Shield

Shield is an OAuth2 Provider hex package and also a standalone microservice build top of the Phoenix Framework and 'authable' package.

Shield can be used inside an application or can be used as standalone microservice. Shield simply plays role of the 'authorization server' on OAuth2 scheme.

Installation

As Package

The package can be installed as:

1. Add shield to your list of dependencies in mix.exs and run mix deps.get:

   def deps do
     [{:shield, "~> 0.6.0"}]
   end

2. Ensure shield is started before your application:

   def application do
     [applications: [:shield]]
   end

3. Add authable configurations to your config/config.exs file:

   config :authable,
     ecto_repos: [Authable.Repo],
     repo: Authable.Repo,
     resource_owner: Authable.Model.User,
     token_store: Authable.Model.Token,
     client: Authable.Model.Client,
     app: Authable.Model.App,
     expires_in: %{
       access_token: 3600,
       refresh_token: 24 * 3600,
       authorization_code: 300,
       session_token: 30 * 24 * 3600
     },
     grant_types: %{
       authorization_code: Authable.GrantType.AuthorizationCode,
       client_credentials: Authable.GrantType.ClientCredentials,
       password: Authable.GrantType.Password,
       refresh_token: Authable.GrantType.RefreshToken
     },
     auth_strategies: %{
       headers: %{
         "authorization" => [
           {~r/Basic ([a-zA-Z\-_\+=]+)/, Authable.Authentication.Basic},
           {~r/Bearer ([a-zA-Z\-_\+=]+)/, Authable.Authentication.Bearer},
         ],
         "x-api-token" => [
           {~r/([a-zA-Z\-_\+=]+)/, Authable.Authentication.Bearer}
         ]
       },
       query_params: %{
         "access_token" => Authable.Authentication.Bearer
       },
       sessions: %{
         "session_token" => Authable.Authentication.Session
       }
     },
     scopes: ~w(read write session),
     renderer: Authable.Renderer.RestApi

4. Add shield notifier configurations to your config/config.exs file:

   config :shield_notifier,
     channels: %{
       email: %{
         from: %{
           name: {:system, "APP_NAME", "Shield Notifier"},
           email: {:system, "APP_FROM_EMAIL", "no-reply@localhost"}
         }
       }
     }

5. Add your favorite mail sender Bamboo adapter configuration to your config/prod.exs file:

   config :shield_notifier, Shield.Notifier.Mailer,
     adapter: Bamboo.SendgridAdapter,
     api_key: System.get_env("SENDGRID_API_KEY")

6. Add shield configurations to your config/config.exs file:

   config :shield,
     confirmable: true,
     otp_check: false,
     hooks: Shield.Hook.Default,
     views: %{
       changeset: Shield.ChangesetView,
       error: Shield.ErrorView,
       app: Shield.AppView,
       client: Shield.ClientView,
       token: Shield.TokenView,
       user: Shield.UserView
     },
     cors_origins: "http://localhost:4200, *",
     front_end: %{
       base: "http://localhost:4200",
       confirmation_path: "/users/confirm?confirmation_token={{confirmation_token}}",
       reset_password_path: "/users/reset-password?reset_token={{reset_token}}"
     }

   If you want to disable a authorization strategy, then delete it from shield configuration.

   If you want to add a new authorization strategy then add your own module.

7. Use installer to generate controllers, views, models and migrations from originals

   # Run only if you need to change behaviours, otherwise skip this.
   mix shield.install

8. Add database configurations for the Authable.Repo on env config files:

   config :authable, Authable.Repo,
     adapter: Ecto.Adapters.Postgres,
     username: "postgres",
     password: "",
     database: "",
     hostname: "",
     pool_size: 10

9. Run migrations for Authable.Repo (Note: all id fields are UUID type):

   mix ecto.create
   mix ecto.migrate -r Authable.Repo

10. Add routes

    pipeline :api do
      plug :accepts, ["json"]
    end
    
    scope "/", Shield do
      pipe_through :api
      resources "/clients", ClientController, except: [:new, :edit]
    
      get     "/apps", AppController, :index
      get     "/apps/:id", AppController, :show
      delete  "/apps/:id", AppController, :delete
      post    "/apps/authorize", AppController, :authorize
    
      get     "/tokens/:id", TokenController, :show
      post    "/tokens", TokenController, :create
    
      post    "/users/register", UserController, :register
      post    "/users/login", UserController, :login
      delete  "/users/logout", UserController, :logout
      get     "/users/me", UserController, :me
      get     "/users/confirm", UserController, :confirm
      post    "/users/recover_password", UserController, :recover_password
      post    "/users/reset_password", UserController, :reset_password
      post    "/users/change_password", UserController, :change_password
    
      get     "/settings", SettingController, :index
      put     "/settings/:id", SettingController, :update
      patch   "/settings/:id", SettingController, :update
    end

11. You are ready to go!

Standalone

git clone git@github.com:mustafaturan/shield.git
cd shield
mix deps.get
mix ecto.create -r Authable.Repo
mix ecto.migrate -r Authable.Repo
mix phoenix.server

API Endpoints Documentation

You can use paste the content of swagger.yml to http://editor.swagger.io/ https://raw.githubusercontent.com/mustafaturan/shield/master/swagger.yml.

Heroku

Usage, Examples & Configuration

Protecting resources

Inside your controller modules; add the following lines to restrict access to actions.

# Add plug to restrict access to all actions
plug Authable.Plug.Authenticate, [scopes: ~w(read)]

# Example inside module

defmodule SomeModule.AppController do
  use SomeModule.Web, :controller
  ...
  plug Authable.Plug.Authenticate, [scopes: ~w(read write)]

  def index(conn, _params) do
    # access to current user on successful authentication
    current_user = conn.assigns[:current_user]
    ...
  end

  ...
end

If you need to restrict specific resource, you may guard with when clause. Forexample, to check authentication only on :create, :update and :delete actions of your controllers.

plug Authable.Plug.Authenticate, [scopes: ~w(read write)] when action in [:create, :update, :delete]

Incase you do not want to allow registered user to access resources:

# Add plug `Authable.Plug.UnauthorizedOnly` for necessary actions
plug :Authable.Plug.UnauthorizedOnly when action in [:register]

# Example inside module

defmodule SomeModule.AppController do
  use SomeModule.Web, :controller
  ...

  plug Authable.Plug.Authenticate, [scopes: ~w(read write)] when action in [:create]
  plug Authable.Plug.UnauthorizedOnly when action in [:register]

  def register(conn, _params) do
    # if user logged in, then will response automatically with
    # unprocessable_entity 422 header and error
    ...
  end

  def create(conn, params) do
    # access to current user on successful authentication
    current_user = conn.assigns[:current_user]
    ...
  end

  ...
end

Manually handling authentication:

defmodule SomeModule.AppController do
  use SomeModule.Web, :controller
  ...
  import Authable.Helper

  def register(conn, _params) do
    required_scopes = ~w(session)
    case authorize_for_resource(conn, required_scopes) do
      {:ok, current_user} -> IO.puts(current_user.email)
      {:error, errors, _} -> IO.inspect(errors)
      nil -> IO.puts("not authencated!")
    end
    ...
  end
end

Accessing resource owner info

By default Authable.Model.User represents resource owner. To access resource owner, plug Authable.Plug.Authenticate must be called. Then current user information will be available by conn assignments.

conn.assigns[:current_user]

Allowing only email confirmed user to access resources

To allow only confirmed user to access certain resources, you need to add confirmable plug to your controllers

  plug Shield.Arm.Confirmable, [enabled: Application.get_env(:shield, :confirmable)] when action in [:me, :change_password]

Views

By default REST style views are used to represent error and data models. In shield configuration, it is possible to change view modules to represent non-rest style data models like JSON-API or any other data model.

Hooks

In shield package; by default hooks do nothing, but when you need to implement a callback after or before execution of functions, it might be very useful. All you need to do is create a module that use the hook behaviour module and then update the config.exs.

Sample module implementation:

defmodule Shield.Hook.Sample do
  use Shield.Hook
  ...

  def before_app_authorize(conn, params) do
    # do sth async or sync...
    # All hooks must return `Plug.Conn.t` type.
    conn
  end
  ...
end

Here is supported hooks and return types:

  params is a map type
  http_status_code is an atom type
  res is an any type
  conn is a Plug.Conn.t type

  def before_app_authorize(conn, _params)
  def before_app_delete(conn, _params)
  def after_app_authorize_failure(conn, {_params, {_http_status_code, _res}})
  def after_app_authorize_success(conn, {_params, _res})
  def after_app_delete(conn, _params)
  def before_client_create(conn, _params)
  def before_client_update(conn, _params)
  def before_client_delete(conn, _params)
  def after_client_create_success(conn, {_params, _res})
  def after_client_create_failure(conn, {_params, {_http_status_code, _res}})
  def after_client_update_failure(conn, {_params, {_http_status_code, _res}})
  def after_client_update_success(conn, {_params, _res})
  def after_client_delete(conn, _params)
  def before_token_create(conn, _params)
  def after_token_create_failure(conn, {_params, {_http_status_code, _res}})
  def after_token_create_success(conn, {_params, _res})
  def before_user_register(conn, _params)
  def before_user_login(conn, _params)
  def after_user_change_password_failure(conn, {_params, {_http_status_code, _res}})
  def after_user_change_password_success(conn, {_params, _res})
  def after_user_confirm_failure(conn, {_params, {_http_status_code, _res}})
  def after_user_confirm_success(conn, {_params, _res})
  def after_user_login_failure(conn, {_params, {_http_status_code, _res}})
  def after_user_login_success(conn, {_params, _res})
  def after_user_recover_password_failure(conn, {_params, {_http_status_code, _res}})
  def after_user_recover_password_success(conn, {_params, _res})
  def after_user_register_failure(conn, {_params, {_http_status_code, _res}})
  def after_user_register_success(conn, {_params, _res})
  def after_user_reset_password_failure(conn, {_params, {_http_status_code, _res}})
  def after_user_reset_password_success(conn, {_params, _res})

Client Implementations

Since 'shield' application is a microservice. Several client applications might be written using shield. Please do not hesitate to raise an issue with your implementation, description and demo url.

Notes

API may change up to v1.0

Contributing

Issues, Bugs, Documentation, Enhancements

1. Fork the project

2. Make your improvements and write your tests.

3. Document what you did/change.

4. Make a pull request.

To add new strategy

Shield and Authable are extensible modules, you can create your strategy and share as hex package(Which can be listed on Wiki pages).

Todo

• Swagger documentation

• Sample UI Client: https://github.com/mustafaturan/shield/tree/ui

• Sample resource server implementation https://github.com/mustafaturan/shield-blog-sample

• Optional one time password protection

• Background job to delete expired tokens

• Optional captcha protection

References

https://tools.ietf.org/html/rfc6749

https://github.com/mustafaturan/authable

https://hexdocs.pm/authable