Faster Course#show for v8

Simplify v8 course info

Do not return unlockables from v8 api

Instance var to regular var in course data core

Remove submission information from v8 core courses

Faster visible to in core course information

Use precomputed unlocks in course info

Author: nygrenh

app/controllers/api/v8/core/courses_controller.rb

@@ -33,7 +33,7 @@ def show
           course = Course.find_by!(id: params[:id])
           authorize! :read, course
           data = { course: CourseInfo.new(current_user, view_context).course_data_core_api(course) }
-          present data
+          render json: data
         end
       end
     end

app/models/exercise.rb

@@ -188,7 +188,11 @@ def submittable_by?(user)
   # Whether a user may see all metadata about the exercise
   def visible_to?(user)
     user.administrator? || user.teacher?(course.organization) || user.assistant?(course) ||
-      (!hidden? && !disabled? && published? && unlock_spec_obj.permits_unlock_for?(user))
+      _fast_visible_to?(user) && unlock_spec_obj.permits_unlock_for?(user)
+  end
+
+  def _fast_visible_to?(user)
+    !hidden? && !disabled? && published?
   end
 
   # Whether the user may see the scoreboard for the exercise

lib/course_info.rb

@@ -31,24 +31,38 @@ def course_data(organization, course, opts = {})
   end
 
   def course_data_core_api(course)
-    exercises = course.exercises.includes(:course, :available_points).to_a.natsort_by(&:name)
-
+    UncomputedUnlock.resolve(course, @user)
     @unlocked_exercises = course.unlocks
                               .where(user_id: @user.id)
                               .where(['valid_after IS NULL OR valid_after < ?', Time.now])
                               .pluck(:exercise_name)
 
-    submissions_by_exercise = {}
-    Submission.where(course_id: course.id, user_id: @user.id).each do |sub|
-      submissions_by_exercise[sub.exercise_name] ||= []
-      submissions_by_exercise[sub.exercise_name] << sub
-    end
-    exercises.each do |ex|
-      ex.set_submissions_by(@user, submissions_by_exercise[ex.name] || [])
+    exercises = course.exercises.includes(:course, :available_points)
+
+    unless @user.administrator? || @user.teacher?(course.organization) || @user.assistant?(course)
+      exercises = exercises.where(hidden: false, disabled_status: 0)
+      exercises = if @unlocked_exercises.empty?
+        exercises.where(unlock_spec: nil)
+      else
+        exercises.where(["unlock_spec IS NULL OR name IN (#{@unlocked_exercises.map {|_| '?'}.join(', ')})", *@unlocked_exercises])
+      end.select { |e| e._fast_visible_to?(@user)}
     end
 
-    @course_list.course_data_core_api(course).merge(unlockables: course.unlockable_exercises_for(@user).map(&:name).natsort,
-                                                               exercises: exercises.map { |ex| exercise_data_core_api(ex) }.reject(&:nil?))
+    exercises = exercises.to_a.natsort_by(&:name)
+
+    {
+      id: course.id,
+      name: course.name,
+      title: course.title,
+      description: course.description,
+      details_url: @helpers.api_v8_core_course_url(course),
+      unlock_url: @helpers.api_v8_core_course_unlock_url(course),
+      reviews_url: @helpers.api_v8_core_course_reviews_url(course),
+      comet_url: CometServer.get.client_url,
+      spyware_urls: SiteSetting.value('spyware_servers'),
+      unlockables: [],
+      exercises: exercises.map { |ex| exercise_data_core_api(ex) }
+    }
   end
 
   private
@@ -94,8 +108,6 @@ def exercise_data(exercise)
   end
 
   def exercise_data_core_api(exercise)
-    return nil unless exercise.visible_to?(@user)
-
     # optimization: use @unlocked_exercises to avoid querying unlocks repeatedly
     locked = exercise.requires_unlock? && !@unlocked_exercises.include?(exercise.name)
 
@@ -122,10 +134,6 @@ def exercise_data_core_api(exercise)
     }
 
     data[:solution_zip_url] = @helpers.download_api_v8_core_exercise_solution_url(exercise) if @user.administrator?
-    data[:exercise_submissions_url] = @helpers.api_v8_core_exercise_url(exercise, format: 'json')
-    last_submission = get_latest_submission(exercise)
-    data[:latest_submission_url] = @helpers.download_api_v8_core_submission_url(last_submission) unless last_submission.nil?
-    data[:latest_submission_id] = last_submission.id unless last_submission.nil?
 
     data
   end

lib/course_list.rb

@@ -52,22 +52,6 @@ def course_data(organization, course, opts={})
       data
   end
 
-  def course_data_core_api(course)
-    @course = course
-    data = {
-        id: course.id,
-        name: course.name,
-        title: course.title,
-        description: course.description,
-        details_url: @helpers.api_v8_core_course_url(course),
-        unlock_url: @helpers.api_v8_core_course_unlock_url(course),
-        reviews_url: @helpers.api_v8_core_course_reviews_url(course),
-        comet_url: CometServer.get.client_url,
-        spyware_urls: SiteSetting.value('spyware_servers'),
-    }
-    data
-  end
-
   private
   def exercises
     @exercises ||= @course.exercises.select { |e| e.points_visible_to?(@user) }