Azure OAuth2 strategy

README.md

@@ -14,6 +14,7 @@ Use Google, Github, Twitter, Facebook, or add your custom strategy for authoriza
   * [OAuth 1.0](lib/pow_assent/strategies/oauth.ex)
   * [OAuth 2.0](lib/pow_assent/strategies/oauth2.ex)
 * Includes the following provider strategies:
+  * [Azure AD](lib/pow_assent/strategies/azure_oauth2.ex)
   * [Basecamp](lib/pow_assent/strategies/basecamp.ex)
   * [Discord](lib/pow_assent/strategies/discord.ex)
   * [Facebook](lib/pow_assent/strategies/facebook.ex)

lib/pow_assent/strategies/azure_oauth2.ex

@@ -0,0 +1,98 @@
+defmodule PowAssent.Strategy.AzureOAuth2 do
+  @moduledoc """
+  Azure AD OAuth 2.0 strategy.
+
+  ## Usage
+
+      config :my_app, :pow_assent,
+        providers:
+            [
+              azure: [
+                client_id: "REPLACE_WITH_CLIENT_ID",
+                client_secret: "REPLACE_WITH_CLIENT_SECRET",
+                strategy: PowAssent.Strategy.AzureOAuth2
+              ]
+            ]
+
+  A tenant id can be set to limit scope of users who can get access (defaults
+  to "common"):
+
+      config :my_app, :pow_assent,
+        providers:
+            [
+              azure: [
+                client_id: "REPLACE_WITH_CLIENT_ID",
+                client_secret: "REPLACE_WITH_CLIENT_SECRET",
+                tenant_id: "8eaef023-2b34-4da1-9baa-8bc8c9d6a490",
+                strategy: PowAssent.Strategy.AzureOAuth2,
+              ]
+            ]
+
+  The resource that client should pull a token for defaults to
+  `https://graph.microsoft.com/`. It can be overridden with the
+  `resource` key (or the `authorization_params` key):
+
+      config :my_app, :pow_assent,
+        providers:
+            [
+              azure: [
+                client_id: "REPLACE_WITH_CLIENT_ID",
+                client_secret: "REPLACE_WITH_CLIENT_SECRET",
+                tenant_id: "8eaef023-2b34-4da1-9baa-8bc8c9d6a490",
+                resource: "https://service.contoso.com/",
+                strategy: PowAssent.Strategy.AzureOAuth2
+              ]
+            ]
+
+  ## Setting up Azure AD
+
+  Login to Azure, and set up a new application:
+  https://docs.microsoft.com/en-us/azure/active-directory/develop/v1-protocols-oauth-code#register-your-application-with-your-ad-tenant
+
+  * `client_id` is the "Application ID".
+  * `client_secret` has to be created with a new key for the application.
+  * The callback URL (http://localhost:4000/auth/azure/callback) should be
+    added to Reply URL's for the application
+  * "Sign in and read user profile" permission has to be enabled.
+  * To find the App ID URI to be used for `resource`, in the Azure Portal,
+    click Azure Active Directory, click Application registrations, open the
+    application's Settings page, then click Properties.
+  """
+  use PowAssent.Strategy.OAuth2.Base
+
+  @spec default_config(Keyword.t()) :: Keyword.t()
+  def default_config(config) do
+    tenant_id = Keyword.get(config, :tenant_id, "common")
+    resource = Keyword.get(config, :resource, "https://graph.microsoft.com/")
+
+    [
+      site: "https://login.microsoftonline.com",
+      authorize_url: "/#{tenant_id}/oauth2/authorize",
+      token_url: "/#{tenant_id}/oauth2/token",
+      authorization_params: [response_mode: "query", response_type: "code", resource: resource],
+      get_user_fn: &get_user/2
+    ]
+  end
+
+  @spec normalize(Client.t(), Keyword.t(), map()) :: {:ok, map()}
+  def normalize(_client, _config, user) do
+    {:ok, %{
+      "uid"        => user["sub"],
+      "name"       => user["name"],
+      "email"      => user["email"],
+      "first_name" => user["given_name"],
+      "last_name"  => user["family_name"]}}
+  end
+
+  @spec get_user(Keyword.t(), Client.t()) :: {:ok, map()}
+  def get_user(_config, client) do
+    user =
+      client.token.other_params["id_token"]
+      |> String.split(".")
+      |> Enum.at(1)
+      |> Base.decode64!(padding: false)
+      |> Poison.decode!()
+
+      {:ok, user}
+  end
+end

test/pow_assent/strategies/azure_oauth2.exs

@@ -0,0 +1,51 @@
+defmodule PowAssent.Strategy.AzureOAuth2 do
+  use PowAssent.Test.Phoenix.ConnCase
+
+  import OAuth2.TestHelpers
+  alias PowAssent.Strategy.AzureOAuth2
+
+  @access_token "access_token"
+
+  setup %{conn: conn} do
+    bypass = Bypass.open()
+    config = [site: bypass_server(bypass)]
+
+    {:ok, conn: conn, config: config, bypass: bypass}
+  end
+
+  test "authorize_url/2", %{conn: conn, config: config} do
+    assert {:ok, %{conn: _conn, url: url}} = AzureOAuth2.authorize_url(config, conn)
+    assert url =~ "/common/oauth2/authorize?client_id="
+
+    config = Keyword.put(config, :tenant_id, "8eaef023-2b34-4da1-9baa-8bc8c9d6a490")
+    assert {:ok, %{conn: _conn, url: url}} = AzureOAuth2.authorize_url(config, conn)
+    assert url =~ "/8eaef023-2b34-4da1-9baa-8bc8c9d6a490/oauth2/authorize?client_id="
+  end
+
+  describe "callback/2" do
+    setup %{conn: conn, config: config, bypass: bypass} do
+      params = %{"code" => "test", "redirect_uri" => "test"}
+
+      {:ok, conn: conn, config: config, params: params, bypass: bypass}
+    end
+
+    test "normalizes data", %{conn: conn, config: config, params: params, bypass: bypass} do
+      Bypass.expect_once(bypass, "POST", "/common/oauth2/token", fn conn ->
+         id_token = "eyJ0eXAiOiJKV1QiLCJhbGciOiJub25lIn0.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."
+
+         send_resp(conn, 200, Poison.encode!(%{access_token: @access_token, id_token: id_token}))
+      end)
+
+      expected = %{
+        "uid" => "JWvYdCWPhhlpS1Zsf7yYUxShUwtUm5yzPmw_-jX3fHY",
+        "name" => "Frank Miller",
+        "given_name" => "Frank",
+        "family_name" => "Miller",
+        "email" => "frank@contoso.com",
+      }
+
+      {:ok, %{user: user}} = AzureOAuth2.callback(config, conn, params)
+      assert expected == user
+    end
+  end
+end