# `Oidcc.Plug.AuthorizationCallback`
[🔗](https://github.com/erlef/oidcc_plug/blob/989b809174070ef71c9dc545de149854f86d8f7c
/lib/oidcc/plug/authorization_callback.ex#L1)

Retrieve Token for Code Flow Authorization Callback

This plug does not send a response. Instead it will load and validate all
token data and leave the rest to a controller action that will be executed
after.

## Via `Phoenix.Router`

```elixir
defmodule SampleAppWeb.Router do
  use Phoenix.Router

  # ...

  pipeline :oidcc_callback do
    plug Oidcc.Plug.AuthorizationCallback,
      provider: SampleApp.GoogleOpenIdConfigurationProvider,
      client_id: Application.compile_env!(:sample_app, [Oidcc.Plug.Authorize, :client_id]),
      client_secret: Application.compile_env!(:sample_app, [Oidcc.Plug.Authorize, :client_secret]),
      redirect_uri: "https://localhost:4000/oidcc/callback"
  end

  forward "/oidcc/authorize", to: Oidcc.Plug.Authorize,
    init_opts: [...]

  scope "/oidcc/callback", SampleAppWeb do
    pipe_through :oidcc_callback

    get "/", AuthController, :handle_callback
    post "/", AuthController, :handle_callback
  end
end
```

## Via `Controller`

```elixir
defmodule SampleAppWeb.AuthController do
  # ...

  plug Oidcc.Plug.AuthorizationCallback,
    provider: SampleApp.GoogleOpenIdConfigurationProvider,
    client_id: Application.compile_env!(:sample_app, [Oidcc.Plug.Authorize, :client_id]),
    client_secret: Application.compile_env!(:sample_app, [Oidcc.Plug.Authorize, :client_secret]),
    redirect_uri: "https://localhost:4000/oidcc/callback"
    when action in [:handle_callback]

  def handle_callback(
    %Plug.Conn{private: %{
      Oidcc.Plug.AuthorizationCallback => {:ok, {token, userinfo}}
      Oidcc.Plug.Authorize.State => "query_param_state" | nil
    }},
    _params
  ) do
    # Handle Success

    conn
    |> put_session("auth_token", token)
    |> put_session("auth_userinfo", userinfo)
    |> redirect(to: "/")
  end

  def handle_callback(
    %Plug.Conn{private: %{
      Oidcc.Plug.AuthorizationCallback => {:error, reason}}
    },
    _params
  ) do
    # Handle Error

    conn
    |> put_status(400)
    |> render("error.html", reason: reason)
  end
end
```

# `error`
*since 0.1.0* 

```elixir
@type error() ::
  :oidcc_client_context.error()
  | :oidcc_token.error()
  | :oidcc_userinfo.error()
  | :useragent_mismatch
  | :peer_ip_mismatch
  | {:missing_request_param, param :: String.t()}
```

# `opts`
*since 0.1.0* 

```elixir
@type opts() :: [
  provider: GenServer.name() | nil,
  client_store: module() | nil,
  client_id: String.t() | (-> String.t()) | (Plug.Conn.t() -> String.t()) | nil,
  client_secret:
    String.t() | (-> String.t()) | (Plug.Conn.t() -> String.t()) | nil,
  client_context_opts:
    :oidcc_client_context.opts() | (-> :oidcc_client_context.opts()),
  client_profile_opts: :oidcc_profile.opts(),
  redirect_uri: String.t() | (-> String.t()) | (Plug.Conn.t() -> String.t()),
  check_useragent: boolean(),
  check_peer_ip: boolean(),
  retrieve_userinfo: boolean(),
  request_opts: :oidcc_http_util.request_opts()
]
```

Plug Configuration Options

## Options

* `provider` - name of the `Oidcc.ProviderConfiguration.Worker`
* `client_id` - OAuth Client ID to use for the introspection
* `client_secret` - OAuth Client Secret to use for the introspection
* `client_context_opts` - Options for Client Context Initialization
* `client_profile_opts` - Options for Client Context Profiles
* `redirect_uri` - Where to redirect for callback
* `check_useragent` - check if useragent is the same as before the
  authorization request
* `check_peer_ip` - check if the client IP is the same as before the
  authorization request
* `retrieve_userinfo` - whether to load userinfo from the provider
* `request_opts` - request opts for http calls to provider
* `client_store` - A module name that implements the `Oidcc.Plug.ClientStore` behaviour
to fetch the client context from a store instead of using the `provider`, `client_id` and `client_secret`
directly. This is useful for storing the client context in a database or other persistent
storage.

---

*Consult [api-reference.md](api-reference.md) for complete listing*