Component-Based Rails Applications
Component-Based Rails Applications
Large Domains Under Control
About the Book
As Rails applications grow and mature the help we get from the framework shrinks - to some, it even feels like the framework gets in the way. It doesn't need to be that way! With component-based applications we have a great way to control the complexity of our domain. In areas where Rails alone does not lend much support, we look to proven patterns to create a meaningful support structure for all of our applications.
With this book you will learn
- How to create components with gems and engines.
- How to spot and fix common technical issues
- What refactorings to use to tease out new components
- How to extract your first component from any existing project
- How to apply component-based design together with the hexagonal and DCI architectural patterns
You will hear from others that have taken the journey and how they used components to improve their projects.
As you will learn through this book, components are also a great stepping stones towards micro-service architectures.
The intent of this book goes well beyond Rails: We want you to become a better software engineer. Components are a proven method of software development and all popular programming languages allow the creating of components in some way. The learnings from this book will improve your ability to create maintainable applications in any language!
Table of Contents
1.1 Component-Based Rails
- 1.1.1 What Is It?
- 1.1.2 History Repeating?
- 1.2 Component-Based Ruby
- 1.3 The Application Continuum
1.4 What This Book Does not Cover
- 1.4.1 Ruby and Rails Basics
- 1.4.2 Rails 2
- 1.5 Related Works
- 1.6 Structure of This Book
- 1.1 Component-Based Rails
2. Introducing the First Component
- 2.1 How Do I Start Writing a CBRA App?
2.2 Plain vs
--mountableEngines - Which Command Line Options Should I Use for Engine Creation?
- 2.2.1 Plain Plugin
- 2.2.2 Full Engine
- 2.2.3 Mountable Engine
- 2.3 How do Engine Routes and Engine Mounting Work?
2.4 How Do I Handle Migrations Inside of a Component?
- 2.4.1 Installing Engine Migrations With Rake
- 2.4.2 Loading Engine Migrations in Place
- 2.4.3 Known Issues
2.5 How Do I Handle Dependencies in My CBRA App?
2.5.1 Adding a Different Templating Library:
slim(Adding a Regular Gem)
- 2.5.2 Locking Down Gem Versions
2.5.3 Adding the Rating Calculation Library:
trueskill(Adding the Development Version of a Gem)
2.5.4 Adding a Different Testing Framework:
rspec-rails(Adding Development Dependencies)
- 2.5.1 Adding a Different Templating Library:
2.6 How Do I Test My Component?
- 2.6.1 ActiveRecord Model Specs
- 2.6.2 Non-ActiveRecord Model Specs
- 2.6.3 Controller Specs
- 2.6.4 Helper Spec
- 2.6.5 View Specs
- 2.6.6 Routing Specs
- 2.6.7 Feature Specs
2.7 How Do I Test the Main Application?
- 2.7.1 What to Test in the Main App
- 2.7.2 How to Put Everything Together
- 2.7.3 How to Set Up a Continuous Integration (CI) Server
2.8 How Do I Load Component Assets Properly?
- 2.8.1 Production-Ready Assets
- 2.9 How to set up databases with engines?
2.10 How Do I Deploy to Production?
- 2.10.1 Deploying to Heroku
- 2.10.2 Deploying to Pivotal Web Services
2.11 How Do I Update My Application’s Dependencies?
- 2.11.1 Updating the Bundle in All Components
- 2.11.2 Updating Every Component’s Gem Version
- 2.11.3 Updating Rails
- 2.11.4 Long Running Dependency Updates
- 2.11.5 Listing a Dependency Only Once
2.12 How Do I Make it More Clear That This App is Different?
- 2.12.1 Why Would I Want to Change That?
- 2.12.2 How CBRA Can Change How I Present and Perceive My App
- 2.12.3 Making CI and PaaS Work With the New Structure
- 2.12.4 What is Next?
3. From One Component to Many Components
3.1 Why Would I Ever Add Another Component?
- 3.1.1 Improved Communication
- 3.1.2 Improved Collaboration
- 3.1.3 Improved Creation
- 3.1.4 Improved Maintenance
- 3.1.5 Improved Comprehension
- 3.2 Determining What to Extract - Bottum-up
3.3 Refactoring: Extract Domain Gem -
3.3.1 Fixing Inside-out - Making
- 3.3.2 Last Step: Ensure That the App Works
- 3.3.3 Summary of Bottom-Up Component Extractions
- 3.3.1 Fixing Inside-out - Making
3.4 Determining What to Extract - Top-down
- 3.4.1 Unclear dependency direction
- 3.4.2 Not everything needs the predictor
- 3.4.3 Implications of the first set of extractions
- 3.4.4 Problem with the current solution
- 3.4.5 Reducing needed dependencies
3.5 Refactoring: Pulling Up a UI Component -
- 3.5.1 Generate
- 3.5.2 Move
- 3.5.3 Fix, part 1: Reusing test helpers
- 3.5.4 Fix, part 2: Routing issues
- 3.5.5 Fix, part 3: The container application
3.6 Refactoring: Pushing Down a Model Component -
- 3.6.1 Getting Away With Less
- 3.6.3 Fixing Everything Else
3.7 Refactoring: Improve Naming of Component -
3.7.1 Whatever Happened to
- 3.7.2 Refactoring Component Names
- 3.7.3 Refactoring a Component Name Throughout the Application
- 3.7.4 An Even More Mechanical Approach
- 3.7.1 Whatever Happened to
3.8 More Component Refactoring Patterns
- 3.8.1 Splitting One Component in Two: Disentangling Unrelated Concepts
- 3.8.2 API Component
- 3.8.3 3rd Party Service Adapter
- 3.8.4 Common functionality component
- 3.1 Why Would I Ever Add Another Component?
4. From Ball Of Mud to First Components
- 4.1 Small Steps
4.2 One Big Step
- 4.2.1 Prerequisites
- 4.2.2 Script This!
- 4.2.3 A Scripted Refactoring
4.2.4 Cleaning Up
- 4.2.6 Summary
5. Component-based Rails in relation to other patterns
5.1 Hexagonal Architecture
- 5.1.1 Hexagonal Architecture and CBRA
- 5.1.2 Implementing Hexagonal Rails with CBRA
- 5.1.3 Teasing out an adapter in the frontend
- 5.1.4 A repository for data storage
- 5.1.5 Swappable data storage
- 5.1.6 Summary
5.2 Data-Context-Integration (DCI)
- 5.2.1 DCI and CBRA
- 5.2.2 Implementing DCI with CBRA
- 5.2.3 Summary
- 5.1 Hexagonal Architecture
6. Case Studies
6.1 Using components for good object-oriented design — Ryan Platte
- 6.1.1 About me
- 6.1.2 Without packages, you have a mess
- 6.1.3 A clean way to juggle integrations
- 6.1.4 Approaching the transition gradually
- 6.1.5 Depending only on the domain
- 6.1.6 Shell commands
- 6.1.7 Moving into a new business
- 6.1.8 Our experiences
6.2 Stories of Engines — Benjamin Lee Smith
- 6.2.1 Intro
- 6.2.2 Engines Project #1: The from-scratch-rebuild
6.3 Using components to deploy parts of a Rails applications — Enrico Teotti
- 6.3.1 About me
- 6.3.2 A straightforward evolving application
- 6.3.3 Let’s join the SOA wagon!
- 6.3.4 Let’s share Engines on a private gemserver!
- 6.3.5 Component based with local gems and Engines
- 6.1 Using components for good object-oriented design — Ryan Platte
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