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- Herausgeber: Packt Publishing
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Design and deploy your own web application in minutes using Sinatra
About This Book
- Exploit Sinatra to design a web application
- Integrate external, internal, and inline CSS and use some popular CSS frameworks
- Deploy an application onto your own server or on a cloud application platform
Who This Book Is For
Learning Sinatra is a great place to start your first Sinatra application. It doesn't matter whether you have written a web application before or not, though some basic knowledge of programming is essential.
What You Will Learn
- Install and set up Ruby and Sinatra
- Work with layouts and template routes
- Extend the code to include CSS in different ways
- Create projects and understand MVC
- Design the front-end with Twitter Bootstrap
- Use the MySQL/SQLite gem to communicate with databases
- Implement sessions that can be used across multiple pages
- Utilize the innovative and user-friendly features of ORMs
In Detail
Sinatra is a Ruby framework that is widely used in the Industry. You can use it to make a single-page web app or a large-scale one. With the increased online footprint, you can create and deploy your own application.
Whether you are brand-new to online learning or a seasoned expert, this book will provide you with the skills you need to successfully create, customize, and deploy a Sinatra application. Starting from the beginning, this book will cover how to install Ruby and Sinatra, construct the back-end, design and customize the front-end layout, and utilize the innovative and user-friendly features of ORMs. By sequentially working through the steps in each chapter, you will quickly master Sinatra's features to create your own application.
With ample screenshots and code that offers a play-by-play account of how to build an application, Learning Sinatra will ensure your success with this cutting-edge framework.
Style and approach
This book takes a step-by-step approach to Sinatra and explains it in a conversational and easy-to-follow style. A simple project is used as a base to explain each topic. The code and screenshots included add to the ease of learning.
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Seitenzahl: 182
Veröffentlichungsjahr: 2016
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Table of Contents
Learning Sinatra
Learning Sinatra
Copyright © 2016 Packt Publishing
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.
Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the authors, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.
Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.
First published: April 2016
Production reference: 1220416
Published by Packt Publishing Ltd.
Livery Place
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Birmingham B3 2PB, UK.
ISBN 978-1-84951-930-4
www.packtpub.com
Credits
Authors
Sudeep Agarwal
Manoj Sehrawat
Reviewer
Ken Taylor
Commissioning Editor
Jonathan Titmus
Acquisition Editor
Nadeem Bagban
Content Development Editor
Onkar Wani
Technical Editor
Danish Shaikh
Copy Editor
Tasneem Fatehi
Project Coordinator
Bijal Patel
Proofreader
Safis Editing
Indexer
Mariammal Chettiyar
Production Coordinator
Arvindkumar Gupta
Cover Work
Arvindkumar Gupta
About the Authors
Sudeep Agarwal is a site reliability engineer at Inmobi with a total of four years of experience in the industry. He was with Directi for 3 years right after finishing his education from NIT Trichy. At Directi, he was a part of the team that wrote one of the most widely used in-house web-based applications; this is where his interest in Sinatra started and he used it to write some of his personal projects. Although he is not writing a lot of web applications at Inmobi, he is still contributing to one of the ORMs—Ruby Object Mapper.
This book would not have been possible without the constant support of my family, friends, and peers. I thank everyone for keeping me motivated and helping me with their suggestions. This book is dedicated to each one of them.
Manoj Sehrawat is an enthusiastic software developer who loves coding and learning new things. He has around 5 years of experience in software development. Manoj holds an MCA from KIIT, Gurgaon and a BCA from IGNOU. Currently, he is the associate technical lead at TravelTriangle. TravelTriangle is India's first full stack holiday marketplace that connects travelers with verified travel agents. Before joining TravelTriangle, Manoj was working with StudyPad and Fizzy Software Pvt Ltd as a senior software developer. His primary focus is the design and construction of scalable and optimized web applications and APIs using a Ruby-based development stack with frameworks such as Ruby on Rails, Sinatra, and others. He is passionate about refactoring, optimizing code, and building scalable solutions with simplicity.
I would like to thank several people who helped and supported me in making this book a reality. First, I want to thank my family and fiancé for having the patience with me for taking yet another challenge, which decreases the amount of time I can spend with them.
I must mention that the PECT team is responsible for having me on the team and giving me the opportunity to write this book. I want to thank three of our editors and technical reviewers who worked on this book.
Finally, thanks to the Sinatra and Ruby community!
About the Reviewer
Ken Taylor has worked in software development and technology for over 15 years. During the course of his career, he has worked as a systems analyst on multiple software projects in several industries as well as U.S. government agencies. He has successfully used Ruby (and DSLs like Sinatra) on multiple projects. Ken previously reviewed the books RabbitMQ Cookbook and RabbitMQ Essentials by Packt Publishing. He is an organizer for Google Developer Groups (GDG) and a member and speaker for both 757 Ruby users and the Hampton Roads .NET (HRNUG) users groups. Ken holds an A.S. in computer science from Paul D. Camp Community College and was awarded a U.S. patent for a real estate financial software product. He is currently working as an independent consultant for Onixle LLC. He lives in Virginia Beach, Virginia with his lovely wife, Lucia, and his two sons, Kaide and Wyatt.
I would like to thank my family for being a constant support in all of my endeavors.
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Preface
This book will help you understand the basic concepts of Sinatra and build lightweight web applications. The book follows a step-by-step course, right from setting up Ruby and installing Sinatra to inculcating best practices for writing beautiful code. By the end, you will have a running Sinatra app ready and the confidence to write more apps by yourself.
What this book covers
Chapter 1, Introduction to Sinatra, helps you set up Sinatra and see a sample Hello World app, followed by a quick comparison with Rails.
Chapter 2, Introduction to Ruby, is intended for Ruby newbies, which helps in setting up Ruby using rvm and understanding how to write code in Ruby.
Chapter 3, Hello World, helps you write the skeleton of a ToDo app and understand it line by line.
Chapter 4, Modeling the Backend, introduces the concept of ORMs to the user, which is required in order to write the ToDo app.
Chapter 5, HandlingHTTP Requests, introduces the concept of controllers and explains how the request-response transaction is implemented.
Chapter 6, Designing the Frontend Layout, introduces HAML and Twitter Bootstrap, which is used to make beautiful user interfaces easily.
Chapter 7, Handling User Data, shows you how to create a form and its necessary attributes, and explains how it works. We will see the importance and usage of the method and action attributes of a form. We will create a for loop to add a List and Items of a list to a single form, where we will see how we can add an array of values to the HTML input. You will also learn how to add items to the form through JavaScript dynamically using a simple dummy template. We will see how to handle data at the backend sent by a user through filling in a form, and discuss validations and the types of validation.
Chapter 8, Connecting to a Database, covers how to connect to a database (MySQL) with various necessary parameters. You will learn how to use the mysql gem with sequel. We will also cover how to open and use an interactive console with Sinatra and Sequel and the details of Sequel models with various useful class-level and instance-level methods. We will discuss hooks and callbacks available and associations with eager loading and joins in order to scale and optimize the application.
Chapter 9, Authentication and Authorization, shows you the basics of a session in general and how we can configure it with Sinatra, both with simple and advanced options. We will see the various useful methods of a session object and the meaning of authentication and authorization individually.
Chapter 10, Deploying the App, discusses what deployment is, Heroku, and how we can use Heroku to deploy our app. You will also learn the initial setup steps that we need to do on Heroku, and about various Heroku commands and their billing models.
What you need for this book
A basic knowledge of tools and technologies used to write web applications such as HTML, databases, and others. Previous knowledge of any other dynamic language such as Python might help you, but the book covers an introduction to Ruby for first-timers.
Who this book is for
This book will be useful to someone who wants to write lightweight web applications of any size on their own. Someone who wants to move to Ruby-based frameworks from other languages would also find this book interesting.
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Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "We can include other contexts through the use of the include directive."
A block of code is set as follows:
When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:
Any command-line input or output is written as follows:
New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Clicking the Next button moves you to the next screen."
Note
Warnings or important notes appear in a box like this.
Tip
Tips and tricks appear like this.
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Chapter 1. Introduction to Sinatra
Sinatra is a Ruby-based application framework used to create web applications quickly. It can be used to write simple single-page applications or large and complex ones. Sinatra is very lightweight as it does not include a variety of gems, though the user can include gems as required.
Sinatra is widely used across the globe and has gained a lot of popularity because of its flexibility. It does not follow the Model-View-Controller (MVC) architectural pattern completely but it is fairly simple to build one on top of Sinatra. Sinatra is a View-Controller framework.
If you have been working with Ruby, you can go ahead and try out the codes; otherwise, you can go ahead with this chapter as we will be covering some basic Ruby in the next chapter. In this chapter, we will be discussing the following topics:
What is MVC?
The MVC (Model-View-Controller) is an architectural pattern that divides the application in three parts, namely, the model (the data), view (the user interfaces), and controller (the interconnections between the model and view).
MVC separates the code based on their responsibilities and makes it easier to understand and maintain:
Figure 1-1: MVC components
The concept of MVC will be clearer once we get into the examples using Sinatra.
Installing Sinatra
Sinatra is just another gem and there is no special way to install it. We use the gem install command:
This will install the latest version of the Sinatra gem and all its dependencies on your system. To see which version is installed, use the following:
Writing your first Sinatra application
Let's see how to write a bare minimum Sinatra application. We will open a new file and write the following code:
Save the file with a .rb extension (say, helloworld.rb) and execute this on the command line:
This will interpret the code and start the built-in server.
Now, we open the browser and point it to http://localhost:4567.
What did the code do?
This tells the Ruby interpreter to load the Sinatra gem:
This forms a ruby code-block. Let's understand each line.
This block is invoked when the server receives a get request on the '/' path.
This will return the 'Hello World!' string to the client.
This ends the code-block.
Where is the MVC in this code?
Sinatra does not follow the MVC architecture completely; it is a VC framework. It was mentioned earlier that the model is the data part of the application, view is the user interface, and controller is the interconnection. Now, let's find these parts in the preceding code:
Here, line 1 requires just the gem. Lines 3 to 5 define a code-block that is invoked on receiving a get request and returns a value. So here, this code-block forms the controller. It controls what to return when a request is received.
The view is the page rendered by the browser. We do not have a separate view here but line 4 defines the contents of the view.
How to achieve MVC using Sinatra
To achieve MVC using Sinatra, we need to pick a database framework and use it with Sinatra. There are many database frameworks available, such as Active Record, DataMapper, Sequel, and others. In the later chapters, we will be working with Sequel.
Sinatra application layout
As Sinatra can be used for applications that can be bare minimum or large and complex, the application structure can grow bigger with the need.
For now, let's stick to the basic layout.
A basic Sinatra application will have a ruby file that has all the controllers defined (for example, helloworld.rb).
