# Shield [](https://beta.hexfaktor.org/github/mustafaturan/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`:
def deps do
[{:shield, "~> 0.1.0"}]
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.Models.User,
token_store: Authable.Models.Token,
client: Authable.Models.Client,
app: Authable.Models.App,
expires_in: %{
access_token: 3600,
refresh_token: 24 * 3600,
authorization_code: 300,
session_token: 30 * 24 * 3600
},
strategies: %{
authorization_code: Authable.AuthorizationCodeGrantType,
client_credentials: Authable.ClientCredentialsGrantType,
password: Authable.PasswordGrantType,
refresh_token: Authable.RefreshTokenGrantType
},
scopes: ~w(read write session)
4. Add shield configurations to your `config/config.exs` file:
config :shield,
authorizations: %{
headers: %{
"authorization" => %{
"Basic" => Authable.Authentications.Basic,
"Bearer" => Authable.Authentications.Bearer
},
"x-api-token" => Authable.Authentications.Bearer
},
query_params: %{
"access_token" => Authable.Authentications.Bearer
},
session: %{
"session_token" => Authable.Authentications.Session
}
},
views: %{
changeset: Shield.ChangesetView,
error: Shield.ErrorView,
app: Shield.AppView,
client: Shield.ClientView,
token: Shield.TokenView,
user: Shield.UserView
},
cors_origins: ["localhost:4000", "*"]
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. 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
6. Run migrations for Authable.Repo (Note: all id fields are UUID type):
mix ecto.create
mix ecto.migrate -r Authable.Repo
7. Use installer to generate controllers from originals
# Run only if you need to change controller behaviours, otherwise skip this.
mix shield.install
8. 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
end
9. You are ready to go!
### Standalone
git clone git@github.com:mustafaturan/shield.git
cd shields
mix deps.get
mix ecto.create
mix ecto.migrate -r Authable.Repo
mix phoenix.server
### Heroku
[](https://heroku.com/deploy)
## Usage, Examples & Configuration
### Protecting resources
Inside your controller modules; add the following lines to restrict access to actions.
use Shield.Authorization
# Then add plug to restrict access to all actions
plug :authenticate!
# Example inside module
defmodule SomeModule.AppController do
use SomeModule.Web, :controller
...
use Shield.Authorization
plug :authenticate!
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 :authenticate! when action in [:create, :update, :delete]
Incase you do not want to allow registered user to access resources:
use Shield.Authorization
# Then add plug `:already_logged_in?` function for necessary actions
plug :already_logged_in? when action in [:register]
# Example inside module
defmodule SomeModule.AppController do
use SomeModule.Web, :controller
...
use Shield.Authorization
plug :authenticate! when action in [:create]
plug :already_logged_in? 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
...
use Shield.Authorization
def register(conn, _params) do
current_user = authenticate(conn)
if is_nil(current_user) do
IO.puts "not authencated!"
else
IO.puts current_user.email
end
...
end
end
### Accessing resource owner info
By default `Authable.Models.User` represents resource owner. To access resource owner, plug `authenticate!` or `already_signed_in?` must be called. Then current user information will be available by conn assignments.
conn.assigns[:current_user]
### 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.
## 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
Background job to delete expired tokens
EmberJS client implementation as a seperate sample app
Sample resource server implementation
## References
https://tools.ietf.org/html/rfc6749
https://github.com/mustafaturan/authable
https://hexdocs.pm/authable