from the agile camp led to greater visibility in the wider open source community, culminating in a keynote lecture by Heinemeier Hansson at the 2005 O’Reilly Open Source Convention. Because Rails was adopted by software engineers who are influencers and trend setters, it is often said that Rails is favored by “the cool kids.” If that is so, it is largely because Rails is well-suited to software engineering practices that are promoted by thought leaders like Fowler and Thomas.

How Rail Works

With an understanding in place of the Rails guiding principles and its challenges, let’s start from scratch to get a clear picture of how Rails works. We’ll start by explaining how a web application is used to create a website. You may already know most of this, but let’s review because it will help explain how Rails works.

You’re running a web browser on your computer (probably to read this article). A web browser combines three kinds of files—HTML, CSS, and JavaScript—to display web pages. A browser obtains the files from a web server. The web server can be remote (connected by the Internet) or on your own computer (when you are doing development).

You might have learned how to create HTML, CSS, and JavaScript files. HTML (HyperText Markup Language) is a convention for creating structured documents that combine content (such as text, images, or video) with generic typographic, layout and design elements (such as headlines and tables). CSS (Cascading Style Sheets) directives apply a specific appearance to typographic, layout and design elements.JavaScript is a programming language supported by all web browsers that is used to manipulate HTML and CSS elements, particularly for implementing interactive features such as tabs and modal windows. You can learn about HTML, CSS, and JavaScript in a typical “Introduction to Web Design” course that teaches how to make “static websites.”

Web servers deliver HTML, CSS, and JavaScript, either from static files that are stored on the server, or from an “application server” that creates files dynamically using a programming language such as Ruby. A software program written in Ruby and organized using Rails conventions is a “web application.” Rails combines the Ruby programming language with HTML, CSS, and JavaScript to create a web application. Rails uses Ruby to dynamically assemble HTML, CSS, and JavaScript files from component files (often adding content from a database).

Why create a web application? A web browser needs only a single HTML file to display a web page (CSS and JavaScript files are optional). However, if you are creating several web pages, you might want to assemble the HTML file from smaller components. For example, you might make a small file that will be included on every page to make a footer (Rails calls these “partials”). Consider another example: If you are displaying content from a database, you might not want the complex programming code that accesses the database mixed into your HTML(programmers call this
separation of concerns and it makes for more modular, maintainable programs). Finally, if you are using a web application server such as the one supplied with Rails, you can add features to your website that have been developed and tested by other people so you don’t have to build everything yourself. These are all reasons to create a web application using Ruby on Rails.

We will delve deeper into the Rails world over a series of articles.