The no-brainer library to use for adding OAuth 2.0 provider capabilities to your Elixir app. You can use phoenix_oauth2_provider for easy integration with your Phoenix app.
Add ExOauth2Provider to your list of dependencies in mix.exs:
def deps do [ # ... {:ex_oauth2_provider, "~> 0.5.7"} # ... ] endRun mix deps.get to install it.
Generate the migrations and schema modules:
mix ex_oauth2_provider.installAdd the following to config/config.exs:
config :my_app, ExOauth2Provider, repo: MyApp.Repo, resource_owner: MyApp.Users.UserIf you don't have any user setup, you shuld consider setting up Pow first.
You have to ensure that a resource_owner has been authenticated on the following endpoints, and pass the struct as the first argument in the following methods.
# GET /oauth/authorize?response_type=code&client_id=CLIENT_ID&redirect_uri=CALLBACK_URL&scope=read case ExOauth2Provider.Authorization.preauthorize(resource_owner, params, otp_app: :my_app) do {:ok, client, scopes} -> # render authorization page {:redirect, redirect_uri} -> # redirect to external redirect_uri {:native_redirect, %{code: code}} -> # redirect to local :show endpoint {:error, error, http_status} -> # render error page end # POST /oauth/authorize?response_type=code&client_id=CLIENT_ID&redirect_uri=CALLBACK_URL&scope=read ExOauth2Provider.Authorization.authorize(resource_owner, params, otp_app: :my_app) do {:redirect, redirect_uri} -> # redirect to external redirect_uri {:native_redirect, %{code: code}} -> # redirect to local :show endpoint {:error, error, http_status} -> # render error page end # DELETE /oauth/authorize?response_type=code&client_id=CLIENT_ID&redirect_uri=CALLBACK_URL&scope=read ExOauth2Provider.Authorization.deny(resource_owner, params, otp_app: :my_app) do {:redirect, redirect_uri} -> # redirect to external redirect_uri {:error, error, http_status} -> # render error page end# POST /oauth/token?client_id=CLIENT_ID&client_secret=CLIENT_SECRET&grant_type=authorization_code&code=AUTHORIZATION_CODE&redirect_uri=CALLBACK_URL case ExOauth2Provider.Token.grant(params, otp_app: :my_app) do {:ok, access_token} -> # JSON response {:error, error, http_status} -> # JSON response end # GET /oauth/revoke?client_id=CLIENT_ID&client_secret=CLIENT_SECRET&token=ACCESS_TOKEN case ExOauth2Provider.Token.revoke(params, otp_app: :my_app) do {:ok, %{}} -> # JSON response {:error, error, http_status} -> # JSON response end Revocation will return {:ok, %{}} status even if the token is invalid.
ExOauth2Provider doesn't support implicit grant flow. Instead you should set up an application with no client secret, and use the Authorize code grant flow. client_secret isn't required unless it has been set for the application.
# POST /oauth/token?client_id=CLIENT_ID&client_secret=CLIENT_SECRET&grant_type=client_credentials case ExOauth2Provider.Token.grant(params, otp_app: :my_app) do {:ok, access_token} -> # JSON response {:error, error, http_status} -> # JSON response end Refresh tokens can be enabled in the configuration:
config :my_app, ExOauth2Provider, repo: MyApp.Repo, resource_owner: MyApp.Users.User, use_refresh_token: trueThe refresh_token grant flow will then be enabled.
# POST /oauth/token?client_id=CLIENT_ID&client_secret=CLIENT_SECRET&grant_type=refresh_token&refresh_token=REFRESH_TOKEN case ExOauth2Provider.Token.grant(params, otp_app: :my_app) do {:ok, access_token} -> # JSON response {:error, error, http_status} -> # JSON response end You'll need to provide an authorization method that accepts username and password as arguments, and returns {:ok, resource_owner} or {:error, reason}. Here'a an example:
# Configuration in config/config.exs config :my_app, ExOauth2Provider, password_auth: {Auth, :authenticate} # Module example defmodule Auth do def authenticate(username, password, otp_app: :my_app) do User |> Repo.get_by(email: username) |> verify_password(password) end defp verify_password(nil, password) do check_pw("", password) # Prevent timing attack {:error, :no_user_found} end defp verify_password(%{password_hash: password_hash} = user, password) do case check_pw(password_hash, password) do true -> {:ok, user} false -> {:error, :invalid_password} end end endThe password grant flow will then be enabled.
# POST /oauth/token?client_id=CLIENT_ID&grant_type=password&username=USERNAME&password=PASSWORD case ExOauth2Provider.Token.grant(params, otp_app: :my_app) do {:ok, access_token} -> # JSON response {:error, error, http_status} -> # JSON response end Server wide scopes can be defined in the configuration:
config :my_app, ExOauth2Provider, repo: MyApp.Repo, resource_owner: MyApp.Users.User, default_scopes: ~w(public), optional_scopes: ~w(read update)Looks for a token in the Authorization Header. If one is not found, this does nothing. This will always be necessary to run to load access token and resource owner.
Looks for a verified token loaded by VerifyHeader. If one is not found it will call the :unauthenticated method in the :handler module.
You can use a custom :handler as part of a pipeline, or inside a Phoenix controller like so:
defmodule MyAppWeb.MyController do use MyAppWeb, :controller plug ExOauth2Provider.Plug.EnsureAuthenticated, handler: MyAppWeb.MyAuthErrorHandler endThe :handler module always defaults to ExOauth2Provider.Plug.ErrorHandler.
Looks for a previously verified token. If one is found, confirms that all listed scopes are present in the token. If not, the :unauthorized function is called on your :handler.
defmodule MyAppWeb.MyController do use MyAppWeb, :controller plug ExOauth2Provider.Plug.EnsureScopes, handler: MyAppWeb.MyAuthErrorHandler, scopes: ~w(read write) endWhen scopes' sets are specified through a :one_of map, the token is searched for at least one matching scopes set to allow the request. The first set that matches will allow the request. If no set matches, the :unauthorized function is called.
defmodule MyAppWeb.MyController do use MyAppWeb, :controller plug ExOauth2Provider.Plug.EnsureScopes, handler: MyAppWeb.MyAuthErrorHandler, one_of: [~w(admin), ~w(read write)] endIf the Authorization Header was verified, you'll be able to retrieve the current resource owner or access token.
ExOauth2Provider.Plug.current_access_token(conn) # access the token in the `:default` location ExOauth2Provider.Plug.current_access_token(conn, :custom) # access the token in the `:custom` location if set as `:key` option in `plug ExOauth2Provider.Plug.VerifyHeader`ExOauth2Provider.Plug.current_resource_owner(conn) # Access the loaded resource owner in the `:default` location ExOauth2Provider.Plug.current_resource_owner(conn, :custom) # Access the loaded resource owner in the `:secret` location if set as `:key` option in `plug ExOauth2Provider.Plug.VerifyHeader`You can add your own access token generator, as this example shows:
# config/config.exs config :my_app, ExOauth2Provider, access_token_generator: {AccessToken, :new} defmodule AccessToken def new(access_token) do with_signer(%JWT.token{ resource_owner_id: access_token.resource_owner_id, application_id: access_token.application.id, scopes: access_token.scopes, expires_in: access_token.expires_in, created_at: access_token.created_at }, hs256("my_secret")) end endRemember to change the field type for the token column in the oauth_access_tokens table to accepts tokens larger than 255 characters.
You can add extra values to the response body.
# config/config.exs config :my_app, ExOauth2Provider, access_token_response_body_handler: {CustomResponse, :response} defmodule CustomResponse def response(response_body, access_token) do Map.merge(response_body, %{user_id: access_token.resource_owner.id}) end endRemember to change the field type for the token column in the oauth_access_tokens table to accepts tokens larger than 255 characters.
You'll need to create the migration file and schema modules with the argument --binary-id:
mix ex_oauth2_provider.install --binary-idThis library was made thanks to doorkeeper, guardian and authable, that gave the conceptual building blocks.
Thanks to Benjamin Schultzer for helping to refactor the code.
(The MIT License)
Copyright (c) 2017-2019 Dan Schultzer & the Contributors
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