Implement support for some basic embed options for work sheets via LTI

This commit also fixes an issue with the flash messages being positioned too high and displayed for too long

app/controllers/application_controller.rb

@@ -5,7 +5,7 @@ class ApplicationController < ActionController::Base
   MEMBER_ACTIONS = [:destroy, :edit, :show, :update]
 
   after_action :verify_authorized, except: [:help, :welcome]
-  before_action :set_locale, :allow_iframe_requests
+  before_action :set_locale, :allow_iframe_requests, :load_embed_options
   protect_from_forgery(with: :exception, prepend: true)
   rescue_from Pundit::NotAuthorizedError, with: :render_not_authorized
 
@@ -38,4 +38,14 @@ class ApplicationController < ActionController::Base
   def allow_iframe_requests
     response.headers.delete('X-Frame-Options')
   end
+
+  def load_embed_options
+    if session[:embed_options].present? && session[:embed_options].is_a?(Hash)
+      @embed_options = session[:embed_options].symbolize_keys
+    else
+      @embed_options = {}
+    end
+    @embed_options
+  end
+  private :load_embed_options
 end

app/controllers/concerns/lti.rb

@@ -22,6 +22,7 @@ module Lti
     if (exercise_id.nil?)
       session.delete(:consumer_id)
       session.delete(:external_user_id)
+      session.delete(:embed_options)
     else
       LtiParameter.where(consumers_id: consumer_id,
                          external_users_id: user_id,
@@ -133,6 +134,26 @@ module Lti
   end
   private :set_current_user
 
+  def set_embedding_options
+    @embed_options = {}
+    [:hide_navbar,
+     :hide_exercise_description,
+     :disable_run,
+     :disable_score,
+     :disable_rfc,
+     :disable_interventions,
+     :hide_sidebar,
+     :read_only,
+     :hide_test_results,
+     :disable_hints].each do |option|
+      value = params["custom_embed_options_#{option}".to_sym] == 'true'
+      # Optimize storage and save only those that are true, the session cookie is limited to 4KB
+      @embed_options[option] = value if value.present?
+    end
+    session[:embed_options] = @embed_options
+  end
+  private :set_embedding_options
+
   def store_lti_session_data(options = {})
     lti_parameters = LtiParameter.find_or_create_by(consumers_id: options[:consumer].id,
                                                     external_users_id: @current_user.id,

app/controllers/concerns/submission_scoring.rb

@@ -55,6 +55,11 @@ module SubmissionScoring
         }
       end
     end
+    if @embed_options.present? && @embed_options[:hide_test_results] && outputs.present?
+      outputs.each do |output|
+        output.except!(:error_messages, :count, :failed, :filename, :message, :passed, :stderr, :stdout)
+      end
+    end
     outputs
   end
 end

app/controllers/exercises_controller.rb

@@ -188,7 +188,15 @@ class ExercisesController < ApplicationController
     user_got_intervention_in_exercise = UserExerciseIntervention.where(user: current_user, exercise: @exercise).size >= max_intervention_count_per_exercise
     user_got_enough_interventions = count_interventions_today >= max_intervention_count_per_day or user_got_intervention_in_exercise
 
-    @show_rfc_interventions = (not user_solved_exercise and not user_got_enough_interventions).to_s
+    unless @embed_options[:disable_interventions]
+      @show_rfc_interventions = (not user_solved_exercise and not user_got_enough_interventions).to_s
+      @show_break_interventions = false
+    else
+      @show_rfc_interventions = false
+      @show_break_interventions = false
+    end
+
+    @hide_rfc_button = @embed_options[:disable_rfc]
 
 
     @search = Search.new

app/controllers/flowr_controller.rb

@@ -8,7 +8,7 @@ class FlowrController < ApplicationController
                      .order('testruns.created_at DESC').first
 
     # Return if no submission was found
-    if submission.blank?
+    if submission.blank? || @embed_options[:disable_hints] || @embed_options[:hide_test_results]
       skip_authorization
       render json: [], status: :ok
       return

app/controllers/request_for_comments_controller.rb

@@ -96,6 +96,10 @@ class RequestForCommentsController < ApplicationController
   # POST /request_for_comments
   # POST /request_for_comments.json
   def create
+    # Consider all requests as JSON
+    request.format = 'json'
+    raise Pundit::NotAuthorizedError if @embed_options[:disable_rfc]
+
     @request_for_comment = RequestForComment.new(request_for_comment_params)
     respond_to do |format|
       if @request_for_comment.save

app/controllers/sessions_controller.rb

@@ -1,7 +1,7 @@
 class SessionsController < ApplicationController
   include Lti
 
-  [:require_oauth_parameters, :require_valid_consumer_key, :require_valid_oauth_signature, :require_unique_oauth_nonce, :set_current_user, :require_valid_exercise_token].each do |method_name|
+  [:require_oauth_parameters, :require_valid_consumer_key, :require_valid_oauth_signature, :require_unique_oauth_nonce, :set_current_user, :require_valid_exercise_token, :set_embedding_options].each do |method_name|
     before_action(method_name, only: :create_through_lti)
   end
 

app/controllers/submissions_controller.rb

@@ -129,6 +129,11 @@ class SubmissionsController < ApplicationController
     # end
 
     hijack do |tubesock|
+      if @embed_options[:disable_run]
+        kill_socket(tubesock)
+        return
+      end
+
       # probably add:
       # ensure
       #   #guarantee that the thread is releasing the DB connection after it is done
@@ -291,6 +296,11 @@ class SubmissionsController < ApplicationController
 
   def score
     hijack do |tubesock|
+      if @embed_options[:disable_score]
+        kill_socket(tubesock)
+        return
+      end
+
       Thread.new { EventMachine.run } unless EventMachine.reactor_running? && EventMachine.reactor_thread.alive?
       # tubesock is the socket to the client
 
@@ -308,6 +318,7 @@ class SubmissionsController < ApplicationController
   end
 
   def send_hints(tubesock, errors)
+    return if @embed_options[:disable_hints]
     errors = errors.to_a.uniq { |e| e.hint}
     errors.each do | error |
       tubesock.send_data JSON.dump({cmd: 'hint', hint: error.hint, description: error.error_template.description})