17. Elixir: Phoenix

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A Peek at Phoenix in Elixir

Creating the Phoenix App

Here’s how to generate the scaffold Phoenix app we walked through in the video:

Step 1: Install Hex

Start by installing Hex (Elixir’s package manager) locally:

mix local.hex

If you already have a version of Hex installed, you’ll be asked whether you want to upgrade Hex to the latest version.

Step 2: Install the Phoenix Archive

Next, install the Phoenix archive:

mix archive.install hex phx_new 1.5.1

Step 3: Create a Phoenix Project

With Phoenix successfully installed, you can now create a Phoenix project. We named our project refuge:

mix phx.new refuge

You’ll see a list of files and directories created by the generator in a new refuge parent directory. Change into the refuge directory:

cd refuge

Step 4: Generate the Scaffold HTML App

Generate the scaffold HTML app using the phx.gen.html generator:

mix phx.gen.html Wildthings Bear bears name:string type:string hibernating:boolean

After running this command, open the refuge directory in your favorite editor to see all the code!

Route vs. Match Functions

Our route function currently takes one argument: a map representing the conversation. We pattern match the key-value pairs in the map. For example, here’s the route that matches a GET request for the path /bears:

def route(%Conv{ method: "GET", path: "/bears" } = conv) do
  ...
end

By comparison, here’s the match function generated by Phoenix:

def match(conn, "GET", ["/bears"]) do
  ...
end

Notice it takes three arguments: conn (which is similar to our conversation map), the HTTP verb, and a list containing path segments.

Comparison to Our Route Design

Earlier in the course, our route/1 function looked very similar to the match function generated by Phoenix. We had a route/1 function that called a route/3 function:

def route(conv) do
  route(conv, conv.method, conv.path)
end

And here’s the route/3 function that matched a GET request for the path /bears:

def route(conv, "GET", "/bears") do
  ...
end

This is strikingly similar to the match function generated by Phoenix. The primary difference is that match takes a list of path segments as its third argument, which provides more information for pattern matching.

Experimenting with Designs

One of the reasons we chose a single map argument for the route function was to learn how to pattern match maps. However, now that you have seen both designs, you can experiment and decide which approach works better for you!

Code So Far

The code for this section is in the phoenix directory found within the video-code directory of the code bundle

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