Build your own web framework in Elixir

Do you use Phoenix, but you don’t know how it works underneath the hood? Do you have a nagging feeling that you should know more about the ins and outs of processing a web request and turning it into a rendered page?

Good, then this talk is for you!

Understanding how a web framework turns a request into a rendered page is an important aspect of building web applications. And what better way to learn the fundamentals of how a web framework works than to build one in Elixir? So join me as we build a web framework in Elixir complete with a router, controllers, and templates. We’ll take a look at how Plug has already done most of the work for us and at how we can leverage such a powerful abstraction to extend what it gives us. We’ll even look at how to make our templates render blazingly fast by compiling them into functions.

You may not be ready to bet your business on this new framework, but by the end of the talk, you’ll certainly be better equipped to understand what Phoenix is doing underneath macros and to extend it with new functionality. And hey, if you really want to create a new framework, you’ll get a solid start.

Transcript

1. Build your own web framework
   German Velasco
   @germsvel
   

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2. thoughtbot
   

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3. github.com/
   germsvel/daze
   

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4. Cowboy
   Plug
   EEx
   

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5. Plug's specification
   defmodule Daze.Plug do
   def init(opts), do: opts
   def call(conn, _opts) do
   conn
   end
   end
   

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6. Plug's specification
   defmodule Daze.Plug do
   def init(opts), do: opts
   def call(conn, _opts) do
   conn
   end
   end
   

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7. Plug's specification
   defmodule Daze.Plug do
   def init(opts), do: opts
   def call(conn, _opts) do
   conn
   end
   end
   

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8. Plug's specification
   defmodule Daze.Plug do
   def init(opts), do: opts
   def call(conn, _opts) do
   conn
   end
   end
   

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9. The Basics
   

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10. mix new daze --sup
    

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11. config/
    deps/
    lib/
    test/
    mix.exs
    mix.lock
    

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12. defmodule Daze.Mixfile do
    def application do
    [
    extra_applications: [:logger, :cowboy, :plug],
    mod: {Daze.Application, []}
    ]
    end
    defp deps do
    [
    {:cowboy, "~> 1.1.0"},
    {:plug, "~> 1.4.0"}
    ]
    end
    end
    

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13. defmodule Daze.Mixfile do
    def application do
    [
    extra_applications: [:logger, :cowboy, :plug],
    mod: {Daze.Application, []}
    ]
    end
    defp deps do
    [
    {:cowboy, "~> 1.1.0"},
    {:plug, "~> 1.4.0"}
    ]
    end
    end
    

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14. defmodule Daze.Mixfile do
    def application do
    [
    extra_applications: [:logger, :cowboy, :plug],
    mod: {Daze.Application, []}
    ]
    end
    defp deps do
    [
    {:cowboy, "~> 1.1.0"},
    {:plug, "~> 1.4.0"}
    ]
    end
    end
    

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15. mix deps.get
    

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16. config/
    deps/
    lib/
    daze/
    application.ex
    test/
    mix.exs
    mix.lock
    

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17. defmodule Daze.Application do
    use Application
    def start(_type, _args) do
    children = [
    ]
    opts = [strategy: :one_for_one, name: Daze.Supervisor]
    Supervisor.start_link(children, opts)
    end
    end
    

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18. defmodule Daze.Application do
    use Application
    def start(_type, _args) do
    children = [
    {Plug.Adapters.Cowboy, }
    ]
    opts = [strategy: :one_for_one, name: Daze.Supervisor]
    Supervisor.start_link(children, opts)
    end
    end
    

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19. defmodule Daze.Application do
    use Application
    def start(_type, _args) do
    children = [
    {Plug.Adapters.Cowboy, scheme: :http, }
    ]
    opts = [strategy: :one_for_one, name: Daze.Supervisor]
    Supervisor.start_link(children, opts)
    end
    end
    

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20. defmodule Daze.Application do
    use Application
    def start(_type, _args) do
    children = [
    {Plug.Adapters.Cowboy, scheme: :http, options: [port: 4001]}
    ]
    opts = [strategy: :one_for_one, name: Daze.Supervisor]
    Supervisor.start_link(children, opts)
    end
    end
    

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21. defmodule Daze.Application do
    use Application
    def start(_type, _args) do
    children = [
    {Plug.Adapters.Cowboy, scheme: :http, plug: Daze.Router, options: [port: 4001]}
    ]
    opts = [strategy: :one_for_one, name: Daze.Supervisor]
    Supervisor.start_link(children, opts)
    end
    end
    

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22. config/
    deps/
    lib/
    daze/
    + router.ex
    test/
    mix.exs
    mix.lock
    

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23. defmodule Daze.Router do
    end
    

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24. defmodule Daze.Router do
    use Plug.Router
    end
    

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25. defmodule Daze.Router do
    use Plug.Router
    plug :match
    plug :dispatch
    end
    

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26. defmodule Daze.Router do
    use Plug.Router
    plug :match
    plug :dispatch
    get "/" do
    send_resp(conn, 200, "We have a router!")
    end
    end
    

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27. mix run --no-halt
    

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28. View Slide

29. Are we getting requests?
    

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30. defmodule Daze.Router do
    use Plug.Router
    plug :match
    plug :dispatch
    get "/" do
    send_resp(conn, 200, "We have a router!")
    end
    end
    

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31. defmodule Daze.Router do
    use Plug.Router
    plug Plug.Logger
    plug :match
    plug :dispatch
    get "/" do
    send_resp(conn, 200, "We have a router!")
    end
    end
    

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32. View Slide

33. mix daze.server
    config/
    deps/
    lib/
    mix/
    tasks/
    + daze.server.ex
    test/
    mix.exs
    mix.lock
    

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34. defmodule Mix.Tasks.Daze.Server do
    use Mix.Task
    def run(args) do
    Mix.Tasks.Run.run(args ++ ["--no-halt"])
    end
    end
    

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35. defmodule Mix.Tasks.Daze.Server do
    use Mix.Task
    def run(args) do
    Mix.Tasks.Run.run(args ++ ["--no-halt"])
    end
    end
    

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36. defmodule Mix.Tasks.Daze.Server do
    use Mix.Task
    require Logger
    def run(args) do
    Logger.info("Starting Daze Server")
    Mix.Tasks.Run.run(args ++ ["--no-halt"])
    end
    end
    

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37. View Slide

38. View Slide

39. defmodule Daze.Router do
    use Plug.Router
    if Mix.env() == :dev do
    use Plug.Debugger
    end
    plug Plug.Logger
    plug :match
    plug :dispatch
    get "/" do
    send_resp(conn, 200, "We have a router!")
    end
    end
    

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40. defmodule Daze.Router do
    use Plug.Router
    if Mix.env() == :dev do
    use Plug.Debugger, style: [primary: "#c0392b", accent: "#41B577"]
    end
    plug Plug.Logger
    plug :match
    plug :dispatch
    get "/" do
    send_resp(conn, 200, "We have a router!")
    end
    end
    

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41. View Slide

42. Controllers, Views,
    and Templates
    

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43. Extract
    controller logic
    

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44. defmodule Daze.Router do
    use Plug.Router
    # snip
    get "/" do
    send_resp(conn, 200, "We have a router!")
    end
    end
    

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45. defmodule Daze.Router do
    use Plug.Router
    # snip
    get "/", to: Daze.Actions.Posts.Index
    end
    

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46. config/
    deps/
    lib/
    daze/
    actions/
    posts/
    + index.ex
    test/
    mix.exs
    mix.lock
    

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47. Plugs, remember?
    defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, "Plugs all the way down!")
    end
    end
    

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48. Plugs, remember?
    defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, "Plugs all the way down!")
    end
    end
    

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49. Plugs, remember?
    defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, "Plugs all the way down!")
    end
    end
    

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50. Plugs, remember?
    defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, "Plugs all the way down!")
    end
    end
    

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51. View Slide

52. Templates with
    EEx
    

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53. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, "Plugs all the way down!")
    end
    end
    

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54. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    require EEx
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, "Plugs all the way down!")
    end
    end
    

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55. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    require EEx
    EEx.function_from_file :def, :index
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, "Plugs all the way down!")
    end
    end
    

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56. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    require EEx
    EEx.function_from_file :def, :index, "lib/daze/templates/posts/index.html.eex"
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, "Plugs all the way down!")
    end
    end
    

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57. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    require EEx
    EEx.function_from_file :def, :index, "lib/daze/templates/posts/index.html.eex", [:adjective]
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, "Plugs all the way down!")
    end
    end
    

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58. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    require EEx
    EEx.function_from_file :def, :index, "lib/daze/templates/posts/index.html.eex", [:adjective]
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, index("coolest"))
    end
    end
    

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59. config/
    deps/
    lib/
    daze/
    templates/
    posts/
    + index.html.ex
    test/
    mix.exs
    mix.lock
    

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60. 
    
    
    
    
    EEx is the <%= adjective %>!
    
    
    

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61. 
    
    
    
    
    EEx is the <%= adjective %>!
    
    
    

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62. View Slide

63. 
    
    
    
    
    EEx is the <%= adjective1 %> and the <%= adjective2 %>!
    
    
    

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64. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    require EEx
    EEx.function_from_file :def, :index, "lib/daze/templates/posts/index.html.eex", [:adjective1, :adjective2]
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, index("coolest", "fastest"))
    end
    end
    

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65. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    require EEx
    EEx.function_from_file :def, :index, "lib/daze/templates/posts/index.html.eex", [:assigns]
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, index(adjective1: "coolest", adjective2: "fastest"))
    end
    end
    

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66. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    require EEx
    EEx.function_from_file :def, :index, "lib/daze/templates/posts/index.html.eex", [:assigns]
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, index(adjective1: "coolest", adjective2: "fastest"))
    end
    end
    

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67. 
    
    
    
    
    EEx is the <%= @adjective1 %> and the <%= @adjective2 %>!
    
    
    

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68. View Slide

69. Views
    

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70. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    require EEx
    EEx.function_from_file :def, :index, "lib/daze/templates/posts/index.html.eex", [:assigns]
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, index(adjective1: "coolest", adjective2: "fastest"))
    end
    end
    

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71. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    - require EEx
    - EEx.function_from_file :def, :index, "lib/daze/templates/posts/index.html.eex", [:assigns]
    def init(opts), do: opts
    def call(conn, _opts) do
    send_resp(conn, 200, index(adjective1: "coolest", adjective2: "fastest"))
    end
    end
    

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72. config/
    deps/
    lib/
    daze/
    views/
    + posts.ex
    test/
    mix.exs
    mix.lock
    

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73. defmodule Daze.Views.Posts do
    end
    

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74. defmodule Daze.Views.Posts do
    require EEx
    EEx.function_from_file
    :def,
    :index,
    "lib/daze/templates/posts/index.html.eex",
    [:assigns]
    end
    

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75. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    alias Daze.Views.Posts
    def init(opts), do: opts
    def call(conn, _opts) do
    conn
    |> send_resp(200, Posts.index(adjective1: "coolest", adjective2: "fastest"))
    end
    end
    

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76. defmodule Daze.Actions.Posts.Index do
    import Plug.Conn
    alias Daze.Views.Posts
    def init(opts), do: opts
    def call(conn, _opts) do
    conn
    |> send_resp(200, Posts.index(adjective1: "coolest", adjective2: "fastest"))
    end
    end
    

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77. View Slide

78. Handling forms
    

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79. 
    
    
    
    
    Posts
    
    
    Post:
    
    Author
    
    Post
    
    
    
    
    

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80. 
    
    
    
    
    Posts
    
    
    Post:
    
    Author
    
    Post
    
    
    
    
    

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81. defmodule Daze.Router do
    use Plug.Router
    # snip
    plug Plug.Logger
    plug :match
    plug :dispatch
    get "/", to: Daze.Actions.Posts.Index
    end
    

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82. defmodule Daze.Router do
    use Plug.Router
    # snip
    plug Plug.Logger
    plug :match
    plug Plug.Parsers, parsers: [:urlencoded, :multipart]
    plug :dispatch
    get "/", to: Daze.Actions.Posts.Index
    end
    

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83. conn # =>
    %Plug.Conn{
    query_params: _,
    body_params: _,
    params: _
    }
    

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84. defmodule Daze.Router do
    use Plug.Router
    # snip
    plug Plug.Logger
    plug :match
    plug Plug.Parsers, parsers: [:urlencoded, :multipart]
    plug :dispatch
    get "/", to: Daze.Actions.Posts.Index
    end
    

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85. defmodule Daze.Router do
    use Plug.Router
    # snip
    plug Plug.Logger
    plug :match
    plug Plug.Parsers, parsers: [:urlencoded, :multipart]
    plug :dispatch
    get "/", to: Daze.Actions.Posts.Index
    post "/posts", to: Daze.Actions.Posts.Create
    end
    

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86. config/
    deps/
    lib/
    daze/
    actions/
    posts/
    + create.ex
    test/
    mix.exs
    mix.lock
    

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87. defmodule Daze.Actions.Posts.Create do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    end
    end
    

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88. defmodule Daze.Actions.Posts.Create do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    %{ "post" => post, "author" => author } = conn.params
    end
    

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89. defmodule Daze.Actions.Posts.Create do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    %{ "post" => post, "author" => author } = conn.params
    url = "/"
    end
    end
    

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90. defmodule Daze.Actions.Posts.Create do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    %{ "post" => post, "author" => author } = conn.params
    url = "/"
    conn
    end
    end
    

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91. defmodule Daze.Actions.Posts.Create do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    %{ "post" => post, "author" => author } = conn.params
    url = "/"
    conn
    |> put_resp_header("location", url)
    end
    end
    

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92. defmodule Daze.Actions.Posts.Create do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    %{ "post" => post, "author" => author } = conn.params
    url = "/"
    conn
    |> put_resp_header("location", url)
    |> put_resp_content_type("text/html")
    end
    end
    

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93. defmodule Daze.Actions.Posts.Create do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    %{ "post" => post, "author" => author } = conn.params
    url = "/"
    conn
    |> put_resp_header("location", url)
    |> put_resp_content_type("text/html")
    |> send_resp(302, "You are being redirected to #{url}")
    end
    end
    

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94. defmodule Daze.Actions.Posts.Create do
    import Plug.Conn
    def init(opts), do: opts
    def call(conn, _opts) do
    %{ "post" => post, "author" => author } = conn.params
    Daze.Repo.insert(author, %{body: post, author: author})
    url = "/"
    conn
    |> put_resp_header("location", url)
    |> put_resp_content_type("text/html")
    |> send_resp(302, "You are being redirected to #{url}")
    end
    

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95. config/
    deps/
    lib/
    daze/
    + repo.ex
    test/
    mix.exs
    mix.lock
    

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96. defmodule Daze.Repo do
    use Agent
    end
    

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97. defmodule Daze.Repo do
    use Agent
    def start_link(_) do
    Agent.start_link(fn -> Map.new end, name: __MODULE__)
    end
    end
    

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98. defmodule Daze.Repo do
    use Agent
    # snip
    def insert(key, value) do
    Agent.update(__MODULE__, fn map ->
    data =
    case Map.get(map, key) do
    nil -> []
    values -> values
    end
    Map.put(map, key, [value | data])
    end)
    end
    end
    

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99. defmodule Daze.Repo do
    use Agent
    # snip
    def all do
    Agent.get(__MODULE__, fn map ->
    map
    |> Map.values()
    |> Enum.concat()
    end)
    end
    end
    

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100. defmodule Daze.Application do
     @moduledoc false
     use Application
     def start(_type, _args) do
     children = [
     {Plug.Adapters.Cowboy, scheme: :http, plug: Daze.Router, options: [port: 4001]},
     {Daze.Repo, []}
     ]
     opts = [strategy: :one_for_one, name: Daze.Supervisor]
     Supervisor.start_link(children, opts)
     end
     end
     

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101. defmodule Daze.Actions.Posts.Index do
     import Plug.Conn
     alias Daze.Views.Posts
     def init(opts), do: opts
     def call(conn, _opts) do
     posts = Daze.Repo.all()
     conn
     |> send_resp(200, Posts.index(posts: posts))
     end
     end
     

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102. 
     
     # snip
     <%= if @posts do %>
     
     <%= for post <- @posts do %>
     
     <%= post.body %>
     by <%= post.author %>
     
     <% end %>
     
     <% end %>
     
     
     
     

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103. 
     
     # snip
     <%= if @posts do %>
     
     <%= for post <- @posts do %>
     
     <%= post.body %>
     by <%= post.author %>
     
     <% end %>
     
     <% end %>
     
     
     
     

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104. 
     
     # snip
     <%= if @posts do %>
     
     <%= for post <- @posts do %>
     
     <%= post.body %>
     by <%= post.author %>
     
     <% end %>
     
     <% end %>
     
     
     
     

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105. View Slide

106. View Slide

107. Daze.Action
     

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108. defmodule Daze.Actions.Posts.Index do
     import Plug.Conn
     alias Daze.Views.Posts
     def init(opts), do: opts
     def call(conn, _opts) do
     # snip
     end
     end
     

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109. defmodule Daze.Actions.Posts.Create do
     import Plug.Conn
     def init(opts), do: opts
     def call(conn, _opts) do
     # snip
     end
     end
     

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110. config/
     deps/
     lib/
     daze/
     + action.ex
     test/
     mix.exs
     mix.lock
     

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111. defmodule Daze.Action do
     defmacro __using__(opts) do
     quote do
     end
     end
     end
     

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112. defmodule Daze.Action do
     defmacro __using__(opts) do
     quote do
     import Plug.Conn
     def init(opts), do: opts
     end
     end
     end
     

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113. defmodule Daze.Actions.Posts.Index do
     use Daze.Action
     alias Daze.Views.Posts
     def call(conn, _opts) do
     posts = Daze.Repo.all()
     conn
     |> put_resp_content_type("text/html")
     |> send_resp(200, Posts.index(posts: posts))
     end
     end
     

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114. defmodule Daze.Actions.Posts.Index do
     use Daze.Action
     alias Daze.Views.Posts
     def call(conn, _opts) do
     posts = Daze.Repo.all()
     conn
     |> put_resp_content_type("text/html")
     |> send_resp(200, Posts.index(posts: posts))
     end
     end
     

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115. defmodule Daze.Actions.Posts.Index do
     use Daze.Action
     alias Daze.Views.Posts
     def call(conn, _opts) do
     posts = Daze.Repo.all()
     render(conn, Posts.index(posts: posts))
     end
     def render(conn, body) do
     conn
     |> put_resp_content_type("text/html")
     |> send_resp(200, body)
     end
     end
     

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116. defmodule Daze.Action do
     defmacro __using__(opts) do
     quote do
     import Plug.Conn
     def init(opts), do: opts
     end
     end
     end
     

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117. defmodule Daze.Action do
     defmacro __using__(opts) do
     quote do
     import Plug.Conn
     import Daze.Action.Helpers
     def init(opts), do: opts
     end
     end
     end
     

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118. defmodule Daze.Action do
     defmacro __using__(opts) do
     quote do
     import Plug.Conn
     import Daze.Action.Helpers
     def init(opts), do: opts
     end
     end
     defmodule Helpers do
     end
     end
     

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119. defmodule Daze.Action do
     defmacro __using__(opts) do
     quote do
     import Plug.Conn
     import Daze.Action.Helpers
     def init(opts), do: opts
     end
     end
     defmodule Helpers do
     import Plug.Conn
     def render(conn, body) do
     conn
     |> put_resp_content_type("text/html")
     |> send_resp(200, body)
     end
     end
     end
     

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120. defmodule Daze.Actions.Posts.Index do
     use Daze.Action
     alias Daze.Views.Posts
     def call(conn, _opts) do
     posts = Daze.Repo.all()
     render(conn, Posts.index(posts: posts))
     end
     end
     

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121. defmodule Daze.Actions.Posts.Create do
     use Daze.Action
     def call(conn, _opts) do
     %{ "post" => post, "author" => author } = conn.params
     Daze.Repo.insert(author, %{body: post, author: author})
     url = "/"
     conn
     |> put_resp_header("location", url)
     |> put_resp_content_type("text/html")
     |> send_resp(302, "You are being redirected to #{url}")
     end
     end
     

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122. defmodule Daze.Actions.Posts.Create do
     use Daze.Action
     def call(conn, _opts) do
     %{ "post" => post, "author" => author } = conn.params
     Daze.Repo.insert(author, %{body: post, author: author})
     url = "/"
     conn
     |> put_resp_header("location", url)
     |> put_resp_content_type("text/html")
     |> send_resp(302, "You are being redirected to #{url}")
     end
     end
     

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123. defmodule Daze.Actions.Posts.Create do
     use Daze.Action
     def call(conn, _opts) do
     %{ "post" => post, "author" => author } = conn.params
     Daze.Repo.insert(author, %{body: post, author: author})
     redirect(conn, to: "/")
     end
     def redirect(conn, to: url) do
     conn
     |> put_resp_header("location", url)
     |> put_resp_content_type("text/html")
     |> send_resp(302, "You are being redirected to #{url}")
     end
     end
     

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124. defmodule Daze.Action do
     defmacro __using__(opts) do
     quote do
     import Plug.Conn
     import Daze.Action.Helpers
     def init(opts), do: opts
     end
     end
     defmodule Helpers do
     import Plug.Conn
     def render(conn, body) do
     conn
     |> put_resp_content_type("text/html")
     |> send_resp(200, body)
     end
     end
     end
     

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125. defmodule Daze.Action do
     defmacro __using__(opts) do
     quote do
     import Plug.Conn
     import Daze.Action.Helpers
     def init(opts), do: opts
     end
     end
     defmodule Helpers do
     import Plug.Conn
     def render(conn, body) do
     # snip
     end
     def redirect(conn, to: url) do
     conn
     |> put_resp_header("location", url)
     |> put_resp_content_type("text/html")
     |> send_resp(302, "You are being redirected to #{url}")
     end
     end
     end
     

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126. defmodule Daze.Action do
     defmacro __using__(opts) do
     quote do
     import Plug.Conn
     import Daze.Action.Helpers
     def init(opts), do: opts
     end
     end
     defmodule Helpers do
     import Plug.Conn
     def render(conn, body) do
     # snip
     end
     def redirect(conn, to: url) do
     conn
     |> put_resp_header("location", url)
     |> put_resp_content_type("text/html")
     |> send_resp(302, "You are being redirected to #{url}")
     end
     end
     end
     

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127. defmodule Daze.Actions.Posts.Create do
     use Daze.Action
     def call(conn, _opts) do
     %{ "post" => post, "author" => author } = conn.params
     Daze.Repo.insert(author, %{body: post, author: author})
     redirect(conn, to: "/")
     end
     end
     

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128. Daze.View
     

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129. defmodule Daze.Views.Posts do
     require EEx
     EEx.function_from_file
     :def,
     :index,
     "lib/daze/templates/posts/index.html.eex",
     [:assigns]
     end
     

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130. defmodule Daze.Views.Posts do
     require EEx
     EEx.function_from_file
     :def,
     :index,
     "lib/daze/templates/posts/index.html.eex",
     [:assigns]
     end
     

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131. config/
     deps/
     lib/
     daze/
     + view.ex
     test/
     mix.exs
     mix.lock
     

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132. defmodule Daze.View do
     @root_path "lib/daze/templates"
     end
     

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133. defmodule Daze.View do
     @root_path "lib/daze/templates"
     defmacro deftemplate(template_name, function_name) do
     end
     end
     

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134. defmodule Daze.View do
     @root_path "lib/daze/templates"
     defmacro deftemplate(template_name, function_name) do
     template_path = Path.join(@root_path, template_name)
     end
     end
     

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135. defmodule Daze.View do
     @root_path "lib/daze/templates"
     defmacro deftemplate(template_name, function_name) do
     template_path = Path.join(@root_path, template_name)
     quote do
     require EEx
     EEx.function_from_file(
     :def
     )
     end
     end
     end
     

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136. defmodule Daze.View do
     @root_path "lib/daze/templates"
     defmacro deftemplate(template_name, function_name) do
     template_path = Path.join(@root_path, template_name)
     quote do
     require EEx
     EEx.function_from_file(
     :def,
     unquote(function_name),
     unquote(template_path)
     )
     end
     end
     end
     

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137. defmodule Daze.View do
     @root_path "lib/daze/templates"
     defmacro deftemplate(template_name, function_name) do
     template_path = Path.join(@root_path, template_name)
     quote do
     require EEx
     EEx.function_from_file(
     :def,
     unquote(function_name),
     unquote(template_path),
     [:assigns]
     )
     end
     end
     end
     

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138. defmodule Daze.View do
     defmacro __using__(_) do
     quote do
     import Daze.View
     end
     end
     @root_path "lib/daze/templates"
     defmacro deftemplate(template_name, function_name) do
     template_path = Path.join(@root_path, template_name)
     quote do
     require EEx
     EEx.function_from_file(
     :def,
     unquote(function_name),
     unquote(template_path),
     [:assigns]
     )
     end
     end
     end
     

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139. defmodule Daze.Views.Posts do
     use Daze.View
     deftemplate("posts/index.html.eex", :index)
     end
     

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140. View Slide

141. Sessions
     

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142. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :dispatch
     # snip
     end
     

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143. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug Plug.Session,
     plug :dispatch
     # snip
     end
     

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144. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug Plug.Session, store: :cookie,
     plug :dispatch
     # snip
     end
     

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145. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug Plug.Session, store: :cookie, key: "_daze_app",
     plug :dispatch
     # snip
     end
     

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146. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug Plug.Session, store: :cookie, key: "_daze_app", signing_salt: "daze salt"
     plug :dispatch
     # snip
     end
     

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147. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :put_secret_key_base
     plug Plug.Session, store: :cookie, key: "_daze_app", signing_salt: "daze salt"
     plug :dispatch
     # snip
     def put_secret_key_base(conn, _) do
     end
     end
     

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148. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :put_secret_key_base
     plug Plug.Session, store: :cookie, key: "_daze_app", signing_salt: "daze salt"
     plug :dispatch
     # snip
     def put_secret_key_base(conn, _) do
     put_in(
     conn.secret_key_base,
     "tosp2eJ0EVDXq/litnqe3iTMf4oGJuos0PbJk1NzkL4SaMEPB8OGu4T8Ym+WavGY"
     )
     end
     end
     

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149. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :put_secret_key_base
     plug Plug.Session, store: :cookie, key: "_daze_app", signing_salt: "daze salt"
     plug :fetch_session
     plug :dispatch
     # snip
     end
     

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150. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :put_secret_key_base
     plug Plug.Session, store: :cookie, key: "_daze_app", signing_salt: "daze salt"
     plug :fetch_session
     plug :dispatch
     get "/", to: Daze.Actions.Posts.Index
     post "/posts", to: Daze.Actions.Posts.Create
     get "/sign_in", to: Daze.Actions.Sessions.New
     # snip
     end
     

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151. config/
     deps/
     lib/
     daze/
     actions/
     sessions/
     + new.ex
     test/
     mix.exs
     mix.lock
     

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152. defmodule Daze.Actions.Sessions.New do
     use Daze.Action
     end
     

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153. defmodule Daze.Actions.Sessions.New do
     use Daze.Action
     def call(conn, _opts) do
     render(conn, Daze.Views.Sessions.new([]))
     end
     end
     

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154. config/
     deps/
     lib/
     daze/
     views/
     + sessions.ex
     test/
     mix.exs
     mix.lock
     

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155. defmodule Daze.Views.Sessions do
     use Daze.View
     deftemplate("sessions/new.html.eex", :new)
     end
     

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156. config/
     deps/
     lib/
     daze/
     templates/
     sessions/
     + new.html.eex
     test/
     mix.exs
     mix.lock
     

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157. 
     
     
     
     
     Sign in
     
     
     Email:
     
     Password:
     
     Sign in
     
     
     
     
     

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158. 
     
     
     
     
     Sign in
     
     
     Email:
     
     Password:
     
     Sign in
     
     
     
     
     

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159. View Slide

160. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :put_secret_key_base
     plug Plug.Session, store: :cookie, key: "daze_app", signing_salt: "daze salt"
     plug :fetch_session
     plug :dispatch
     get "/", to: Daze.Actions.Posts.Index
     post "/posts", to: Daze.Actions.Posts.Create
     get "/sign_in", to: Daze.Actions.Sessions.New
     post "/sessions", to: Daze.Actions.Sessions.Create
     # snip
     end
     

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161. config/
     deps/
     lib/
     daze/
     actions/
     sessions/
     + create.ex
     test/
     mix.exs
     mix.lock
     

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162. defmodule Daze.Actions.Sessions.Create do
     use Daze.Action
     end
     

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163. defmodule Daze.Actions.Sessions.Create do
     use Daze.Action
     def call(conn, _opts) do
     %{"email" => email} = conn.params
     conn
     |> put_session(:current_user_email, email)
     |> redirect(to: "/")
     end
     end
     

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164. defmodule Daze.Actions.Sessions.Create do
     use Daze.Action
     def call(conn, _opts) do
     %{"email" => email} = conn.params
     conn
     |> put_session(:current_user_email, email)
     |> redirect(to: "/")
     end
     end
     

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165. defmodule Daze.Actions.Posts.Index do
     use Daze.Action
     alias Daze.Views.Posts
     def call(conn, _opts) do
     posts = Daze.Repo.all()
     conn
     |> render(Posts.index(posts: posts))
     end
     end
     

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166. defmodule Daze.Actions.Posts.Index do
     use Daze.Action
     alias Daze.Views.Posts
     def call(conn, _opts) do
     posts = Daze.Repo.all()
     current_user_email = get_session(conn, :current_user_email)
     conn
     |> render(Posts.index(posts: posts))
     end
     end
     

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167. defmodule Daze.Actions.Posts.Index do
     use Daze.Action
     alias Daze.Views.Posts
     def call(conn, _opts) do
     posts = Daze.Repo.all()
     current_user_email = get_session(conn, :current_user_email)
     conn
     |> render(Posts.index(posts: posts, current_user_email: current_user_email))
     end
     end
     

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168. 
     
     
     
     
     Posts
     <%= if @current_user_email do %>
     Welcome <%= @current_user_email %>
     <% else %>
     Sign In
     <% end %>
     # snip
     
     
     
     

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169. View Slide

170. View Slide

171. View Slide

172. Static assets
     

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173. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :put_secret_key_base
     plug Plug.Session, store: :cookie, key: "daze_app", signing_salt: "daze salt"
     plug :fetch_session
     plug :dispatch
     # snip
     end
     

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174. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug Plug.Static,
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :put_secret_key_base
     plug Plug.Session, store: :cookie, key: "daze_app", signing_salt: "daze salt"
     plug :fetch_session
     plug :dispatch
     # snip
     end
     

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175. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug Plug.Static, from: :daze, at: "/",
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :put_secret_key_base
     plug Plug.Session, store: :cookie, key: "daze_app", signing_salt: "daze salt"
     plug :fetch_session
     plug :dispatch
     # snip
     end
     

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176. defmodule Daze.Router do
     use Plug.Router
     # snip
     plug Plug.Logger
     plug Plug.Static, from: :daze, at: "/", only: ["images", "css"]
     plug :match
     plug Plug.Parsers, parsers: [:urlencoded, :multipart]
     plug :put_secret_key_base
     plug Plug.Session, store: :cookie, key: "daze_app", signing_salt: "daze salt"
     plug :fetch_session
     plug :dispatch
     # snip
     end
     

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177. 
     
     
     
     
     # snip
     
     

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178. config/
     deps/
     lib/
     priv/
     static/
     css/
     + app.css
     test/
     mix.exs
     mix.lock
     

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179. body {
     background-color: #fff;
     font-family: 'Open Sans', sans-serif;
     }
     .container {
     display: flex;
     flex-direction: column;
     }
     .header {
     display: flex;
     flex-flow: row nowrap;
     justify-content: space-evenly;
     align-items: center;
     margin: 4em;
     }
     .banner-image {
     width: 100px;
     }
     .main {
     display: flex;
     flex-flow: column nowrap;
     margin: auto;
     }
     .posts {
     margin: 3em 0.5em;
     }
     .post-item {
     margin: 0 0.5em 3em 0.5em;
     list-style: none;
     }
     .post-body {
     font-size: 1.5em;
     }
     .post-author {
     margin-top: 0.3em;
     display: block;
     text-align: right;
     }
     

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180. 
     
     
     
     
     
     
     
     
     Posts
     # snip
     
     
     
     

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181. config/
     deps/
     lib/
     priv/
     static/
     images/
     + elixir-daze.svg
     test/
     mix.exs
     mix.lock
     

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182. Demo
     

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183. View Slide

184. Final thoughts
     

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185. github.com/germsvel/daze
     @germsvel
     

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