LTI: add XAPI duration to enrollment activity time

Change-Id: I2e381a0a65b81d8f1ad31562b67caf74d5962f84
Reviewed-on: https://gerrit.instructure.com/37116
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Brad Humphrey <brad@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: Braden Anderson <braden@instructure.com>

app/controllers/lti_api_controller.rb

@@ -53,6 +53,25 @@ class LtiApiController < ApplicationController
     render :text => e.to_s, :status => 401
   end
 
+  def xapi
+    verify_oauth
+
+    if request.content_type != "application/json"
+      return render :text => '', :status => 415
+    end
+
+    source_id = params[:actor]['account']['name']
+    course, assignment, user = BasicLTI::BasicOutcomes.decode_source_id(@tool, source_id)
+
+    duration = params[:result]['duration']
+    seconds = duration.match(/PT(\d+)S/)[1].to_i
+
+    # TODO: This should create an asset user access and page view as well.
+    course.enrollments.where(:user_id => user).update_all(['total_activity_time = total_activity_time + ?', seconds])
+
+    return render :text => '', :status => 200
+  end
+
   protected
 
   def verify_oauth

config/routes.rb

@@ -1571,6 +1571,7 @@ CanvasRails::Application.routes.draw do
   ApiRouteSet.draw(self, "/api/lti/v1") do
     post "tools/:tool_id/grade_passback", :controller => :lti_api, :action => :grade_passback, :path_name => "lti_grade_passback_api"
     post "tools/:tool_id/ext_grade_passback", :controller => :lti_api, :action => :legacy_grade_passback, :path_name => "blti_legacy_grade_passback_api"
+    post "tools/:tool_id/xapi", :controller => :lti_api, :action => :xapi, :path_name => "lti_xapi"
   end
 
   ApiRouteSet.draw(self, "/api/lti") do

lib/lti/message_helper.rb

@@ -23,7 +23,8 @@ module Lti
   module MessageHelper
     def common_variable_substitutions
       {
-          '$Canvas.api.domain' => -> {HostUrl.context_host(@domain_root_account, request.host)}
+          '$Canvas.api.domain' => -> {HostUrl.context_host(@domain_root_account, request.host)},
+          '$Canvas.xapi.url' => -> {lti_xapi_url(@tool)}
       }
     end
   end