Add live dashboard for teachers in the context of an exercise

This commit also adds the fundamentals for ActionCable

Gemfile

@@ -37,6 +37,7 @@ gem 'rest-client'
 gem 'rubyzip'
 gem 'mnemosyne-ruby'
 gem 'whenever', require: false
+gem 'rails-timeago'
 
 group :development, :staging do
   gem 'bootsnap', require: false

Gemfile.lock

@@ -255,6 +255,9 @@ GEM
     rails-i18n (5.1.3)
       i18n (>= 0.7, < 2)
       railties (>= 5.0, < 6)
+    rails-timeago (2.17.1)
+      actionpack (>= 3.1)
+      activesupport (>= 3.1)
     railties (5.2.2)
       actionpack (= 5.2.2)
       activesupport (= 5.2.2)
@@ -437,6 +440,7 @@ DEPENDENCIES
   rails (= 5.2.2)
   rails-controller-testing
   rails-i18n
+  rails-timeago
   ransack
   rest-client
   rspec-autotest

app/assets/javascripts/application.js

@@ -14,6 +14,8 @@
 //= require turbolinks
 //= require pagedown_bootstrap
 //= require d3
+//= require rails-timeago
+//= require locales/jquery.timeago.de.js
 //
 // lib/assets
 //= require flash

app/assets/javascripts/base.js

@@ -23,3 +23,9 @@ $.fn.scrollTo = function(selector) {
     scrollTop: $(selector).offset().top - $(this).offset().top + $(this).scrollTop()
   }, ANIMATION_DURATION);
 };
+
+$.fn.replaceWithPush = function(a) {
+    const $a = $(a);
+    this.replaceWith($a);
+    return $a;
+};

app/assets/javascripts/cable.js

@@ -0,0 +1,13 @@
+// Action Cable provides the framework to deal with WebSockets in Rails.
+// You can generate new channels where WebSocket features live using the `rails generate channel` command.
+//
+//= require action_cable
+//= require_self
+//= require_tree ./channels
+
+(function() {
+  this.App || (this.App = {});
+
+  App.cable = ActionCable.createConsumer();
+
+}).call(this);

app/assets/javascripts/channels/la_exercises.js

@@ -0,0 +1,33 @@
+$(document).on('turbolinks:load', function() {
+    if ($.isController('exercises') && $('.teacher_dashboard').isPresent()) {
+
+        const exercise_id = $('.teacher_dashboard').data().exerciseId;
+        const study_group_id = $('.teacher_dashboard').data().studyGroupId;
+
+        const specific_channel = { channel: "LaExercisesChannel", exercise_id: exercise_id, study_group_id: study_group_id };
+
+
+        App.la_exercise = App.cable.subscriptions.create(specific_channel, {
+            connected: function () {
+                // Called when the subscription is ready for use on the server
+            },
+
+            disconnected: function () {
+                // Called when the subscription has been terminated by the server
+            },
+
+            received: function (data) {
+                // Called when there's incoming data on the websocket for this channel
+                let $row = $('tr[data-id="' + data.id + '"]');
+                if ($row.length === 0) {
+                    $row = $($('#posted_rfcs')[0].insertRow(0));
+                }
+                $row = $row.replaceWithPush(data.html);
+                $row.find('time').timeago();
+                $row.click(function () {
+                    Turbolinks.visit($(this).data("href"));
+                });
+            }
+        });
+    }
+});

app/assets/stylesheets/base.css.scss

@@ -113,3 +113,7 @@ span.caret {
     -webkit-transform: perspective(120px) rotateX(-180deg) rotateY(-179.9deg);
   }
 }
+
+.table-row-clickable {
+  cursor: pointer;
+}

app/channels/application_cable/channel.rb

@@ -0,0 +1,4 @@
+module ApplicationCable
+  class Channel < ActionCable::Channel::Base
+  end
+end

app/channels/application_cable/connection.rb

@@ -0,0 +1,30 @@
+module ApplicationCable
+  class Connection < ActionCable::Connection::Base
+    identified_by :current_user
+
+    def connect
+      self.current_user = find_verified_user
+    end
+
+    def disconnect
+      # Any cleanup work needed when the cable connection is cut.
+    end
+
+    private
+
+    def session
+      # `session` is not available here, so that we need to use `cookies.encrypted` instead
+      cookies.encrypted[Rails.application.config.session_options[:key]].symbolize_keys
+    end
+
+    def find_verified_user
+      # Finding the current_user is similar to the code used in application_controller.rb#current_user
+      current_user = ExternalUser.find_by(id: session[:external_user_id]) || InternalUser.find_by(id: session[:user_id])
+      if current_user
+        current_user
+      else
+        reject_unauthorized_connection
+      end
+    end
+  end
+end

app/channels/la_exercises_channel.rb

@@ -0,0 +1,16 @@
+class LaExercisesChannel < ApplicationCable::Channel
+
+  def subscribed
+    stream_from specific_channel
+  end
+
+  def unsubscribed
+    stop_all_streams
+  end
+
+  private
+  def specific_channel
+    reject unless StudyGroupPolicy.new(current_user, StudyGroup.find_by(id: params[:study_group_id])).stream_la?
+    "la_exercises_#{params[:exercise_id]}_channel_study_group_#{params[:study_group_id]}"
+  end
+end

app/controllers/exercises_controller.rb

@@ -7,7 +7,7 @@ class ExercisesController < ApplicationController
 
   before_action :handle_file_uploads, only: [:create, :update]
   before_action :set_execution_environments, only: [:create, :edit, :new, :update]
-  before_action :set_exercise_and_authorize, only: MEMBER_ACTIONS + [:clone, :implement, :working_times, :intervention, :search, :run, :statistics, :submit, :reload, :feedback]
+  before_action :set_exercise_and_authorize, only: MEMBER_ACTIONS + [:clone, :implement, :working_times, :intervention, :search, :run, :statistics, :submit, :reload, :feedback, :study_group_dashboard]
   before_action :set_external_user_and_authorize, only: [:statistics]
   before_action :set_file_types, only: [:create, :edit, :new, :update]
   before_action :set_course_token, only: [:implement]
@@ -475,4 +475,13 @@ class ExercisesController < ApplicationController
     end
   end
 
+  def study_group_dashboard
+    authorize!
+    @study_group_id = params[:study_group_id]
+    @request_for_comments = RequestForComment.
+            where(exercise: @exercise).includes(:submission).
+            where(submissions: {study_group_id: @study_group_id}).
+            order(created_at: :desc)
+  end
+
 end

app/controllers/request_for_comments_controller.rb

@@ -143,7 +143,7 @@ class RequestForCommentsController < ApplicationController
     # Never trust parameters from the scary internet, only allow the white list through.
     def request_for_comment_params
       # The study_group_id might not be present in the session (e.g. for internal users), resulting in session[:study_group_id] = nil which is intended.
-      params.require(:request_for_comment).permit(:exercise_id, :file_id, :question, :requested_at, :solved, :submission_id).merge(user_id: current_user.id, user_type: current_user.class.name, study_group_id: session[:study_group_id])
+      params.require(:request_for_comment).permit(:exercise_id, :file_id, :question, :requested_at, :solved, :submission_id).merge(user_id: current_user.id, user_type: current_user.class.name)
     end
 
     def comment_params

app/controllers/submissions_controller.rb

@@ -201,6 +201,8 @@ class SubmissionsController < ApplicationController
     save_run_output
 
     if @run_output.blank?
+      @raw_output ||= ''
+      @run_output ||= ''
       parse_message t('exercises.implement.no_output', timestamp: l(Time.now, format: :short)), 'stdout', tubesock
     end
 

app/helpers/action_cable_helper.rb

@@ -0,0 +1,15 @@
+module ActionCableHelper
+  def trigger_rfc_action_cable
+    if submission.study_group_id.present?
+      ActionCable.server.broadcast(
+        "la_exercises_#{exercise_id}_channel_study_group_#{submission.study_group_id}",
+        id: id,
+        html: (ApplicationController.render(partial: 'request_for_comments/list_entry',
+                                            locals: {request_for_comment: self})))
+    end
+  end
+
+  def trigger_rfc_action_cable_from_comment
+    RequestForComment.find_by(submission: file.context).trigger_rfc_action_cable
+  end
+end

app/models/comment.rb

@@ -1,8 +1,12 @@
 class Comment < ApplicationRecord
   # inherit the creation module: encapsulates that this is a polymorphic user, offers some aliases and makes sure that all necessary attributes are set.
   include Creation
+  include ActionCableHelper
+
   attr_accessor :username, :date, :updated, :editable
 
   belongs_to :file, class_name: 'CodeOcean::File'
   belongs_to :user, polymorphic: true
+
+  after_save :trigger_rfc_action_cable_from_comment
 end

app/models/request_for_comment.rb

@@ -1,5 +1,7 @@
 class RequestForComment < ApplicationRecord
   include Creation
+  include ActionCableHelper
+
   belongs_to :submission
   belongs_to :exercise
   belongs_to :file, class_name: 'CodeOcean::File'
@@ -10,6 +12,8 @@ class RequestForComment < ApplicationRecord
   scope :unsolved, -> { where(solved: [false, nil]) }
   scope :in_range, -> (from, to) { where(created_at: from..to) }
 
+  after_save :trigger_rfc_action_cable
+
     def self.last_per_user(n = 5)
       from("(#{row_number_user_sql}) as request_for_comments")
           .where("row_number <= ?", n)

app/policies/exercise_policy.rb

@@ -3,8 +3,8 @@ class ExercisePolicy < AdminOrAuthorPolicy
     admin?
   end
 
-  def show?
-    admin? || teacher?
+  [:show?, :study_group_dashboard?].each do |action|
+    define_method(action) { admin? || teacher? }
   end
 
   [:clone?, :destroy?, :edit?, :statistics?, :update?, :feedback?].each do |action|

app/policies/study_group_policy.rb

@@ -3,8 +3,8 @@ class StudyGroupPolicy < AdminOnlyPolicy
     admin? || teacher?
   end
 
-  [:show?, :destroy?, :edit?, :update?].each do |action|
-    define_method(action) { admin? || @user.teacher? && @record.users.include?(@user) }
+  [:show?, :destroy?, :edit?, :update?, :stream_la?].each do |action|
+    define_method(action) { admin? || @user.teacher? && @record.present? && @record.users.include?(@user) }
   end
 
   class Scope < Scope

app/views/exercises/study_group_dashboard.html.slim

@@ -0,0 +1,21 @@
+h1
+  = t('.live_dashboard')
+
+div.teacher_dashboard data-exercise-id="#{@exercise.id}" data-study-group-id="#{@study_group_id}"
+
+h4
+  = t('.related_requests_for_comments')
+
+.table-responsive
+  table.table.table-hover.mt-4
+    thead
+      tr
+        th.text-center
+          i.mr-0 class="fa fa-lightbulb-o" aria-hidden="true" title = t('request_for_comments.solved')
+        th.text-center
+          i.mr-0 class="fa fa-comment" aria-hidden="true" title = t('request_for_comments.comments') align="center"
+        th.col-12 = t('activerecord.attributes.request_for_comments.question')
+        th = t('activerecord.attributes.request_for_comments.username')
+        th.text-nowrap = t('activerecord.attributes.request_for_comments.requested_at')
+      tbody#posted_rfcs
+        = render(partial: 'request_for_comments/list_entry', collection: @request_for_comments, as: :request_for_comment)

app/views/layouts/application.html.slim

@@ -5,6 +5,7 @@ html lang='en'
     meta name='viewport' content='width=device-width, initial-scale=1'
     title = application_name
     link href=asset_path('favicon.png') rel='icon' type='image/png'
+    = action_cable_meta_tag
     = stylesheet_pack_tag('application', media: 'all', 'data-turbolinks-track': true)
     = stylesheet_pack_tag('stylesheets', media: 'all', 'data-turbolinks-track': true)
     = stylesheet_link_tag('application', media: 'all', 'data-turbolinks-track': true)
@@ -12,6 +13,7 @@ html lang='en'
     = javascript_include_tag('application', 'data-turbolinks-track': true)
     = yield(:head)
     = csrf_meta_tags
+    = timeago_script_tag
   body
     - unless @embed_options[:hide_navbar]
       nav.navbar.navbar-dark.bg-dark.navbar-expand-md.mb-4.py-1 role='navigation'

app/views/request_for_comments/_list_entry.html.slim

@@ -0,0 +1,15 @@
+tr.table-row-clickable data-id=request_for_comment.id data-href=request_for_comment_path(request_for_comment)
+  td.p-2
+    - if request_for_comment.solved?
+      span.fa.fa-check.fa-2x.text-success aria-hidden="true"
+    - elsif request_for_comment.full_score_reached
+      span.fa.fa-check.fa-2x style="color:darkgrey" aria-hidden="true"
+    - else
+      = ''
+  td.text-center = request_for_comment.comments_count
+  - if request_for_comment.has_attribute?(:question) && request_for_comment.question.present?
+    td.text-primary = truncate(request_for_comment.question, length: 200)
+  - else
+    td.text-black-50.font-italic = t('request_for_comments.no_question')
+  td = request_for_comment.user
+  td = timeago_tag request_for_comment.created_at

config/application.rb

@@ -28,5 +28,7 @@ module CodeOcean
     config.autoload_paths << Rails.root.join('lib')
     config.eager_load_paths << Rails.root.join('lib')
     config.assets.precompile += %w( markdown-buttons.png )
+
+    config.action_cable.mount_path = '/cable'
   end
 end

config/locales/de.yml

@@ -101,6 +101,7 @@ de:
         files: Dateien
         score: Punktzahl
         user: Autor
+        study_group: Lerngruppe
       study_group:
         name: Name
         external_id: Externe ID
@@ -347,6 +348,7 @@ de:
       implement: Implementieren
       test_files: Test-Dateien
       feedback: Feedback
+      study_group_dashboard: Live Dashboard
     statistics:
       average_score: Durchschnittliche Punktzahl
       final_submissions: Finale Abgaben
@@ -365,6 +367,9 @@ de:
       failure: Beim Übermitteln Ihrer Punktzahl ist ein Fehler aufgetreten. Bitte versuchen Sie es später erneut.
       full_score_redirect_to_rfc: Herzlichen Glückwunsch! Sie haben die maximale Punktzahl für diese Aufgabe an den Kurs übertragen. Ein anderer Teilnehmer hat eine Frage zu der von Ihnen gelösten Aufgabe. Er würde sich sicherlich sehr über ihre Hilfe und Kommentare freuen.
       full_score_redirect_to_own_rfc: Herzlichen Glückwunsch! Sie haben die maximale Punktzahl für diese Aufgabe an den Kurs übertragen. Ihre Frage ist damit wahrscheinlich gelöst? Falls ja, fügen Sie doch den entscheidenden Kniff als Antwort hinzu und markieren die Frage als gelöst, bevor sie das Fenster schließen.
+    study_group_dashboard:
+      live_dashboard: Live Dashboard
+      related_requests_for_comments: Zugehörige Kommentaranfragen
     external_users:
       statistics:
         no_data_available: Keine Daten verfügbar.

config/locales/en.yml

@@ -101,6 +101,7 @@ en:
         files: Files
         score: Score
         user: Author
+        study_group: Study Group
       study_group:
         name: Name
         external_id: External ID
@@ -347,6 +348,7 @@ en:
       implement: Implement
       test_files: Test Files
       feedback: Feedback
+      study_group_dashboard: Live Dashboard
     statistics:
       average_score: Average Score
       final_submissions: Final Submissions
@@ -365,6 +367,9 @@ en:
       failure: An error occurred while transmitting your score. Please try again later.
       full_score_redirect_to_rfc: Congratulations! You achieved and submitted the highest possible score for this exercise. Another participant has a question concerning the exercise you just solved. Your help and comments will be greatly appreciated!
       full_score_redirect_to_own_rfc: Congratulations! You achieved and submitted the highest possible score for this exercise. Your question concerning the exercise is solved? If so, please share the essential insight with your fellows and mark the question as solved, before you close this window!
+    study_group_dashboard:
+      live_dashboard: Live Dashboard
+      related_requests_for_comments: Related Requests for Comments
     external_users:
       statistics:
         no_data_available: No data available.

config/routes.rb

@@ -83,6 +83,7 @@ Rails.application.routes.draw do
       get :feedback
       get :reload
       post :submit
+      get 'study_group_dashboard/:study_group_id', to: 'exercises#study_group_dashboard'
     end
   end
 
@@ -151,4 +152,5 @@ Rails.application.routes.draw do
 
   post "/evaluate", to: 'remote_evaluation#evaluate', via: [:post]
 
+  mount ActionCable.server => '/cable'
 end

db/migrate/20190213131802_add_indices_for_request_for_comments.rb

@@ -0,0 +1,6 @@
+class AddIndicesForRequestForComments < ActiveRecord::Migration[5.2]
+  def change
+    add_index :request_for_comments, :submission_id
+    add_index :request_for_comments, :exercise_id
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_11_29_093207) do
+ActiveRecord::Schema.define(version: 2019_02_13_131802) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -292,6 +292,8 @@ ActiveRecord::Schema.define(version: 2018_11_29_093207) do
     t.text "thank_you_note"
     t.boolean "full_score_reached", default: false
     t.integer "times_featured", default: 0
+    t.index ["exercise_id"], name: "index_request_for_comments_on_exercise_id"
+    t.index ["submission_id"], name: "index_request_for_comments_on_submission_id"
   end
 
   create_table "searches", force: :cascade do |t|
@@ -415,4 +417,5 @@ ActiveRecord::Schema.define(version: 2018_11_29_093207) do
     t.index ["user_type", "user_id"], name: "index_user_proxy_exercise_exercises_on_user_type_and_user_id"
   end
 
+  add_foreign_key "submissions", "study_groups"
 end