Gain insights into building scalable backend applications with Elixir, OTP, and Phoenix. Learn about persistent connections via Phoenix Channels, and explore distinct, decoupled application layers.

Functional Web Development with  Elixir, OTP and Phoenix by The Pragmatic Programmer_ .png

elixir_islands_test.tar.gz

elixir-app

pheonix-app

elixir-app-guesses

island-interface

phoenix-app-compiled

phoenix-app-iex

phoenix-app-form

phoenix-app-new-module

client-connection

presence

phoenix-app-final

without-presence

Elixir and OTP provide exceptional tools to build rock-solid backend applications that scale. In this course, you’ll build a web application in a radically different way, with a backend that holds application state. You’ll use persistent Phoenix Channel connections instead of HTTP’s request-response, and create the full application in distinct, decoupled layers.

In Part 1, you’ll start by building the business logic as a separate application, without Phoenix. You’ll model the application domain with Elixir functions and simple data structures.

In Part 2, you’ll add in the GenServer Behaviour to make managing in-memory state a breeze. 

In Part 3, you’ll build a web interface with Phoenix where you’ll use Phoenix Channels to establish persistent connections between the stateful server and a stateful front-end client.

Needless to say, you’re going to love this way of building web apps!

Functional Web Development with Elixir, OTP and Phoenix

We want each new game to be supervised. That means that we need the `GameSupervisor` process to start them. As the `GameSupervisor` process starts new game processes, it will link to them and trap exits so it can receive ordinary messages if any game should crash.

## Changes to the `GameSupervisor` module
Let’s start by adding a public `start_game/1` function in the `GameSupervisor` module to the start games. Once we have the supervisor starting the processes, it will take care of the rest:
```Elixir
def start_game(name), do:
  Supervisor.start_child(__MODULE__, [name])
```

We want each new game to be supervised. That means that we need the `GameSupervisor` process to start them. As the `GameSupervisor` process starts new game processes, it will link to them and trap exits so it can receive ordinary messages if any game should crash.

# Changes to the `GameSupervisor` module
Let’s start by adding a public `start_game/1` function in the `GameSupervisor` module to the start games. Once we have the supervisor starting the processes, it will take care of the rest:
```Elixir
def start_game(name), do:
  Supervisor.start_child(__MODULE__, [name])
```

Understand the process of starting and stopping the child processes.

Introduction

Mapping Our Route

Model Data and Behavior

Working of State Machines

Add OTP for Concurrency and Fault Tolerance

Process Supervision for Recovery

Generate a New Web Interface with Phoenix

Create Persistent Connections with Phoenix Channels

Appendix

Start and Stop Child Processes

Changes to the `GameSupervisor` module