Add authentication for immersive reader

Test Plan:
  - Given the proper credentials in dynamic_settings.yml, calling
    /api/v1/immersive_reader/authenticate works

closes COREFE-263

flag = none

Change-Id: I2f42772691d7d64fb79229585ee9d008fa2ce2b6
Reviewed-on: https://gerrit.instructure.com/209911
Tested-by: Jenkins
Reviewed-by: Cameron Matheson <cameron@instructure.com>
QA-Review: Clay Diffrient <cdiffrient@instructure.com>
Product-Review: Clay Diffrient <cdiffrient@instructure.com>

app/controllers/immersive_reader_controller.rb

@@ -0,0 +1,67 @@
+#
+# Copyright (C) 2019 - present Instructure, Inc.
+#
+# This file is part of Canvas.
+#
+# Canvas is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, version 3 of the License.
+#
+# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+# @API Immersive Reader
+# @beta
+#
+# This API requires Immersive Reader to be configured
+
+class ImmersiveReaderController < ApplicationController
+
+  before_action :require_user
+  before_action :require_config
+
+  def ir_config
+    @ir_config ||= YAML.load(Canvas::DynamicSettings.find(tree: :private)['immersive_reader.yml'] || '{}')
+  end
+
+  def require_config
+    return render json: { message: 'Service not found' }, status: :not_found unless ir_config.present?
+  end
+
+  def service_url
+    "https://login.windows.net/#{ir_config[:ir_tenant_id]}/oauth2/token"
+  end
+
+  def headers
+    { "content-type": "application/x-www-form-urlencoded" }
+  end
+
+  def form
+    {
+      grant_type: "client_credentials",
+      client_id: ir_config[:ir_client_id],
+      client_secret: ir_config[:ir_client_secret],
+      resource: "https://cognitiveservices.azure.com/"
+    }
+  end
+
+  def authenticate
+    response = CanvasHttp.post(service_url, headers, form_data: form)
+    if response && response.code == '200'
+      parsed = JSON.parse(response.body)
+      render json: {
+        token: parsed["access_token"],
+        subdomain: ir_config[:ir_subdomain]
+      }
+    else
+      message = "Error connecting to cognitive services #{response}"
+      raise ServiceError, message
+    end
+  end
+end

config/routes.rb

@@ -1623,6 +1623,10 @@ CanvasRails::Application.routes.draw do
       post 'image_selection/:id', action: :image_selection
     end
 
+    scope(controller: :immersive_reader) do
+      get 'immersive_reader/authenticate', action: :authenticate
+    end
+
     scope(controller: :search) do
       get 'search/rubrics', action: 'rubrics', as: 'search_rubrics'
       get 'search/recipients', action: 'recipients', as: 'search_recipients'

spec/controllers/immersive_reader_controller_spec.rb

@@ -0,0 +1,57 @@
+#
+# Copyright (C) 2019 - present Instructure, Inc.
+#
+# This file is part of Canvas.
+#
+# Canvas is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, version 3 of the License.
+#
+# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+require 'spec_helper'
+require 'webmock/rspec'
+WebMock.disable_net_connect!(allow_localhost: true)
+
+describe ImmersiveReaderController do
+  it 'should require a user be logged in' do
+    get 'authenticate'
+    assert_unauthorized
+  end
+
+  it 'should require the plugin be configured' do
+    user_model
+    user_session(@user)
+    get 'authenticate'
+    assert_status(404)
+  end
+
+  it 'should authenticate with cognitive services' do
+    user_model
+    user_session(@user)
+    stub_request(:post, 'https://login.windows.net')
+    allow(controller).to receive(:ir_config).and_return(
+      {
+        ir_tenant_id: 'faketenantid',
+        ir_client_id: 'fakeclientid',
+        ir_client_secret: 'fakesecret',
+        ir_subdomain: 'fakesub'
+      }
+    )
+    get 'authenticate'
+    expect(WebMock).to have_requested(:post, 'https://login.windows.net/faketenantid/oauth2/token')
+      .with(
+      body:
+        'grant_type=client_credentials&client_id=fakeclientid&client_secret=fakesecret&resource=https%3A%2F%2Fcognitiveservices.azure.com%2F',
+      headers: { 'Content-Type' => 'application/x-www-form-urlencoded' }
+    )
+      .once
+  end
+end