Ruby on Rails Enterprise Application Development Plan, Program, Extend Building a complete Ruby on Rails business application from start to finish Elliot Smith Rob Nichols BIRMINGHAM - MUMBAI Ruby on Rails Enterprise Application Development Plan, Program, Extend Copyright © 2007 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, Packt Publishing, nor its dealers or 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 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: November 2007 Production Reference: 1011107 Published by Packt Publishing Ltd. 32 Lincoln Road Olton Birmingham, B27 6PA, UK. ISBN 978-1-847190-85-7 www.packtpub.com Cover Image by Rob Nichols Credits Authors Project Manager Elliot Smith Abhijeet Deobhakta Rob Nichols Project Coordinator Reviewer Sagara Naik Keynan Indexer Senior Acquisition Editor Monica Ajmera David Barnes Proofreader Development Editor Cathy Cumberlidge Mithil Kulkarni Chris Smith Technical Editor Production Coordinator Swapna V. Verlekar Shantanu Zagade Editorial Manager Cover Designer Dipali Chittar Shantanu Zagade About the Authors Elliot Smith has worked in IT since 1996: at OpenAdvantage (an open-source solutions center) as a business analyst, as a learning technologist and web developer at the University of Birmingham, England, and as a technical writer for Armada Computer Publications. He runs his own training and consulting company, mooch labs, when he gets a chance. He has an M.Sc. in Artificial Intelligence and a Ph.D. in Computer Science from the University of Birmingham. He thanks Nicola, his wife, for giving him the time and space to write a book; Madeleine, his daughter, for keeping him sane while doing it; and Rob Nichols for giving him the opportunity in the first place. Rob Nichols first started using computers during his apprenticeship at Rolls-Royce in the early 1980s. At 23, he decided to change direction and started a degree in Geology and Geography at Cardiff University. By 1995 he had gained a Ph.D. from Bristol University, studying the behavior of quicksand. During his time in Bristol and in a subsequent lectureship at Leeds University, he started using the fledgling Internet to communicate with co-workers, gather information, and present Geological information in the form of his first web pages. Following his return to Britain from a lectureship in U.S.P. Fiji, Rob found himself without another lectureship position to go on to. So, changing direction again, he started working for a U.K. computer manufacturer, where he rose to the position of Engineering Manager, managing a team of seventy maintenance and networking engineers, and support staff. Following the collapse of the U.K. computer market in 2002 he moved on to the role of IT manager for a small business providing products and services to the water industry. In this role, Rob has had great success developing intranet-based business applications that streamlined business processes, saved time, and increased efficiency. In doing so, he transformed the IT department from a business cost to a profit generator by reducing costs and thereby increasing margins. When not working with computers, Rob and his wife reside happily in a small Midlands town in England, where he writes scripts for the local movie-makers club and photographs the local wildlife. Thank-you Diane, for putting up with my disappearances into the study to "work on the book". Table of Contents Preface 1 Chapter 1: Introduction 7 Why this Book? 7 Why Develop? 8 Why a Client/Server Based Web Application? 9 But why Ruby on Rails? 11 Rails Handles Menial Tasks 11 Clear Code 12 Text Based File 13 Open Source 14 Plentiful Documentation 14 Built-in Safe Test Environment 15 Ruby on Rails in Detail 15 Summary 16 Chapter 2: The Initial Problem 17 A Normal Day in the Office 17 Examining the Data 19 Data Objects 20 Database Table Design Rules 21 Separating the Data 22 Naming Conventions 22 Use Meaningful Names 22 Use a Consistent Naming Convention 23 Ruby on Rails Naming Conventions 24 Constants and Classes 24 Variables 24 Methods and Properties 24 Special Method and Property Suffixes 25 Reserved Words 26 Table of Contents Back to the Data 26 Review the Result 29 Project Preparation Steps 30 How Good is the Source Data? 30 Tracking Who does What 32 No Log-On and No Authentication 33 Simple Password Access 34 User Log-On 35 Recording Access History 35 Access Control for Rory's Application 36 Data Validation 37 The Minimum Required Data is Entered 37 Each Record can be Uniquely Identified 38 Identify Fields that Need to Have a Particular Format 39 References to Data in Other Tables Point to Actual Data 41 Rory's Data 41 Person 42 Company 42 Address 42 Summary 42 Chapter 3: Laying the Foundations 43 Supporting Rails Development 43 Addressing the Challenges 45 Setting Up a Rails Stack 46 Installing a Rails Stack Using a Bundle 48 Installing a Custom Rails Stack 49 Installing Ruby and Rubygems 49 Ruby on Windows 50 Ruby on Linux 51 Ruby on Mac OS X 52 Installing Rails 52 A Note on Rails Documentation 53 Other Libraries 55 Capistrano for Easier Deployment 55 Mongrel: A Better Way to Run Rails Applications 56 Choosing a Database Platform 57 Installing MySQL 58 Checking Your MySQL Installation 61 MySQL GUI Tools 62 Ruby-MySQL: Making Ruby and MySQL Work Better Together 62 Installing an IDE 64 Eclipse 65 EasyEclipse 67 [ ii ] Table of Contents Instructions for Masochists 71 In the Back Rooms at Acme… 71 Setting Up a Team Server 72 Quick Gem Installation 73 Remote Access via SSH 74 Adding Users 74 Version Control with Subversion 75 Subversion Standard Practices 77 Setting Up a Subversion Repository 81 Setting Up a Project in Subversion 82 Browsing Subversion from Eclipse 83 Other Subversion Clients 88 Using Other People's Servers 88 Back at Acme 88 Summary 89 Chapter 4: Working with Rails 91 The World According to Rails 92 Model-View-Controller Architecture 92 Convention over Configuration 94 Rails and MVC 95 Setting Up a New Rails Application 97 Using Mongrel to Serve Your Application 100 Connecting Rails to a Database 103 Creating a Database and System Account 104 Setting Up a Database Connection 106 Configuring the Rails Environments 108 Testing the Database Connection 111 Troubleshooting a MySQL Connection 112 ActiveRecord, Migrations, and Models 113 Model == Table 114 Which Comes First: The Model or The Table? 114 Building a Model with Migrations 115 Converting a Data Structure into a Migration 117 Defining Columns in Migrations 119 Other Operations Available in a Migration 121 Running a Migration 122 Rolling Back to a Previous Version of the Database 124 The Scaffold 125 Completing the Database 127 The companies Table 127 The addresses Table 127 Generating the Remaining Tables 128 Models in Detail 129 [ iii ]