A Brief Introduction to Elixir and Phoenix

In this book, we'll walk through the process of building a functional prototype of a social web application that will rely on real-time data updates. If you've ever used any sort of live voting application out there (such as Straw Poll or Twitter Polls), then you're probably pretty comfortable with the idea already. If not, I'll summarize our application so that you know what you're going to be building throughout this book.

Our application will allow users to register for new accounts on our site. From there, they will have the option to create new polls for other users (either while logged in or anonymously) to vote on. We want to make sure that the votes for the polls are recorded and broadcast out to anyone watching the polls in real-time, so we'll take advantage of Phoenix's built-in channel support to provide this.

In addition, our application will allow users to create chat rooms that will be displayed alongside the poll. After they've voted, users will be allowed to chat and discuss the results live as the votes come in. Users will also be allowed to post images, which will be processed,  and uploaded to S3.

Users who create polls will be able to decide who is allowed to vote on their polls; for example, either only logged-in users or any user. Users will be able to modify their polls until they go live.

Users who own the polls should be able to participate in real-time discussions with the people voting on and viewing their polls, including anonymous users. Being able to communicate with each other takes advantage of some of the more advanced real-time concepts that are powering Elixir behind-the-scenes and running separately from the main web portion of our Phoenix application. These concepts demonstrate how we can build larger and more performance-intensive applications!

Now, before we really dive into developing this application, we'll need to make sure we understand some of the tools that are going to help us build this application. The assumption is that you're coming into this with an existing understanding of Elixir, but if not, we will briefly cover some core Elixir concepts while also learning about a tool that will be critical for building a great application in Elixir: the IEx shell and the debugger!

To recap, in this chapter we will cover the following topics:

• Basic Elixir concepts
• The interactive Elixir shell, IEx
• Installing Phoenix
• Creating a new Phoenix project with Mix tasks
• An introduction to the Phoenix project structure