Phoenix - OpenCode XXII

phoenix-web-framework.md

Phoenix - Elixir Web framework

by

Simon Prévost, Développeur Web chez Mirego

(The slides were made for mdp)

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Index

• Elixir?!
• Standard framework features
• Not so standard features

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Elixir!

• Compile to Erlang VM
• Functional
• Meta-programming
• Easy mapping for common tools in Erlang
• OTP

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No time for questions!

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• Routers/Controllers
• No models. (Whaaaat?)
• Views
• Templates

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Routers/Controllers

• Plug-based
• Pattern match for routes
• Pattern match for params

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Routers/Controllers

Plug

Definition from Plug’s GitHub repository:

A specification for composable modules in between Web applications Connection adapters for different Web servers in the Erlang VM

Also:

Direct interface to the underlying Web server.

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Routers/Controllers

Pattern match for routes

resources "/users", UserController

get  "/users",          UserController, :index
get  "/users/:id",      UserController, :show
get  "/users/new",      UserController, :new
post "/users",          UserController, :create
get  "/users/:id/edit", UserController, :edit
put  "/users/:id",      UserController, :update
patch "/users/:id",     UserController, :update
delete "/users/:id",    UserController, :destroy

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Routers/Controllers

Pattern match for routes/2

def match(conn, "GET",    ["users"])
def match(conn, "GET",    ["users", id])
def match(conn, "PUT",    ["users", id])
def match(conn, "PATCH",  ["users", id])
def match(conn, "DELETE", ["users", id])

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Routers/Controllers

Pattern match for params

defmodule App.UserController do
  use Phoenix.Controller

  before_action :authenticate

  def show(conn, %{"id" => id}) do
    json conn, "{\"user_id\": \"#{id}\"}"
  end
end

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View

• Render template

• Aka presentor/helper

  defmodule App.UserView do use App.Views

  def display(something) do
    String.upcase(something)
  end
  

  end

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Template

• Precompiled!

• Eex, Haml and easily extensible

  def render(conn, "index.html") do """ ... """ end

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• WebSockets
• Distributed

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WebSockets

• Topics
• Channels

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WebSockets

Topics

PubSub layer used by channels, more on that later ;)

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WebSockets

Channels

defmodule App.MyChannel do
  use Phoenix.Channel

    def event(socket, "incoming:all", message) do
      broadcast socket "response:event", %{message: "Echo: " <> message.content}
      socket
    end
  end
end

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Distributed

(This is not yet implemented)

• Inspired by riak_core
• Distributed Web framework using the Erlang VM

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Distributed

(This is not yet implemented, pseudo-code)

Example:

defmodule App.UserController do
  use Phoenix.Controller

  before_action :authenticate

  def show(conn, %{"id" => "me"}) do
    json conn, JSON.encode!(conn.assigns[:current_user])
  end

  def authenticate(conn) do
    conn
    |> assign(:current_user, Service.call(conn, Authenticator, %{"bearer": "1"}))
  end
end

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Conclusion

Elixir is awesome

Erlang VM is awesom(er)

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Questions?