canvas-lms/lib/lti/substitutions_helper.rb

#
# Copyright (C) 2014 - present Instructure, Inc.
#
# This file is part of Canvas.
#
# Canvas is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
#

# Filters added to this controller apply to all controllers in the application.
# Likewise, all the methods added will be available for all controllers.

module Lti
  class SubstitutionsHelper
    LIS_ROLE_MAP = {
        'user' => LtiOutbound::LTIRoles::System::USER,
        'siteadmin' => LtiOutbound::LTIRoles::System::SYS_ADMIN,

        'teacher' => LtiOutbound::LTIRoles::Institution::INSTRUCTOR,
        'student' => LtiOutbound::LTIRoles::Institution::STUDENT,
        'admin' => LtiOutbound::LTIRoles::Institution::ADMIN,
        'observer' => LtiOutbound::LTIRoles::Context::OBSERVER,
        AccountUser => LtiOutbound::LTIRoles::Institution::ADMIN,

        StudentEnrollment => LtiOutbound::LTIRoles::Context::LEARNER,
        TeacherEnrollment => LtiOutbound::LTIRoles::Context::INSTRUCTOR,
        TaEnrollment => LtiOutbound::LTIRoles::Context::TEACHING_ASSISTANT,
        DesignerEnrollment => LtiOutbound::LTIRoles::Context::CONTENT_DEVELOPER,
        ObserverEnrollment => LtiOutbound::LTIRoles::Context::OBSERVER,
        StudentViewEnrollment => LtiOutbound::LTIRoles::Context::LEARNER
    }

    LIS_V2_ROLE_MAP = {
      'user' => 'http://purl.imsglobal.org/vocab/lis/v2/system/person#User',
      'siteadmin' => 'http://purl.imsglobal.org/vocab/lis/v2/system/person#SysAdmin',

      'teacher' => 'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Instructor',
      'student' => 'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Student',
      'admin' => 'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Administrator',
      AccountUser => 'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Administrator',
      TaEnrollment => ['http://purl.imsglobal.org/vocab/lis/v2/membership/instructor#TeachingAssistant', 'http://purl.imsglobal.org/vocab/lis/v2/membership#Instructor'],
      StudentEnrollment => 'http://purl.imsglobal.org/vocab/lis/v2/membership#Learner',
      TeacherEnrollment => 'http://purl.imsglobal.org/vocab/lis/v2/membership#Instructor',
      DesignerEnrollment => 'http://purl.imsglobal.org/vocab/lis/v2/membership#ContentDeveloper',
      ObserverEnrollment => 'http://purl.imsglobal.org/vocab/lis/v2/membership#Mentor',
      StudentViewEnrollment => 'http://purl.imsglobal.org/vocab/lis/v2/membership#Learner',
      Course => 'http://purl.imsglobal.org/vocab/lis/v2/course#CourseOffering'
    }

    LIS_V2_ROLE_NONE = 'http://purl.imsglobal.org/vocab/lis/v2/person#None'

    # Nearly identical to LIS_V2_ROLE_MAP except:
    #   1. Corrects typo in first TaEnrollment URI ('instructor'->'Instructor')
    #   2. Values uniformly (frozen) Arrays
    #   3. Has Group roles
    #   4. Has no Course role
    LIS_V2_LTI_ADVANTAGE_ROLE_MAP = {
      'user' => [ 'http://purl.imsglobal.org/vocab/lis/v2/system/person#User' ].freeze,
      'siteadmin' => [ 'http://purl.imsglobal.org/vocab/lis/v2/system/person#SysAdmin' ].freeze,

      'teacher' => [ 'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Instructor' ].freeze,
      'student' => [ 'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Student' ].freeze,
      'admin' => [ 'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Administrator' ].freeze,
      AccountUser => [ 'http://purl.imsglobal.org/vocab/lis/v2/institution/person#Administrator' ].freeze,
      TaEnrollment => [
        'http://purl.imsglobal.org/vocab/lis/v2/membership/Instructor#TeachingAssistant',
        'http://purl.imsglobal.org/vocab/lis/v2/membership#Instructor'
      ].freeze,
      StudentEnrollment => [ 'http://purl.imsglobal.org/vocab/lis/v2/membership#Learner' ].freeze,
      TeacherEnrollment => [ 'http://purl.imsglobal.org/vocab/lis/v2/membership#Instructor' ].freeze,
      DesignerEnrollment => [ 'http://purl.imsglobal.org/vocab/lis/v2/membership#ContentDeveloper' ].freeze,
      ObserverEnrollment => [ 'http://purl.imsglobal.org/vocab/lis/v2/membership#Mentor' ].freeze,
      StudentViewEnrollment => [ 'http://purl.imsglobal.org/vocab/lis/v2/membership#Learner' ].freeze,
      :group_member => [ 'http://purl.imsglobal.org/vocab/lis/v2/membership#Member' ].freeze,
      :group_leader => [
        'http://purl.imsglobal.org/vocab/lis/v2/membership#Member',
        'http://purl.imsglobal.org/vocab/lis/v2/membership#Manager'
      ].freeze
    }.freeze

    # Inversion of LIS_V2_LTI_ADVANTAGE_ROLE_MAP, i.e.:
    #
    #   {
    #     '<lis-url>' => [<enrollment-class>, <logical-sys-or-insitution-role-name-string>, <enrollment-class>],
    #     '<lis-url>' => [<group-membership-type-symbol>, <group-membership-type-symbol>],
    #     ...
    #   }
    #
    # (Extra copy at the end is to undo the default value ([]))
    INVERTED_LIS_V2_LTI_ADVANTAGE_ROLE_MAP = LIS_V2_LTI_ADVANTAGE_ROLE_MAP.each_with_object(Hash.new([])) do |(key,values), memo|
      values.each { |value| memo[value] += [key] }
    end.reverse_merge({}).freeze

    LIS_V2_LTI_ADVANTAGE_ROLE_NONE = 'http://purl.imsglobal.org/vocab/lis/v2/system/person#None'.freeze

    def initialize(context, root_account, user, tool = nil)
      @context = context
      @root_account = root_account
      @user = user
      @tool = tool
    end

    def account
      @account ||=
          case @context
            when Account
              @context
            when Course
              @context.account
            else
              @root_account
          end
    end

    def enrollments_to_lis_roles(enrollments)
      enrollments.map { |enrollment| Lti::LtiUserCreator::ENROLLMENT_MAP[enrollment.class] }.uniq
    end

    def all_roles(version = 'lis1')
      case version
      when 'lis2'
        role_map = LIS_V2_ROLE_MAP
        role_none = LIS_V2_ROLE_NONE
      when 'lti1_3'
        role_map = LIS_V2_LTI_ADVANTAGE_ROLE_MAP
        role_none = LIS_V2_LTI_ADVANTAGE_ROLE_NONE
      else
        role_map = LIS_ROLE_MAP
        role_none = LtiOutbound::LTIRoles::System::NONE
      end

      if @user
        context_roles = course_enrollments.each_with_object(Set.new) { |role, set| set.add([*role_map[role.class]].join(",")) }

        institution_roles = @user.roles(@root_account, true).flat_map { |role| role_map[role] }
        if Account.site_admin.account_users_for(@user).present?
          institution_roles.push(*role_map['siteadmin'])
        end
        (context_roles + institution_roles).to_a.compact.uniq.sort.join(',')
      else
        role_none
      end
    end

    def course_enrollments
      return [] unless @context.is_a?(Course) && @user
      @current_course_enrollments ||= @context.current_enrollments.where(user_id: @user.id)
    end

    def course_sections
      return [] unless @context.is_a?(Course) && @user
      @current_course_sections ||= @context.course_sections.where(id: course_enrollments.map(&:course_section_id)).select("id, sis_source_id")
    end

    def account_enrollments
      unless @current_account_enrollments
        @current_account_enrollments = []
        if @user && @context.respond_to?(:account_chain) && !@context.account_chain.empty?
          @current_account_enrollments = AccountUser.active.where(user_id: @user, account_id: @context.account_chain).shard(@context.shard)
        end
      end
      @current_account_enrollments
    end

    def current_lis_roles
      enrollments = course_enrollments + account_enrollments
      enrollments.size > 0 ? enrollments_to_lis_roles(enrollments).join(',') : LtiOutbound::LTIRoles::System::NONE
    end

    def concluded_course_enrollments
      @concluded_course_enrollments ||=
          @context.is_a?(Course) && @user ? @user.enrollments.concluded.where(course_id: @context.id).shard(@context.shard) : []
    end

    def concluded_lis_roles
      concluded_course_enrollments.size > 0 ? enrollments_to_lis_roles(concluded_course_enrollments).join(',') : LtiOutbound::LTIRoles::System::NONE
    end

    def granted_permissions(permissions_to_check)
      permissions_to_check.select{|p| @context.grants_right?(@user, p.to_sym) }.join(",")
    end

    def current_canvas_roles
      roles = (course_enrollments + account_enrollments).map(&:role).map(&:name).uniq
      roles = roles.map{|role| role == "AccountAdmin" ? "Account Admin" : role} # to maintain backwards compatibility
      roles.join(',')
    end

    def current_canvas_roles_lis_v2(version = 'lis2')
      roles = (course_enrollments + account_enrollments).map(&:class).uniq
      role_map = version == 'lti1_3' ? LIS_V2_LTI_ADVANTAGE_ROLE_MAP : LIS_V2_ROLE_MAP
      roles.map { |r| role_map[r] }.join(',')
    end

    def enrollment_state
      enrollments = @user ? @context.enrollments.where(user_id: @user.id).preload(:enrollment_state) : []
      return '' if enrollments.size == 0
      enrollments.any? { |membership| membership.state_based_on_date == :active } ? LtiOutbound::LTIUser::ACTIVE_STATE : LtiOutbound::LTIUser::INACTIVE_STATE
    end

    def previous_lti_context_ids
      previous_course_ids_and_context_ids.map(&:last).compact.join(',')
    end

    def recursively_fetch_previous_lti_context_ids
      recursively_fetch_previous_course_ids_and_context_ids.map(&:last).compact.join(',')
    end

    def previous_course_ids
      previous_course_ids_and_context_ids.map(&:first).sort.join(',')
    end

    def section_ids
      course_enrollments.map(&:course_section_id).uniq.sort.join(',')
    end

    def section_restricted
      @context.is_a?(Course) && @user && @context.visibility_limited_to_course_sections?(@user)
    end

    def section_sis_ids
      course_sections.map(&:sis_source_id).compact.uniq.sort.join(',')
    end

    def sis_email
      sis_ps = SisPseudonym.for(@user, @context, type: :trusted, require_sis: true)
      sis_ps.sis_communication_channel&.path || sis_ps.communication_channels.order(:position).active.first&.path if sis_ps
    end

    def email
      # we are using sis_email for lti2 tools, or if the 'prefer_sis_email' extension is set for LTI 1
      e = if !lti1? || (@tool&.extension_setting(nil, :prefer_sis_email)&.downcase ||
            @tool&.extension_setting(:tool_configuration, :prefer_sis_email)&.downcase) == "true"
            sis_email
          end
      e || @user.email
    end

    private

    def lti1?
      @tool&.respond_to?(:extension_setting)
    end

    def previous_course_ids_and_context_ids
      return [] unless @context.is_a?(Course)
      @previous_ids ||= Course.where(
        "EXISTS (?)", ContentMigration.where(context_id: @context.id, workflow_state: :imported).where("content_migrations.source_course_id = courses.id")
      ).pluck(:id, :lti_context_id)
    end

    def recursively_fetch_previous_course_ids_and_context_ids
      return [] unless @context.is_a?(Course)

      # now find all parents for locked folders
      last_migration_id = @context.content_migrations.where(workflow_state: :imported).order(:id => :desc).limit(1).pluck(:id).first
      return [] unless last_migration_id

      # we can cache on the last migration because even if copies are done elsewhere they won't affect anything
      # until a new copy is made to _this_ course
      Rails.cache.fetch(["recursive_copied_course_lti_ids", @context.global_id, last_migration_id].cache_key) do
        Course.where(
          "EXISTS (?)", ContentMigration.where(workflow_state: :imported).where("context_id = ? OR context_id IN (
              WITH RECURSIVE t AS (
                SELECT context_id, source_course_id FROM #{ContentMigration.quoted_table_name} WHERE context_id = ?
                UNION
                SELECT content_migrations.context_id, content_migrations.source_course_id FROM #{ContentMigration.quoted_table_name} INNER JOIN t ON content_migrations.context_id=t.source_course_id
              )
              SELECT DISTINCT context_id FROM t
            )", @context.id, @context.id).where("content_migrations.source_course_id = courses.id")
        ).pluck(:id, :lti_context_id)
      end
    end
  end
end