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All LessonsFree Lessons (4)

Building Our Project in Layers

Who Should Take this Course and Why?Introduction to Building Projects Reimagining Design Choices Choosing Our Layers Thinking Before We Start Beginning with the Right Datatypes Creating a Mix project Building Our Functional Core Establishing Our Boundaries OTP, State, and the Functional Core Testing Our Code Planning Our Lifecycle Invoking Our Workers Summary: Building Our Project in Layers Quiz: Layering System for Designing Applications in Elixir

Knowing Our Elixir Datatypes

Introduction to Datatypes Primitive Types Lists Streams Maps and Structs Uses of Maps Map Traps Strings String Representation in Elixir Tuples Functions as Data When to Leave Elixir Summary: Knowing Our Elixir Datatypes Quiz: Data Types that Underpin Elixir

Starting With the Right Data Layer

Introduction to the Data Layer Access Patterns Shape Data Structures A Different Approach Immutability Drives Everything Functional Data Structures Creating Our Mastery Project Identifying the Data of Our Project Identifying the Data of Our Project—Continued Summary: Starting with the Right Data Layer Quiz: Data Layers in Elixir

Building Our Functional Core

Introduction to Our Functional Core Organize Core Functions by Purpose Commencing Our Quizzes Functions are Data Naming Concepts with Functions Composing a Quiz from Functions Building Single Purpose Functions Building at a Single Level of Abstraction Moving Our Tokens Through Transformations Keeping the Left Margin Skinny Trying Out the Core Summary: Building Our Functional Core Quiz: Building Functional Cores

Testing Our Core

Introduction to Writing Tests Simplifying Tests with Common Setup Functions Improving the ExUnit Infrastructure Providing Test Data with Fixtures Building Our Quizzes Using Fixture Functions Directly Prime Tests with Named Setups Applying Named Setup Functions to Our Tests Making Tests Repeatable Making Tests Repeatable—Continued Composing Within Tests Testing Our Quiz Taking Tests Beyond the Elixir Base Summary: Testing Our Core Quiz: Tests for the Functional Core

Isolating Process Machinery in a Boundary

Introduction to the Boundary Layer

Maintaining Composition Through Uncertainty

Treating Errors as Data

Reporting Successes and Errors

Using with to Compose Uncertain Structures

Building Our Optional Server

Blueprint of Our Boundary Layer

Implementing the QuizManager with Processes

Adding More Functionality to the QuizManager

Trying Out the Quiz Manager

Laying Grounds for QuizSession Implementation

Implementing QuizSession

Test Driving the Quiz Session

Wrapping the Server in an API

Validating Our Quizzes

Validating Our Templates

Building the API Layer

Test Driving the API

Configuring Options

Extending our APIs Safely

Summary: Isolating Process Machinery in a Boundary

Quiz: Boundaries and GenServers

Customizing Our Lifecycle

Introduction to the Lifecycle Layer Understanding the Lifecycle Building Blocks Elixir Functions to Manage Processes Starting Processes with Links Configuring Applications to Start Supervisors Creating a start_link Configuring the Application Additional Options to Manipulate Supervisors Starting Per-User Processes with a Dynamic Supervisor Adding a Start Link Using Names to Find Services Adding the Registry and Dynamic Supervisor to application.ex Establishing Supervision Strategies Observing It Running with Multiple Users Summary: Customizing Our Lifecycle Quiz: Supervisors and the Lifecycle Layer

Invoking Our Workers

Introduction to the Worker Layer Knowing Our Motivations Leveraging Workers in Dependencies Making Serial Code Concurrent with Tasks Building Pools of Common Resources with Poolboy Adding a Proctor to Run Timed Quizzes Writing the Proctor Boundary Server Laying Grounds for the Proctor Boundary Server Completing the Implementation of the Proctor Boundary Server Integrating the Proctor into the Boundary — QuizManager Putting the Proctor to Work Summary: Invoking Our Workers Quiz: Workers and Services with Concurrency

Assembling Our Components

Introducing Persistence Adding Persistence as a Boundary Service Managing Persistence with Callbacks Building a Poncho Project Persisting the Responses Establishing an API Building Our Postgres Table Integrating MasteryPersistence into Mastery Integrating a Function to Persist Records Integrating Our OTP Dependencies into Phoenix Integrating Our OTP Dependencies into Phoenix—Continued Organizing Code for OTP Abstractions Adding Layers to Phoenix Channels Adding Layers to LiveView Building Scenic Projects with Layers Summary: Assembling Our Components Quiz: Making Different Dependencies Work Together

Testing the Boundary

Introduction to Testing Our Boundary Tests Call the API as a User Would—Setting Up Tests Call the API as a User Would—Helper Functions Running the Test for Our API Testing Poncho Projects Directly Isolating the Proctor’s Boundary Concerns Modifying the Boundary of the Mastery Project Adding Notifications to Mastery and the Boundary Working with the New Notifications The Final Test for Our Quizzes Summary: Testing the Boundary Quiz: Writing Tests at the Boundary Layer

Designing Elixir Systems with OTP/

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Validating Our Quizzes

Validating Our Quizzes

Let’s learn how to validate our quizzes.

We'll cover the following...

We first need to validate a quiz. We are creating a module per validator, and only add models that take complex user data.

Declaring our module and some core functions

In /lib/mastery/boundary/quiz_validator.ex, we’ll write this code:

C++

defmodule Mastery.Boundary.QuizValidator do import Mastery.Boundary.Validator
  def errors(fields) when is_map(fields) do 
    [ ]
    |> require(fields, :title, &validate_title/1)
    |> optional(fields, :mastery, &validate_mastery/1) 
  end
  def errors(_fields), do: [{nil, "A map of fields is required"}]

We have a core errors function that does the lion’s share of the work.

We have only two fields that have external input, an optional :mastery field and a required :title field.
We pipe through those and return the responses. ...