1.10. Guided Tour and How To Use This Book¶

As this chapter’s Concepts and Prerequisites described, becoming a skilled software engineer requires both conceptual understanding and plenty of hands-on practice. Therefore, our goal in each chapter is to give you the necessary conceptual foundations to work on the exercises, where the real learning happens.

The rest of the book is divided into two parts. Part I explains Software as a Service, and Part II explains modern software development, with a heavy emphasis on Agile.

Chapter 3 starts Part I with an explanation of the architecture of a SaaS application, and how the Web went from a collection of static pages to an ecosystem of services characterized by RESTful APIs—that is, Application Programming Interfaces based on the design stance of REpresentational State Transfer.

Since languages and frameworks evolve rapidly, we believe learning how to learn new languages and frameworks is a more valuable skill than knowing a specific language or framework. Thus, Chapter 2 introduces our methodology for doing so, using Ruby as an example, for programmers already familiar with another modern language such as Java or Python

Similarly, today the main reason for learning a new language is often the desire to use a framework that relies on that language. A good framework both reifies a particular application architecture and takes advantage of the features of a particular language to make development easy when it conforms to that architecture. Chapter 4 introduces the basics of Rails and its central metaphor of the Model–View–Controller architecture. Chapter 5 covers more advanced Rails features and shows in more depth how Rails takes advantage of Ruby’s language features. Splitting the material this way allows for readers who want to get started writing an app as soon as they can, which just requires Chapter 4. While the material in Chapter 5 is more challenging to learn and understand, your application can be DRYer and more concise if you use concepts like partials, validations, lifecycle callbacks, filters, associations, and foreign keys. Readers already familiar with Ruby and Rails may want to skim or skip these chapters.

Building on the familiarity with Ruby and Rails by this point in the book, Chapter 6 introduces the programming language JavaScript, its productive framework jQuery, and the testing tool Jasmine. Just as the Rails framework amplifies the power and productivity of the Ruby language for creating the server side of SaaS apps, the jQuery framework amplifies the power and productivity of JavaScript for enhancing its client side. And just as RSpec makes it possible to write powerful automated tests to increase our confidence in our Ruby and Rails code, Jasmine makes it possible to write similar tests to increase our confidence in our JavaScript code.

Given this background, the next six chapters of Part II illustrate important software engineering principles using Rails tools to build and deploy a SaaS app. Figure 1.9 shows one iteration of the Agile lifecycle, which we use as a framework on which to hang the next chapters of the book.

Chapter 7 discusses how to talk to the customer. Behavior-Driven Design (BDD) advocates writing acceptance tests that customers without a programming background can understand, called user stories, and Chapter 7 shows how to write them so that they can be turned into integration tests as well. It introduces the Cucumber tool to help automate this task. This testing tool can be used with any language and framework, not just Rails. As SaaS apps are often user facing, the chapter also covers how to prototype a useful user interface using “Lo-Fi” prototyping. It also explains the term Velocity and how to use it to measure progress in the rate that you deliver features, and introduces the SaaS-based tool Pivotal Tracker to track and calculate such measurements.

Chapter 8 covers Test-Driven Development (TDD). The chapter demonstrates how to write good, testable code and introduces the RSpec testing tool for writing unit tests, the Guard tool for automating test running, and the SimpleCov tool to measure test coverage.

Chapter 9 describes how to deal with existing code, including how to enhance legacy code. Helpfully, it shows how to use BDD and TDD to both understand and refactor code and how to use the Cucumber and RSpec tools to make this task easier.

Chapter 10 gives advice on how to organize and work as part of an effective team using the Scrum principles mentioned above. It also describes how the version control system Git and the corresponding service GitHub can let team members work on different features without interfering with each other or causing chaos in the release process.

To help you practice Don’t Repeat Yourself, Chapter 11 introduces design patterns, which are proven structural solutions to common problems in designing how classes work together, and shows how to exploit Ruby’s language features to adopt and reuse the patterns. The chapter also offers guidelines on how to write good classes. It introduces just enough UML (Unified Modeling Language) notation to help you notate design patterns and to help you make diagrams that show how the classes should work.

Note that Chapter 11 is about software architecture whereas prior chapters in Part II are about the Agile development process. We believe in a college course setting that this order will let you start an Agile iteration sooner, and we think the more iterations you do, the better you will understand the Agile lifecycle. However, as Figure 1.9 suggests, knowing design patterns will be useful when writing or refactoring code, since it is fundamental to the BDD/TDD process.

Chapter 12 offers practical advice on how to first deploy and then improve performance and scalability in the cloud, and briefly introduces some reliability and security techniques that are uniquely relevant to deploying SaaS.

We conclude with an Afterword that reflects on the material in the book and projects what might be next.

CHIPS. As Confucius said: “I hear and I forget, I see and I remember, I do and I under- stand.” The goal of the book is to give you just enough content to get a conceptual handle on the Coding/Hands-On Integrated Projects (CHIPS) interspersed with the text. Each CHIPS exercise contains significant guidance and hints for the self-learning you’ll have to do to com- plete it. If you’re using this book in conjunction with online course materials from Codio, switching between the content-oriented didactic material (COD) and the coding/hands-on integrated projects (CHIPS) is especially easy, and your assignments will be automatically graded for you.

Terminology. You will encounter many new technical terms (and buzzwords) as you dive into this rich ecosystem. To help you identify important terms, text formatted like this refers to terms with corresponding Wikipedia entries. (In the Kindle book, PDF document, and Codio book, the terms link to the appropriate Wikipedia page.) Depending on your background, we suspect you’ll need to read some chapters more than once before you get the hang of it.

Each chapter concludes with a section called Fallacies and Pitfalls, which explains common misconceptions or problems that are easy to experience if you’re not vigilant, and Concluding Remarks to provide resources for those who want to dig more deeply into some of the chapter’s concepts.

Self-Check 1.10.1. Which is most important for rapidly learning SaaS development: understanding the conceptual foundations, reading code, or writing code?

All are important. You won’t learn much by copying-and-pasting code if you don’t un- derstand why it works (or doesn’t). On the other hand, just reading about code doesn’t get anything working. Inspecting others’ high-quality code, which we hope your instructors will emphasize, not only shows you good examples but also helps cement your understanding of the conceptual foundations.