A simple username/password strategy for Überauth.

1. Add :ueberauth_identity to your list of dependencies in mix.exs:

   def deps do
     [
       {:ueberauth_identity, "~> 0.3"}
     ]
   end

2. Add the strategy to your applications:

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

3. Add Identity to your Überauth configuration:

   config :ueberauth, Ueberauth,
     providers: [
       identity: {Ueberauth.Strategy.Identity, [
         callback_methods: ["POST"]
       ]}
     ]

4. Include the Überauth plug in your controller:

   defmodule MyApp.AuthController do
     use MyApp.Web, :controller
     plug Ueberauth
     ...
   end

5. Create the request and callback routes if you haven't already:

   scope "/auth", MyApp do
     pipe_through :browser
   
     get "/:provider", AuthController, :request
     get "/:provider/callback", AuthController, :callback
     post "/identity/callback", AuthController, :identity_callback
   end

6. Your request phase handler should implement a form or similar method to collect the required login information.

7. The controller callback should validate login information using the Ueberauth.Auth struct:

   def identity_callback(%{assigns: %{ueberauth_auth: auth}} = conn, params) do
     case validate_password(auth.credentials) do
       :ok ->
         user = %{id: auth.uid, name: name_from_auth(auth), avatar: auth.info.image}
         conn
         |> put_flash(:info, "Successfully authenticated.")
         |> put_session(:current_user, user)
         |> redirect(to: "/")
       { :error, reason } ->
         conn
         |> put_flash(:error, reason)
         |> redirect(to: "/")
     end
   end

For an example implementation see the Überauth Example application.

Sometimes it's convenient to nest the returned params under a namespace. For example if you're using a "user" form, your params may come back as:

%{ "user" => { "email" => "my@email.com" … }

If you're using a nested set of attributes like this you'll need to let Überauth Identity know about it. To do this set an option in your config:

config :ueberauth, Ueberauth,
  providers: [
    identity: {Ueberauth.Strategy.Identity, [param_nesting: "user"]}
  ]

By default Überauth Identity will be changing empty values from the returned params to nil. If you want to disable that behaviour set the following option in your config:

config :ueberauth, Ueberauth,
  providers: [
    identity: {Ueberauth.Strategy.Identity, [scrub_params: false]}
  ]

Depending on the configured url you can initial the request through:

/auth/identity/callback

Copyright (c) 2015 Daniel Neighman

Released under the MIT License, which can be found in the repository in LICENSE.