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

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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

## Communication between the players

Now, let’s look at how `push/3` works inside the `GameChannel`. Instead of a reply tuple, this will send a new event down the Channel, but only to the original caller. Since we don’t rely on a reply tuple to communicate back to the client, we replace it with `{:noreply, socket}`.

The path of message passing will look the same as the reply shown in the following figure.

Let’s go to the Channel and change the `handle_in/3` clause to use `push/3`. We could leave the `:reply` tuple there and get two responses. However, since `push/3` will already send a reply, it makes more sense to swap in `{:noreply, socket}` instead:

# Communication between the players

Now, let’s look at how `push/3` works inside the `GameChannel`. Instead of a reply tuple, this will send a new event down the Channel, but only to the original caller. Since we don’t rely on a reply tuple to communicate back to the client, we replace it with `{:noreply, socket}`.

The path of message passing will look the same as the reply shown in the following figure.

Let’s go to the Channel and change the `handle_in/3` clause to use `push/3`. We could leave the `:reply` tuple there and get two responses. However, since `push/3` will already send a reply, it makes more sense to swap in `{:noreply, socket}` instead:

Understand how both players communicate in Islands’ engine.

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

Communication Between Players

Communication between the players