258 lines
8.8 KiB
Ruby
258 lines
8.8 KiB
Ruby
# frozen_string_literal: true
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require 'oauth/request_proxy/rack_request'
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module Lti
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extend ActiveSupport::Concern
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include LtiHelper
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MAXIMUM_SCORE = 1
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MAXIMUM_SESSION_AGE = 60.minutes
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SESSION_PARAMETERS = %w[launch_presentation_return_url lis_outcome_service_url lis_result_sourcedid].freeze
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def build_tool_provider(options = {})
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if options[:consumer] && options[:parameters]
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IMS::LTI::ToolProvider.new(options[:consumer].oauth_key, options[:consumer].oauth_secret, options[:parameters])
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end
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end
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private :build_tool_provider
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# exercise_id.nil? ==> the user has logged out. All session data is to be destroyed
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# exercise_id.exists? ==> the user has submitted the results of an exercise to the consumer.
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# Only the lti_parameters are deleted.
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def clear_lti_session_data(exercise_id = nil, user_id = nil)
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if exercise_id.nil?
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session.delete(:external_user_id)
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session.delete(:study_group_id)
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session.delete(:embed_options)
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session.delete(:lti_exercise_id)
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session.delete(:lti_parameters_id)
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end
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LtiParameter.where(external_users_id: user_id,
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exercises_id: exercise_id).destroy_all
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end
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private :clear_lti_session_data
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def consumer_return_url(provider, options = {})
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consumer_return_url = provider.try(:launch_presentation_return_url) || params[:launch_presentation_return_url]
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consumer_return_url += "?#{options.to_query}" if consumer_return_url && options.present?
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consumer_return_url
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end
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def external_user_email(provider)
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provider.lis_person_contact_email_primary
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end
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private :external_user_email
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def external_user_name(provider)
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# save person_name_full if supplied. this is the display_name, if it is set.
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# else only save the firstname, we don't want lastnames (family names)
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provider.lis_person_name_full || provider.lis_person_name_given
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end
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private :external_user_name
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def external_user_role(provider)
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result = 'learner'
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if provider.roles.present?
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provider.roles.each do |role|
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case role.downcase
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when 'administrator'
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# We don't want anyone to get admin privileges through LTI
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result = 'teacher' if result == 'learner'
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when 'instructor'
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result = 'teacher' if result == 'learner'
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else # 'learner'
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next
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end
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end
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end
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result
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end
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def context_id?
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# All platforms (except HPI Schul-Cloud) set the context_id
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params[:context_id]
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end
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def refuse_lti_launch(options = {})
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return_to_consumer(lti_errorlog: options[:message], lti_errormsg: t('sessions.oauth.failure'))
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end
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private :refuse_lti_launch
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def require_oauth_parameters
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refuse_lti_launch(message: t('sessions.oauth.missing_parameters')) unless params[:oauth_consumer_key] && params[:oauth_signature]
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end
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private :require_oauth_parameters
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def require_unique_oauth_nonce
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refuse_lti_launch(message: t('sessions.oauth.used_nonce')) if NonceStore.has?(params[:oauth_nonce])
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end
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private :require_unique_oauth_nonce
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def require_valid_consumer_key
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@consumer = Consumer.find_by(oauth_key: params[:oauth_consumer_key])
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refuse_lti_launch(message: t('sessions.oauth.invalid_consumer')) unless @consumer
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end
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private :require_valid_consumer_key
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def require_valid_exercise_token
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proxy_exercise = ProxyExercise.find_by(token: params[:custom_token])
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@exercise = if proxy_exercise.nil?
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Exercise.find_by(token: params[:custom_token])
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else
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proxy_exercise.get_matching_exercise(@current_user)
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end
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session[:lti_exercise_id] = @exercise.id if @exercise
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refuse_lti_launch(message: t('sessions.oauth.invalid_exercise_token')) unless @exercise
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end
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private :require_valid_exercise_token
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def require_valid_oauth_signature
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@provider = build_tool_provider(consumer: @consumer, parameters: params)
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refuse_lti_launch(message: t('sessions.oauth.invalid_signature')) unless @provider.valid_request?(request)
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end
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private :require_valid_oauth_signature
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def return_to_consumer(options = {})
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consumer_return_url = @provider.try(:launch_presentation_return_url) || params[:launch_presentation_return_url]
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if consumer_return_url
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consumer_return_url += "?#{options.to_query}" if options.present?
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redirect_to(consumer_return_url)
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else
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flash[:danger] = options[:lti_errormsg]
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flash[:info] = options[:lti_msg]
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redirect_to(:root)
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end
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end
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private :return_to_consumer
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def send_score(submission)
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::NewRelic::Agent.add_custom_attributes({score: submission.normalized_score, session: session})
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unless (0..MAXIMUM_SCORE).cover?(submission.normalized_score)
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raise Error.new("Score #{submission.normalized_score} must be between 0 and #{MAXIMUM_SCORE}!")
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end
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if submission.user.consumer
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lti_parameter = LtiParameter.where(consumers_id: submission.user.consumer.id,
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external_users_id: submission.user_id,
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exercises_id: submission.exercise_id).last
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provider = build_tool_provider(consumer: submission.user.consumer, parameters: lti_parameter.lti_parameters)
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end
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if provider.nil?
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{status: 'error'}
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elsif provider.outcome_service?
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Sentry.set_extras({
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provider: provider.inspect,
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score: submission.normalized_score,
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lti_parameter: lti_parameter.inspect,
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session: session.to_hash,
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exercise_id: submission.exercise_id,
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})
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normalized_lit_score = submission.normalized_score
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if submission.before_deadline?
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# Keep the full score
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elsif submission.within_grace_period?
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# Reduce score by 20%
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normalized_lit_score *= 0.8
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elsif submission.after_late_deadline?
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# Reduce score by 100%
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normalized_lit_score *= 0.0
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end
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response = provider.post_replace_result!(normalized_lit_score)
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{code: response.response_code, message: response.post_response.body, status: response.code_major,
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score_sent: normalized_lit_score}
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else
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{status: 'unsupported'}
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end
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end
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private :send_score
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def set_current_user
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@current_user = ExternalUser.find_or_create_by(consumer_id: @consumer.id, external_id: @provider.user_id)
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external_role = external_user_role(@provider)
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internal_role = @current_user.role
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desired_role = internal_role == 'admin' ? internal_role : external_role
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# Update user with new information but change the role only if he is no admin user
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@current_user.update(email: external_user_email(@provider), name: external_user_name(@provider), role: desired_role)
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end
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private :set_current_user
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def set_study_group_membership
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group = if context_id?
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# Ensure to find the group independent of the name and set it only once.
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StudyGroup.find_or_create_by(external_id: @provider.context_id, consumer: @consumer) do |new_group|
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new_group.name = @provider.context_title
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end
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else
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StudyGroup.find_or_create_by(external_id: @provider.resource_link_id, consumer: @consumer)
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end
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group.external_users << @current_user unless group.external_users.include? @current_user
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group.save
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session[:study_group_id] = group.id
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end
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def set_embedding_options
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@embed_options = {}
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%i[hide_navbar
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hide_exercise_description
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collapse_exercise_description
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disable_run
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disable_score
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disable_rfc
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disable_redirect_to_rfcs
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disable_redirect_to_feedback
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disable_interventions
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hide_sidebar
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read_only
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hide_test_results
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disable_hints
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disable_download].each do |option|
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value = params["custom_embed_options_#{option}".to_sym] == 'true'
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# Optimize storage and save only those that are true, the session cookie is limited to 4KB
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@embed_options[option] = value if value.present?
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end
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session[:embed_options] = @embed_options
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end
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private :set_embedding_options
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def store_lti_session_data(options = {})
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lti_parameters = LtiParameter.find_or_create_by(consumers_id: options[:consumer].id,
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external_users_id: @current_user.id,
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exercises_id: @exercise.id)
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lti_parameters.lti_parameters = options[:parameters].slice(*SESSION_PARAMETERS).permit!.to_h
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lti_parameters.save!
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@lti_parameters = lti_parameters
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session[:external_user_id] = @current_user.id
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session[:lti_parameters_id] = lti_parameters.id
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end
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private :store_lti_session_data
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def store_nonce(nonce)
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NonceStore.add(nonce)
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end
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private :store_nonce
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class Error < RuntimeError
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end
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end
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