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 :

```elixir
def deps do
  [{:shield, "~> 0.3.3"}]
end
```

2. Ensure shield is started before your application:

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

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

```elixir
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:

```elixir
config :shield_notifier,
  channels: %{
    email: %{
      from: {
        System.get_env("APP_NAME") || "Shield Notifier",
        System.get_env("APP_FROM_EMAIL") || "no-reply@localhost"}
    }
  }
```

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

```elixir
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:

```elixir
config :shield,
  confirmable: true,
  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.

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

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

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

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

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

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

8. Add routes

```elixir
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
end
```

9. You are ready to go!

Standalone

git clone [email protected]:mustafaturan/shield.git
cd shields
mix deps.get
mix ecto.create -r Authable.Repo
mix ecto.migrate -r Authable.Repo
mix phoenix.server

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.

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

• New protection arms like recaptcha and one time password protections

• EmberJS client implementation as a seperate sample app: https://github.com/mustafaturan/shield/tree/ui

• Swagger documentation

• Background job to delete expired tokens

• Sample resource server implementation

References

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

https://github.com/mustafaturan/authable

https://hexdocs.pm/authable