Elixir | Phoenix context logic (with and without auth)

odyright · September 3, 2017, 4:34pm

I followed the complete tutorial explaining how to handle context & authentication/authorization by @chrismccord …and I took advantage of his post about decoupling auth from dockyard blog auth for phoenix context and from Adding CMS functions in phoenix context

According to this, In my case( CMS is ENR ) all created students need an enroller, the enroller is linked to a user(authenticated) with its own session (that’s great): Student ->belongs_to Enroller, Enroller ->belongs_to User, users have their own credentials.

the resources "/admissions", AdmissionController is protected that’s fine.

But Now I want to expose some fact: what about if we want to allow student registering himself/herself? how the code will look like?

for self-enrollment or self-registration instead of doing it by the admin’s folk… it’ll be good.

here is what I did but I’m always redirect to the authentication page, the result: ***“you have to be logged in”***.

when the Admin is logged in/registered… S/he can achieve administrative tasks (create: Students, Enrollers, pages, etc.) that’s allowed by:
```
scope "/enr", HelloWeb.ENR, as: :enr do

  pipe_through [:browser, :authenticate_user]
  resources "/admissions", AdmissionController
end
```

for the admission’s tasks

In the mentioned case earlier if we consider that scope CMS or (ENR) is the admin part and we want to allow students to register themselves through public part I did route like that:

    scope "/", InsWeb do
        pipe_through :browser # Use the default browser stack

        get "/", PageController, :index
        resources "/users", UserController
        resources "/sessions", SessionController, only: [:new, :create, :delete],
                                              singleton: true
        resources "/admissions", AdmissionController, only: [:new, :create, :show]
      end

      scope "/ENR", InsWeb.ENR, as: :enr do
        pipe_through [:browser, :authenticate_user]

        resources "/admissions", AdmissionController
      end

      defp authenticate_user(conn, _) do
        case get_session(conn, :user_id) do
          nil ->
            conn
            |> Phoenix.Controller.put_flash(:error, "Login required")
            |> Phoenix.Controller.redirect(to: "/")
            |> halt()
          user_id ->
            assign(conn, :current_user, Ins.Accounts.get_user!(user_id))
        end
      end

all seems good I reached the admission page through public part but when I submitted the form ==== nothing…I always got “Login required”
so it’s not possible to allow student self-registration…

the AdmissionController.ex in the CMS(ENRin my case) scope looks like:

   defmodule InsWeb.ENR.AdmissionController do
     use InsWeb, :controller

     plug :require_existing_enroller
     plug :authorize_admission when action in [:edit, :update, :delete]

     alias Ins.ENR
     alias Ins.ENR.Admission

     def index(conn, _params) do
       admissions = ENR.list_admissions()
       render(conn, "index.html", admissions: admissions)
     end

     def new(conn, _params) do
       changeset = ENR.change_admission(%Admission{})
       render(conn, "new.html", changeset: changeset)
     end

     def create(conn, %{"admission" => admission_params}) do
       case ENR.create_admission(conn.assigns.current_enroller, admission_params) do
         {:ok, admission} ->
           conn
           |> put_flash(:info, "Admission created successfully.")
           |> redirect(to: enr_admission_path(conn, :show, admission))
         {:error, %Ecto.Changeset{} = changeset} ->
           render(conn, "new.html", changeset: changeset)
       end
     end

     def show(conn, %{"id" => id}) do
       admission = 
         id
         |> ENR.get_admission!()
         |> ENR.inc_admission_views()

       render(conn, "show.html", admission: admission)
     end

     def edit(conn, %{"id" => id}) do
       admission = ENR.get_admission!(id)
       changeset = ENR.change_admission(admission)
       render(conn, "edit.html", admission: admission, changeset: changeset)
     end

     def update(conn, %{"id" => id, "admission" => admission_params}) do
       admission = ENR.get_admission!(id)

       case ENR.update_admission(conn.assigns.admission, admission_params) do
         {:ok, admission} ->
           conn
           |> put_flash(:info, "Admission updated successfully.")
           |> redirect(to: enr_admission_path(conn, :show, admission))
         {:error, %Ecto.Changeset{} = changeset} ->
           render(conn, "edit.html", admission: admission, changeset: changeset)
       end
     end

     def delete(conn, %{"id" => id}) do
       admission = ENR.get_admission!(id)
       {:ok, _admission} = ENR.delete_admission(conn.assigns.admission)

       conn
       |> put_flash(:info, "Admission deleted successfully.")
       |> redirect(to: enr_admission_path(conn, :index))
     end

     defp require_existing_enroller(conn, _) do
       enroller = ENR.ensure_enroller_exists(conn.assigns.current_user)
       assign(conn, :current_enroller, enroller)
     end

     defp authorize_admission(conn, _) do
       admission = ENR.get_admission!(conn.params["id"])

       if conn.assigns.current_enroller.id == admission.enroller_id do
         assign(conn, :admission, admission)
       else
         conn
         |> put_flash(:error, "You can't modify that admission page")
         |> redirect(to: enr_admission_path(conn, :index))
         |> halt()
       end
     end

   end

And the other one out of CMS

      defmodule InsWeb.AdmissionController do
        use InsWeb, :controller

        alias Ins.ENR
        alias Ins.ENR.Admission

        def new(conn, _params) do
          changeset = ENR.change_admission(%Admission{})
          render(conn, "new.html", changeset: changeset)
        end

        def create(conn, %{"admission" => admission_params}) do
          case ENR.create_admission(conn.assigns.current_enroller, admission_params) do
            {:ok, admission} ->
              conn
              |> put_flash(:info, "Admission created successfully.")
              |> redirect(to: enr_admission_path(conn, :show, admission))
            {:error, %Ecto.Changeset{} = changeset} ->
              render(conn, "new.html", changeset: changeset)
          end
        end

        def show(conn, %{"id" => id}) do
          admission = 
            id
            |> ENR.get_admission!()

          render(conn, "show.html", admission: admission)
        end

      end

Any help would be appreciated! thank you!

Here are the other contents

/templates/enr/admission/form.html.eex

<%= form_for @changeset, @action, fn f -> %>
  <%= if @changeset.action do %>
    <div class="alert alert-danger">
      <p>Oops, something went wrong! Please check the errors below.</p>
    </div>
  <% end %>

  <div class="form-group">
    <%= label f, :first_name, class: "control-label" %>
    <%= text_input f, :first_name, class: "form-control" %>
    <%= error_tag f, :first_name %>
  </div>

  <div class="form-group">
    <%= label f, :last_name, class: "control-label" %>
    <%= text_input f, :last_name, class: "form-control" %>
    <%= error_tag f, :last_name %>
  </div>

  <div class="form-group">
    <%= label f, :views, class: "control-label" %>
    <%= number_input f, :views, class: "form-control" %>
    <%= error_tag f, :views %>
  </div>

  <div class="form-group">
    <%= submit "Submit", class: "btn btn-primary" %>
  </div>
<% end %>

/templates/enr/admission/new.html.eex

<h2>New Admission</h2>

<%= render "form.html", Map.put(assigns, :action, enr_admission_path(@conn, :create)) %>

<span><%= link "Back", to: enr_admission_path(@conn, :index) %></span>