Tony Messias Maceió DEV Meetup #21 Phoenix for Laravel developers 

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This is not a hands-on talk. 

I'm not going to teach you Elixir (or Phoenix) in 30~ish minutes. 

I'm not saying that one is better than the other. 

In fact, I'm actually showing that you can build shiny things with tools you already know. 

This talk in a mind-map. 

Functional Programming 

Functional Programming 

Haven't the Gods of programming decided that OOP has won this battle? 

Why is functional programming in such a “hype” now? 

What is a function? ● In math, functions are all about transforming input to output (sounds familiar?) ● You might be used to expressing functions in math like so: y = x * 2 or g = x ^ 2 ● But there is another notation that is much more expressive (IMO): f(x) = x * 2 f(5) = 5 * 2 f(5) = 10 

f(x) = x * 2 --- const f = (x) => x * 2 var x = 5 assertEquals(f(x), 10) assertEquals(f(x), f(x)) source 

class Value { constructor(val) { this.value = val; } } const f = (x) => x.value++ * 2 const x = new Value(5); console.log(f(x) == f(x)); // True or False? console.log(x.value); // What is the value? 

class Value { constructor(val) { this.value = val; } } const f = (x) => x.value++ * 2 const x = new Value(5); console.log(f(x) == f(x)); // false console.log(x.value); // 7 

Immutability ease distributing computation. 

Concurrency and Parallelism 

Parallelism Concurrency source 

before I forget... 

Slack'ish in Laravel tonysm/slackish-laravel Slack'ish in Phoenix tonysm/slackish-phoenix 

Elixir, the good parts 

defmodule SlackishphxWeb.CompanyController do use SlackishphxWeb, :controller plug SlackishphxWeb.Plugs.RequireAuth def create(conn, %{"company" => params}) do case Slackishphx.Auth.create_company(conn.assigns[:user], params) do {:ok, company} -> conn |> create_default_channel(company) |> switch_company(conn.assigns[:user], company) {:error, changeset} -> conn |> render("new.html", changeset: changeset) end end end 

defmodule SlackishphxWeb.CompanyController do use SlackishphxWeb, :controller plug SlackishphxWeb.Plugs.RequireAuth def create(conn, %{"company" => params}) do case Slackishphx.Auth.create_company(conn.assigns[:user], params) do {:ok, company} -> conn |> create_default_channel(company) |> switch_company(conn.assigns[:user], company) {:error, changeset} -> conn |> render("new.html", changeset: changeset) end end end 

defmodule SlackishphxWeb.CompanyController do use SlackishphxWeb, :controller plug SlackishphxWeb.Plugs.RequireAuth def create(conn, %{"company" => params}) do case Slackishphx.Auth.create_company(conn.assigns[:user], params) do {:ok, company} -> conn |> create_default_channel(company) |> switch_company(conn.assigns[:user], company) {:error, changeset} -> conn |> render("new.html", changeset: changeset) end end end 

Phoenix, the good parts 

MVC 

Phoenix is not your application. 

slackishphx/lib ├── slackishphx │ ├── application.ex │ ├── auth │ │ ├── auth.ex │ │ ├── company.ex │ │ └── user.ex │ ├── chat │ │ ├── channel.ex │ │ └── chat.ex │ └── repo.ex ├── slackishphx.ex ├── slackishphx_web │ ├── channels │ ├── controllers │ ├── endpoint.ex │ ├── gettext.ex │ ├── plugs │ ├── router.ex │ ├── templates │ └── views └── slackishphx_web.ex 

slackishphx/lib ├── slackishphx │ ├── application.ex │ ├── auth │ │ ├── auth.ex │ │ ├── company.ex │ │ └── user.ex │ ├── chat │ │ ├── channel.ex │ │ └── chat.ex │ └── repo.ex ├── slackishphx.ex ├── slackishphx_web │ ├── channels │ ├── controllers │ ├── endpoint.ex │ ├── gettext.ex │ ├── plugs │ ├── router.ex │ ├── templates │ └── views └── slackishphx_web.ex 

slackishphx/lib ├── slackishphx │ ├── application.ex │ ├── auth │ │ ├── auth.ex │ │ ├── company.ex │ │ └── user.ex │ ├── chat │ │ ├── channel.ex │ │ └── chat.ex │ └── repo.ex ├── slackishphx.ex ├── slackishphx_web │ ├── channels │ ├── controllers │ ├── endpoint.ex │ ├── gettext.ex │ ├── plugs │ ├── router.ex │ ├── templates │ └── views └── slackishphx_web.ex 

Phoenix Channels 

http://phoenixframework.org/blog/the-road-to-2-million-websocket-connections 

Ecto 

defmodule Slackishphx.Auth.User do use Ecto.Schema # ... schema "users" do field :name, :string field :email, :string field :google_id, :string field :google_token, :string field :avatar_path, :string belongs_to :current_company, Company has_many :companies, Company, foreign_key: :owner_id timestamps() end end 

defmodule Slackishphx.Auth.User do # ... @doc false def register_from_google_changeset(%User{} = user, attrs) do user |> cast(attrs, [:name, :email, :google_id, ...]) |> validate_required([:name, :email, ...]) end end 

defmodule Slackishphx.Auth do @moduledoc """ The Auth context. """ def create_company(%User{} = user, params) do changeset = user |> build_assoc(:companies) |> Company.create_company_changeset(params) Repo.insert(changeset) end end 

The not so good parts... 

deployment source 

Comparisons* 

Comparison Laravel (PHP) Phoenix (Elixir) Webapp (sessions) API (everything needs to go through HTTP) Pusher (websockets) Worker (broadcasting is delivered here) Database (sqlite) Queue Webapp (sessions) Channels (websockets) Database (sqlite) 

Some similarities broadcast(new NewMessage( $request->user(), $channel, $request->input('content'), $request->input('uuid'), Carbon::now() )); broadcast!(socket, "rooms:#{room_id}:new", %{ message: message, user: user, uuid: uuid, time: DateTime.utc_now } ) 

Improvement points to Laravel Broadcast::channel('App.User.{id}', function ($user, $id) { return (int) $user->id === (int) $id; }); Broadcast::channel('channels.{channel}', function (\App\User $user, \App\Channel $channel) { if (!$channel->exists || !$user->canJoin($channel)) { return false; } $user->joinChannel($channel); return [ 'id' => $user->id, 'name' => $user->name, 'avatar_path' => $user->avatar_path, ]; }); channel "companies:*", SlackishphxWeb.CompanyChannel channel "rooms:*", SlackishphxWeb.RoomChannel 

That's it! 

References ● Functional Programming; What? Why? When? (Robert C Martin) https://www.youtube.com/watch?v=7Zlp9rKHGD4 ● Real World Elixir Deployment (Pete Gamache) https://www.youtube.com/watch?v=H686MDn4Lo8 ● Erlang: The Movie https://www.youtube.com/watch?v=xrIjfIjssLE ● Lonestar ElixirConf 2017- KEYNOTE: Phoenix 1.3 by Chris McCord https://www.youtube.com/watch?v=tMO28ar0lW8 ● GOTO 2016 • Phoenix a Web Framework for the New Web • José Valim https://www.youtube.com/watch?v=bk3icU8iIto 

References ● ElixirConf 2016 - Giving up the Object-Oriented Ghost by Morgan Lanco https://www.youtube.com/watch?v=_VpZ6gQsyDY ● GOTO 2017 • Elixir: The only Sane Choice in an Insane World • Brian Cardarella https://www.youtube.com/watch?v=gom6nEvtl3U ● Elixir, quem é esse pokemon? - Bruno Volcov https://www.youtube.com/watch?v=aA-XHI-EYcM ● Ecto, você sabe o que é? - Amanda Sposito https://www.youtube.com/watch?v=hQM4VdEpz6g ● Programming Phoenix (book) by Chris McCord, Bruce Tate, and José Valim https://pragprog.com/book/phoenix/programming-phoenix