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A New Architecture For Rails

About the Book

Note: This book discusses Trailblazer 1.x. We provide free guides for TRB2 on the website, but the general idea of this book still applies. A new beginner's book is on the way!

Trailblazer is a thin layer on top of Rails and brings a high-level application architecture, decent encapsulation and a new code structure. Here are the main features.

  • Logicless models solely focusing on persistence.
  • Skinny controllers working as endpoints, only.
  • Domain objects for your business logic, known as operations.
  • Form objects for deserialisation and validation.
  • View models to introduce a widget architecture.
  • Representers that parse and render documents for APIs.
  • Twin objects for decorating models.

This book takes you for an adventure trip from Rails' code jungle to Trailblazer beach. We're building a complete Rails application using all of Trailblazer's goodies while exploiting the Rails Way where it helps us.

What we build here is not just a simple 5-minutes blog, but a full-blown commenting application with complex forms, composed views, signed-in users and admin, authentication rules, polymorphic views and operatoins, a document-based JSON API, and more. We have a strong focus on testing, object design and structuring the code using Trailblazer's concept-oriented framework.

2. The Trailblazer Architectural Style

Chapter 2 is a complete overview about all the concepts of Trailblazer, starting from domain objects, integrated form to view models, policies and twins.

3. Operations and Forms

The third chapter gives you everything you need to encapsulate your business logic into operations and building rock-solid domain components using the integrated form. We also learn how to render forms from operations, and how to test both for a good sleep.

4. Cells

We then discuss the principles of Cells view models, how to encapsulate your view into components and the way helpers work in this layer. Learning how to test your rendering and integrating those with smoke tests round up this fine chapter.

5. Nested Forms

Forms can and do represent deeply nested object structures. In this chapter we learn how to nest forms to create more than one model in an operation.

6. Composed Views and AJAX Pagination

Usability, or "UI is king!" is one of Trailblazer's maxims. We walk through advanced Cells features, learn how to embedd forms into existing pages, break Rails' "RESTfulness" and discuss AJAX-backed pagination with Cells.

7. Mastering Forms

Forms are an integral part of Trailblazer. They orchestrate deserialization of input, population and validation. The seventh chapter really dives into Reform, dynamic population, skipping nested items, form inheritance and removing items from collections. We also discuss Non-CRUD behavior and how operation and form work together to expose more than just plain CRUD semantics.

8. Callbacks

Callbacks in Trailblazer no longer sit in one huge model file but get restructured in operations. Sending email notifications, adding and inheriting callbacks, and the structure of operations are the main content of this chapter. A discussion about view caching and expiring those via callbacks will prepare you to write advanced operations.

A section about file uploads will make sure this chapter covers all major parts of post-processing business logic.

9. Authentication

Operations are the perfect place for authentication logic. We will implement sign in, sign up, mail notifications, and many more authentication-related functions in this chapter. Strong tests will make sure only authenticated users get access to certain parts of the application.

You will learn how the Tyrant gem helps implementing authentication workflows without all the pain you've had with Devise.

10. Policies and Authorization

Policies are a technique to restrict users to specific operations and UI elements. But, there's more to it. Using policies and builders, we can use polymorphism to map operations to different contexts, like anonymous users or admins. We'll refine our forms and UI for specific user types in this chapter and learn everything about policies to protect your functions from unauthorized use.

11. Hypermedia APIs: Rendering

Operations in Trailblazer integrate with representers from the Representable/Roar gem. This helps quickly setting up document APIs. This chapter discusses how representers can be inferred, specified and explicitly created to render things, comments, and their associations following the HAL media format.

12. Hypermedia APIs: Deserialization

The hardest part of API code is the deserialization: parsing documents into object graphs. Trailblazer leverages representers to parse incoming documents directly to your operation's contract, and this chapter explains all you got to know to understand every step of it.

About the Author

Nick Sutterer
Nick Sutterer

Nick loves working on open-source frameworks, and that's what he does almost every day. He also loves people, surfing, beer, skateboarding and loud music. Make sure to hug him should you ever meet him in person.

Reader Testimonials

Pedro Visintin
Pedro Visintin

This is punk! Trailblazer breaks with the established MVC dogma. This book has a bigger scope than Ruby and Rails, it's about architecture and good design. Nick made the book easy to read with some condiments of humor and lifestyle.

Jason King
Jason King

The Trailblazer book smacks you in the face with a very well reasoned argument for a new architecture for Rails, Nick escorts the reader to a complete understanding of both the motivation behind Trailblazer and the effective use of it.

Yuri Freire Lima
Yuri Freire Lima

Trailblazer helps organize my code, the book showed me how. It's very easy and intuitive, it should be shipped as an essential part of Rails.

Matthew Heath
Matthew Heath

Trailblazer has saved me from the ninth level of development hell. The book is one of the most well-written technical books I've ever had the pleasure (yes, PLEASURE) of reading. Buy it if you value your time and sanity.

Barrie Hadfield
Barrie Hadfield

CTO of Workshare

Trailblazer does as much for Rails as Ruby did. An amazing book and a fundamentally new way of thinking about RoR. This book is humorous, comforting and packed with insight and pragmatism. A must read for anyone committed to Rails and OO programming.

Nick Gorbikoff
Nick Gorbikoff

Lead Developer

Haven't been this excited about Rails since 2007, Trailblazer - makes Rails development fun again. Especially on big projects. It's one of the better implementations of the ServiceObject / ViewModel / Policy layers I've seen.

Eric Skogen
Eric Skogen

Software Inventor

Trailblazer has brought the fun back to Rails for me. Nick’s years of insight in software architecture have been distilled into this helpful primer, explaining his thought process for organizing real, complex apps. Highly recommended!

Annie Caron
Annie Caron

I searched for a long time to bring my Rails apps to the next level. TRB goes further than classic MVC and helpers - it's exactly how I imagined my structure. The book helped me a lot to understand how Trailblazer works and what the author's thinking. A must read and learn!

Table of Contents

    • Introduction
      • How To Read This Book
      • The Missing Architecture
      • Learnings About Reality
    • The Trailblazer Architectural Style
      • Why Trailblazer?
      • A Non Intrusive Framework
      • Trailblazer In A Nutshell
      • Logicless Models
      • Concepts and File Structure
      • High-Level Domain
      • Operation
      • High-Level Architecture
      • Validations
      • Inheritance Over Configuration
      • Builders
      • Authorization And Policy
      • Authentication
      • Representers
      • API: Parsing and Rendering
      • Using Hypermedia
      • Rendering Views
      • Cells
      • Twin
      • Testing
      • A Note On Complexity
      • Summary
    • Operations And Forms
      • The Example app
      • The Create Operation
      • Controllers
      • Reform: Form Objects
      • Operation’s Form Integration
      • Model Semantics
      • Rendering Forms
      • Testing Validations
      • Testing Controllers: Integration Tests
      • Update Operation
      • Reform and strong_parameters
    • Cells
      • Rails Views and Encapsulation
      • View Models
      • Modelling the UI with Cells
      • Anatomy of a Cell
      • Rendering Collections
      • Integration Tests
      • Cell Tests
      • Nesting Cells
      • Rails and MVC
      • Final Test Setup
      • The cell Helper
      • Summary
    • Nested Forms
      • Adding Comments
      • The Comment Concept
      • The setup_model! Hook
      • Nested Contracts
      • Pre-populating Forms
      • Form Processing
      • Populating Forms for Validation
      • Saving Nested Objects
      • Flash messages and Redirecting
      • Readers for Operations
      • Static Form Population
      • Form Presentation Helpers
      • Pre-selecting Values
      • Operation and Form Tests
    • Composed Views
      • The present Helper.
      • Multiple Operations for Composed Pages
      • Form Submission: Widgets vs. “RESTful”
      • Writing a Cells Feature
      • Application-wide Features
      • Simple Decorator Helpers
      • Rails’ View Architecture
      • Kaminari Pagination and Cells
      • AJAX Pagination with Cells
      • On Controller Structuring
      • Cells Tests
      • Smoke Tests
      • Summary
    • Mastering Forms
      • Things and Authors
      • Adding Authors
      • Dynamic Prepopulation
      • Validation Population
      • Skipping Blanks
      • Form Debugging Techniques
      • Saving
      • Adding Authorships
      • Non-CRUD Behavior
      • Complex Validations
      • Testing Create
      • Presentation Tests
      • Updating Things
      • Hacking the View
      • Helpers in Forms
      • Form Inheritance
      • Virtual Properties
      • Populator
      • Persisting the Deletion
      • Testing Update
      • Extracting Forms to Separate Files
    • Callbacks
      • Domain Callbacks
      • The Persisted Module
      • Explicit Callbacks
      • Imperative Callbacks
      • Callbacks in Operations
      • Testing Callbacks
      • View Caching
      • Cache Keys
      • Expiring Keys
      • Debugging View Caching
      • Caching Composed Views
      • The CacheVersion Pattern
      • File Uploads
      • Paperdragon
      • File Validations
      • Callback Groups
      • Rendering Images
      • Testing Uploads
      • Conclusion
    • Authentication
      • Populating by ID
      • Tyrant
      • Sign Up
      • Authenticatable
      • SignUp Form
      • Testing SignUp
      • Sign In
      • Modelless Forms
      • Login
      • Application-wide Tyrant
      • A Warm Greeting
      • Signing Out
      • Testing Logins
      • Putting Users to Sleep
      • Waking Up Sleeping Users
      • Integration Tests for Wake Up
    • Authorization And Polymorphism
      • Policies
      • Operation Inheritance
      • Polymorphic Builders
      • Resolver
      • Refining Operations with Modules
      • Polymorphic Testing
      • Polymorphic Views
      • Integration Test: Create
      • Updating
      • Composable Operations
      • Update Tests
      • Delete
      • Impersonate
    • Hypermedia APIs: Rendering
      • File Structure
      • Rendering Comments
      • HAL Hypermedia Links
      • Rendering
      • Representer
      • GET Controller
      • Responders
      • Inferring Representer
      • Composing Representer
      • Rendering Nested Documents
      • Scopes and Sorting
      • Index Operation
      • Lonely Collections
      • Filtering
    • Hypermedia APIs: Deserialization
      • Deserialization in Trailblazer
      • Parsing Comment
      • Deserialization and Contract
      • Deserialization in Reform
      • Deserializing HAL
      • Create
      • Polymorphic Update
      • Basic Auth
      • Discussion: Polymorphic Operations and APIs
    • Perspectives
      • This Book
      • Why Not a New Framework?
      • Rails
      • Webmachine
      • Grape
      • ROM
      • Roda
      • Hanami
      • Trailblazer
  • Notes

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