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B13.0 printing, February 2, 2011 Version: 2011-2-2 Prepared exclusively for Anton Fonarev Contents Changes in the Beta Releases 10 Beta 13—February 2 ........................... 10 Beta 12—January 10 .......................... 10 Beta 11—November 24 ......................... 10 Beta 10—October 28 ........................... 10 Beta 9—October 6 ............................ 11 Beta 8—September 9 .......................... 11 Beta 7—August 25 ............................ 12 Beta 6—July 27 .............................. 12 Beta 5—June 28 ............................. 12 Beta 4—May 26 .............................. 13 Beta 3—May 11 .............................. 13 Beta 2—May 3 .............................. 13 Preface to the Fourth Edition 15 Acknowledgments 17 Introduction 19 Rails Simply Feels Right ......................... 19 Rails Is Agile ............................... 21 Who This Book Is For .......................... 22 How To Read This Book ......................... 22 Part I—Getting Started 26 1 Installing Rails 27 1.1 Installing on Windows ...................... 27 1.2 Installing on Mac OS X ..................... 29 1.3 Installing on Linux ........................ 30 1.4 Choosing a Rails Version .................... 31 1.5 Setting Up Your Development Environment . 32 1.6 Rails and Databases ....................... 36 1.7 What We Just Did ........................ 37 Prepared exclusively for Anton Fonarev CONTENTS 6 2 Instant Gratification 38 2.1 Creating a New Application ................... 38 2.2 Hello, Rails! ............................ 40 2.3 Linking Pages Together ..................... 47 2.4 What We Just Did ........................ 49 3 The Architecture of Rails Applications 51 3.1 Models, Views, and Controllers . 51 3.2 Rails Model Support ....................... 54 3.3 Action Pack: The View and Controller . 56 4 Introduction to Ruby 58 4.1 Ruby Is an Object-Oriented Language . 58 4.2 Data Types ............................ 60 4.3 Logic ................................ 63 4.4 Organizing Structures ...................... 66 4.5 Marshaling Objects ....................... 69 4.6 Pulling It All Together ...................... 69 4.7 Ruby Idioms ........................... 70 Part II—Building an Application 73 5 The Depot Application 74 5.1 Incremental Development .................... 74 5.2 What Depot Does ......................... 75 5.3 Let’s Code ............................. 79 6 Task A: Creating the Application 81 6.1 Iteration A1: Creating the Products Maintenance Applica- tion ................................. 81 6.2 Iteration A2: Making Prettier Listings . 88 7 Task B: Validation and Unit Testing 95 7.1 Iteration B1: Validating! ..................... 95 7.2 Iteration B2: Unit Testing of Models . 100 8 Task C: Catalog Display 109 8.1 Iteration C1: Creating the Catalog Listing . 109 8.2 Iteration C2: Adding a Page Layout . 112 8.3 Iteration C3: Using a Helper to Format the Price . 116 8.4 Iteration C4: Functional Testing of Controllers . 117 Report erratum Prepared exclusively for Anton Fonarev this copy is (B13.0 printing, February 2, 2011) CONTENTS 7 9 Task D: Cart Creation 121 9.1 Iteration D1: Finding a Cart . 121 9.2 Iteration D2: Connecting Products to Carts . 122 9.3 Iteration D3: Adding a Button . 124 10 Task E: A Smarter Cart 130 10.1 Iteration E1: Creating a Smarter Cart . 130 10.2 Iteration E2: Handling Errors . 135 10.3 Iteration E3: Finishing the Cart . 138 11 Task F: Add a Dash of Ajax 143 11.1 Iteration F1: Moving the Cart . 144 11.2 Iteration F2: Creating an Ajax-Based Cart . 149 11.3 Iteration F3: Highlighting Changes . 152 11.4 Iteration F4: Hiding an Empty Cart . 154 11.5 Testing Ajax Changes . 158 12 Task G: Check Out! 163 12.1 Iteration G1: Capturing an Order . 163 12.2 Iteration G2: Atom Feeds . 177 12.3 Iteration G3: Pagination . 181 13 Task H: Sending Mail 186 13.1 Iteration H1: Sending Confirmation Emails . 186 13.2 Iteration H2: Integration Testing of Applications . 193 14 Task I: Logging In 199 14.1 Iteration I1: Adding Users . 199 14.2 Iteration I2: Authenticating Users . 207 14.3 Iteration I3: Limiting Access . 213 14.4 Iteration I4: Adding a Sidebar, More Administration . 216 15 Task J: Internationalization 221 15.1 Iteration J1: Selecting the Locale . 222 15.2 Iteration J2: Translating the Storefront . 224 15.3 Iteration J3: Translating Checkout . 231 15.4 Iteration J4: Add a Locale Switcher . 237 16 Task K: Deployment and Production 241 16.1 Iteration K1: Deploying with Phusion Passenger and MySQL 243 16.2 Iteration K2: Deploying Remotely with Capistrano . 248 16.3 Iteration K3: Checking Up on a Deployed Application . 254 Report erratum Prepared exclusively for Anton Fonarev this copy is (B13.0 printing, February 2, 2011) CONTENTS 8 17 Depot Retrospective 258 17.1 Rails Concepts . 258 17.2 Documenting What We Have Done . 261 Part III—Rails in Depth 263 18 Finding Your Way Around Rails 264 18.1 Where Things Go . 264 18.2 Naming Conventions . 272 19 Active Record 277 19.1 Defining your Data . 277 19.2 Locating and Traversing Records . 282 19.3 Creating, Reading, Updating, and Deleting (CRUD) . 285 19.4 Participating in the Monitoring Process . 301 19.5 Transactions . 308 20 Action Dispatch and Action Controller 313 20.1 Dispatching Requests to Controllers . 313 20.2 Processing of Requests . 324 20.3 Objects and Operations That Span Requests . 335 21 Action View 345 21.1 Using Templates . 345 21.2 Generating Forms . 347 21.3 Processing Forms . 350 21.4 Uploading Files to Rails Applications . 352 21.5 Using Helpers . 355 21.6 Reducing Maintenance with Layouts and Partials . 362 22 Caching 371 22.1 Page Caching . 371 22.2 Expiring Pages . 374 22.3 Fragment Caching . 380 23 Migrations 386 23.1 Creating and Running Migrations . 386 23.2 Anatomy of a Migration . 389 23.3 Managing Tables . 393 23.4 Advanced Migrations . 397 23.5 When Migrations Go Bad . 401 23.6 Schema Manipulation Outside Migrations . 402 Report erratum Prepared exclusively for Anton Fonarev this copy is (B13.0 printing, February 2, 2011) CONTENTS 9 24 Nonbrowser Applications 404 24.1 A Stand-Alone Application Using Active Record . 404 24.2 A Library Function Using Active Support . 405 24.3 A Remote Application Using Active Resource . 410 25 Rails’ Dependencies 416 25.1 Generating XML with Builder . 416 25.2 Generating HTML with ERb . 418 25.3 Managing Dependencies with Bundler . 420 25.4 Interfacing with the Web Server with Rack . 422 25.5 Automating Tasks with Rake . 426 25.6 Survey of Rails’ Dependencies . 427 26 Rails Plugins 431 26.1 Credit Card Processing with Active Merchant . 431 26.2 Saving Bandwidth with Asset Packager . 433 26.3 Beautifying Our Markup with Haml . 435 26.4 Write Less and Do More with JQuery . 438 26.5 Finding More at RailsPlugins.org .