canvas-lms/app/controllers/context_module_items_api_controller.rb

#
# Copyright (C) 2013 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/>.
#

# @API Modules
# @subtopic Module Items
#
# @object ModuleItem
#     {
#       // the unique identifier for the module item
#       "id": 768,
#
#       // the id of the Module this item appears in
#       "module_id": 123,
#
#       // the position of this item in the module (1-based)
#       "position": 1,
#
#       // the title of this item
#       "title": "Square Roots: Irrational numbers or boxy vegetables?",
#
#       // 0-based indent level; module items may be indented to show a hierarchy
#       "indent": 0,
#
#       // the type of object referred to
#       // one of "File", "Page", "Discussion", "Assignment", "Quiz", "SubHeader",
#       // "ExternalUrl", "ExternalTool"
#       "type": "Assignment",
#
#       // the id of the object referred to
#       // applies to "File", "Discussion", "Assignment", "Quiz", "ExternalTool" types
#       "content_id": 1337,
#
#       // link to the item in Canvas
#       "html_url": "https://canvas.example.edu/courses/222/modules/items/768",
#
#       // (Optional) link to the Canvas API object, if applicable
#       "url": "https://canvas.example.edu/api/v1/courses/222/assignments/987",
#
#       // (only for 'Page' type) unique locator for the linked wiki page
#       "page_url": "my-page-title",
#
#       // (only for 'ExternalUrl' and 'ExternalTool' types) external url that the item points to
#       "external_url": "https://www.example.com/externalurl",
#
#       // (only for 'ExternalTool' type) whether the external tool opens in a new tab
#       "new_tab": false,
#
#       // Completion requirement for this module item
#       "completion_requirement": {
#         // one of "must_view", "must_submit", "must_contribute", "min_score"
#         "type": "min_score",
#
#         // minimum score required to complete (only present when type == 'min_score')
#         "min_score": 10,
#
#         // whether the calling user has met this requirement
#         // (Optional; present only if the caller is a student)
#         "completed": true
#       },
#
#       // (Present only if requested through include[]=content_details)
#       // If applicable, returns additional details specific to the associated object
#       "content_details": {
#         "points_possible": 20,
#         "due_at": "2012-12-31T06:00:00-06:00",
#         "unlock_at": "2012-12-31T06:00:00-06:00",
#         "lock_at": "2012-12-31T06:00:00-06:00"
#       }
#     }
#
#
# @object ModuleItemSequence
#     {
#       // an array containing one hash for each appearence of the asset in the module sequence
#       // (up to 10 total)
#       "items": [
#         {
#           // the ModuleItem for the previous asset in the sequence, if present
#           // this is the previous asset in the module, or the last asset in the previous module,
#           // or null if this is the first module item in the course sequence
#           "prev": null,
#
#           // the ModuleItem for the requested asset
#           "current": {
#             "id": 768,
#             "module_id": 123,
#             "title": "A lonely page",
#             "type": "Page"
#             // ...
#           },
#
#           // the ModuleItem for the next asset in the sequence, if present
#           // this is the next asset in the module, or the first asset in the next module,
#           // or null if this is the last module item in the course sequence
#           "next": {
#             "id": 769,
#             "module_id": 127,
#             "title": "Project 1",
#             "type": "Assignment"
#             // ...
#           }
#         }
#       ],
#
#       // an array containing each Module referenced above
#       "modules": [
#         {
#           "id": 123,
#           "name": "Module A"
#           // ...
#         },
#         {
#           "id": 127,
#           "name": "Module B"
#           // ...
#         }
#       ]
#     }
class ContextModuleItemsApiController < ApplicationController
  before_filter :require_context
  include Api::V1::ContextModule

  # @API List module items
  #
  # List the items in a module
  #
  # @argument include[] [String, "content_details"]
  #   If included, will return additional details specific to the content
  #   associated with each item. Refer to the {api:Modules:Module%20Item Module
  #   Item specification} for more details.
  #
  # @argument search_term [Optional, String]
  #   The partial title of the items to match and return.
  #
  # @example_request
  #     curl -H 'Authorization: Bearer <token>' \
  #          https://<canvas>/api/v1/courses/222/modules/123/items
  #
  # @returns [ModuleItem]
  def index
    if authorized_action(@context, @current_user, :read)
      mod = @context.modules_visible_to(@current_user).find(params[:module_id])
      ContextModule.send(:preload_associations, mod, {:content_tags => :content})
      route = polymorphic_url([:api_v1, @context, mod, :items])
      scope = mod.content_tags_visible_to(@current_user)
      scope = ContentTag.search_by_attribute(scope, :title, params[:search_term])
      items = Api.paginate(scope, self, route)
      prog = @context.grants_right?(@current_user, session, :participate_as_student) ? mod.evaluate_for(@current_user) : nil
      render :json => items.map { |item| module_item_json(item, @current_user, session, mod, prog, Array(params[:include])) }
    end
  end

  # @API Show module item
  #
  # Get information about a single module item
  #
  # @argument include[] [String, "content_details"]
  #   If included, will return additional details specific to the content
  #   associated with this item. Refer to the {api:Modules:Module%20Item Module
  #   Item specification} for more details.
  #
  # @example_request
  #     curl -H 'Authorization: Bearer <token>' \
  #          https://<canvas>/api/v1/courses/222/modules/123/items/768
  #
  # @returns ModuleItem
  def show
    if authorized_action(@context, @current_user, :read)
      mod = @context.modules_visible_to(@current_user).find(params[:module_id])
      item = mod.content_tags_visible_to(@current_user).find(params[:id])
      prog = @context.grants_right?(@current_user, session, :participate_as_student) ? mod.evaluate_for(@current_user) : nil
      render :json => module_item_json(item, @current_user, session, mod, prog, Array(params[:include]))
    end
  end

  # Mark an external URL content tag read for purposes of module progression,
  # then redirect to the URL (vs. render in an iframe like content_tag_redirect).
  # Not documented directly; part of an opaque URL returned by above endpoints.
  def redirect
    if authorized_action(@context, @current_user, :read)
      @tag = @context.context_module_tags.not_deleted.find(params[:id])
      if !(@tag.unpublished? || @tag.context_module.unpublished?) || authorized_action(@tag.context_module, @current_user, :update)
        if @tag.content_type == 'ExternalUrl'
          @tag.context_module_action(@current_user, :read)
          redirect_to @tag.url
        else
          return render(:status => 400, :json => { :message => "incorrect module item type" })
        end
      end
    end
  end

  # @API Create a module item
  #
  # Create and return a new module item
  #
  # @argument module_item[title] [Optional, String]
  #   The name of the module item and associated content
  #
  # @argument module_item[type] [String, "File"|"Page"|"Discussion"|"Assignment"|"Quiz"|"SubHeader"|"ExternalUrl"|"ExternalTool"]
  #   The type of content linked to the item
  #
  # @argument module_item[content_id] [String]
  #   The id of the content to link to the module item. Required, except for
  #   'ExternalUrl', 'Page', and 'SubHeader' types.
  #
  # @argument module_item[position] [Optional, Integer]
  #   The position of this item in the module (1-based).
  #
  # @argument module_item[indent] [Optional, Integer]
  #   0-based indent level; module items may be indented to show a hierarchy
  #
  # @argument module_item[page_url] [String]
  #   Suffix for the linked wiki page (e.g. 'front-page'). Required for 'Page'
  #   type.
  #
  # @argument module_item[external_url] [String]
  #   External url that the item points to. [Required for 'ExternalUrl' and
  #   'ExternalTool' types.
  #
  # @argument module_item[new_tab] [Optional, Boolean]
  #   Whether the external tool opens in a new tab. Only applies to
  #   'ExternalTool' type.
  #
  # @argument module_item[completion_requirement][type] [Optional, String, "must_view"|"must_contribute"|"must_submit"]
  #   Completion requirement for this module item.
  #   "must_view": Applies to all item types
  #   "must_contribute": Only applies to "Assignment", "Discussion", and "Page" types
  #   "must_submit", "min_score": Only apply to "Assignment" and "Quiz" types
  #   Inapplicable types will be ignored
  #
  # @argument module_item[completion_requirement][min_score] [Integer]
  #   Minimum score required to complete. Required for completion_requirement
  #   type 'min_score'.
  #
  # @example_request
  #
  #     curl https://<canvas>/api/v1/courses/<course_id>/modules/<module_id>/items \
  #       -X POST \
  #       -H 'Authorization: Bearer <token>' \
  #       -d 'module_item[title]=module item' \
  #       -d 'module_item[type]=ExternalTool' \
  #       -d 'module_item[content_id]=10' \
  #       -d 'module_item[position]=2' \
  #       -d 'module_item[indent]=1' \
  #       -d 'module_item[new_tab]=true'
  #
  # @returns ModuleItem
  def create
    @module = @context.context_modules.not_deleted.find(params[:module_id])
    if authorized_action(@module, @current_user, :update)
      return render :json => {:message => "missing module item parameter"}, :status => :bad_request unless params[:module_item]

      item_params = params[:module_item].slice(:title, :type, :indent, :new_tab)
      item_params[:id] = params[:module_item][:content_id]
      if ['Page', 'WikiPage'].include?(item_params[:type])
        if page_url = params[:module_item][:page_url]
          if wiki_page = @context.wiki.wiki_pages.find_by_url(page_url)
            item_params[:id] = wiki_page.id
          else
            return render :json => {:message => "invalid page_url parameter"}, :status => :bad_request
          end
        else
          return render :json => {:message => "missing page_url parameter"}, :status => :bad_request
        end
      end

      item_params[:url] = params[:module_item][:external_url]

      if (@tag = @module.add_item(item_params)) && set_position && set_completion_requirement
        if @domain_root_account.enable_draft?
          @tag.workflow_state = 'unpublished'
          @tag.save
        end
        @module.touch
        render :json => module_item_json(@tag, @current_user, session, @module, nil)
      elsif @tag
        render :json => @tag.errors.to_json, :status => :bad_request
      else
        render :status => 400, :json => { :message => t(:invalid_content, "Could not find content") }
      end
    end
  end

  # @API Update a module item
  #
  # Update and return an existing module item
  #
  # @argument module_item[title] [Optional, String]
  #   The name of the module item
  #
  # @argument module_item[position] [Optional, Integer]
  #   The position of this item in the module (1-based)
  #
  # @argument module_item[indent] [Optional, Integer]
  #   0-based indent level; module items may be indented to show a hierarchy
  #
  # @argument module_item[external_url] [Optional, String]
  #   External url that the item points to. Only applies to 'ExternalUrl' type.
  #
  # @argument module_item[new_tab] [Optional, Boolean]
  #   Whether the external tool opens in a new tab. Only applies to
  #   'ExternalTool' type.
  #
  # @argument module_item[completion_requirement][type] [Optional, "must_view"|"must_contribute"|"must_submit"]
  #   Completion requirement for this module item.
  #   "must_view": Applies to all item types
  #   "must_contribute": Only applies to "Assignment", "Discussion", and "Page" types
  #   "must_submit", "min_score": Only apply to "Assignment" and "Quiz" types
  #   Inapplicable types will be ignored
  #
  # @argument module_item[completion_requirement][min_score] [Integer]
  #   Minimum score required to complete, Required for completion_requirement
  #   type 'min_score'.
  #
  # @argument module_item[published] [Optional, Boolean]
  #   Whether the module item is published and visible to students.
  #
  # @argument module_item[module_id] [Optional, String]
  #   Move this item to another module by specifying the target module id here.
  #   The target module must be in the same course.
  #
  # @example_request
  #
  #     curl https://<canvas>/api/v1/courses/<course_id>/modules/<module_id>/items/<item_id> \
  #       -X PUT \
  #       -H 'Authorization: Bearer <token>' \
  #       -d 'module_item[content_id]=10' \
  #       -d 'module_item[position]=2' \
  #       -d 'module_item[indent]=1' \
  #       -d 'module_item[new_tab]=true'
  #
  # @returns ModuleItem
  def update
    @tag = @context.context_module_tags.not_deleted.find(params[:id])
    if authorized_action(@tag.context_module, @current_user, :update)
      return render :json => {:message => "missing module item parameter"}, :status => :bad_request unless params[:module_item]

      @tag.title = params[:module_item][:title] if params[:module_item][:title]
      @tag.url = params[:module_item][:external_url] if %w(ExternalUrl ContextExternalTool).include?(@tag.content_type) && params[:module_item][:external_url]
      @tag.indent = params[:module_item][:indent] if params[:module_item][:indent]
      @tag.new_tab = value_to_boolean(params[:module_item][:new_tab]) if params[:module_item][:new_tab]
      if target_module_id = params[:module_item][:module_id]
        target_module = @context.context_modules.find_by_id(target_module_id)
        return render :json => {:message => "invalid module_id"}, :status => :bad_request unless target_module
        old_module = @context.context_modules.find(@tag.context_module_id)
        @tag.context_module = target_module
        if req_index = old_module.completion_requirements.find_index { |req| req[:id] == @tag.id }
          old_module.completion_requirements_will_change!
          req = old_module.completion_requirements.delete_at(req_index)
          old_module.save!
          params[:module_item][:completion_requirement] = req
        else
          ContentTag.touch_context_modules([old_module.id, target_module_id])
        end
      end

      if params[:module_item].has_key?(:published)
        if value_to_boolean(params[:module_item][:published])
          @tag.publish
        else
          @tag.unpublish
        end
        @tag.save
        @tag.update_asset_workflow_state!
        @tag.context_module.save
      end

      if @tag.save && set_position && set_completion_requirement
        @tag.update_asset_name! if params[:module_item][:title]
        render :json => module_item_json(@tag, @current_user, session, @tag.context_module, nil)
      else
        render :json => @tag.errors.to_json, :status => :bad_request
      end
    end
  end

  # @API Delete module item
  #
  # Delete a module item
  #
  # @example_request
  #
  #     curl https://<canvas>/api/v1/courses/<course_id>/modules/<module_id>/items/<item_id> \
  #       -X Delete \
  #       -H 'Authorization: Bearer <token>'
  #
  # @returns ModuleItem
  def destroy
    @tag = @context.context_module_tags.not_deleted.find(params[:id])
    if authorized_action(@tag.context_module, @current_user, :update)
      @module = @tag.context_module
      @tag.destroy
      @module.touch
      render :json => module_item_json(@tag, @current_user, session, @module, nil)
    end
  end

  MAX_SEQUENCES = 10

  # @API Get module item sequence
  #
  # Given an asset in a course, find the ModuleItem it belongs to, and also the previous and next Module Items
  # in the course sequence.
  #
  # @argument asset_type [String, "ModuleItem"|"File"|"Page"|"Discussion"|"Assignment"|"Quiz"|"ExternalTool"]
  #   The type of asset to find module sequence information for. Use the ModuleItem if it is known
  #   (e.g., the user navigated from a module item), since this will avoid ambiguity if the asset
  #   appears more than once in the module sequence.
  #
  # @argument asset_id [Integer]
  #   The id of the asset (or the url in the case of a Page)
  #
  # @example_request
  #
  #     curl https://<canvas>/api/v1/courses/<course_id>/module_item_sequence?asset_type=Assignment&asset_id=123 \
  #       -H 'Authorization: Bearer <token>'
  #
  # @returns ModuleItemSequence
  def item_sequence
    if authorized_action(@context, @current_user, :read)
      asset_type = Api.api_type_to_canvas_name(params[:asset_type])
      return render :json => { :message => 'invalid asset_type'}, :status => :bad_request unless asset_type
      asset_id = params[:asset_id]
      return render :json => { :message => 'missing asset_id' }, :status => :bad_request unless asset_id

      # assemble a sequence of content tags in the course
      tags = @context.module_items_visible_to(@current_user).
          select('content_tags.*, context_modules.position AS module_position').
          reject { |item| item.content_type == 'ContextModuleSubHeader' }.
          sort_by { |item| [item.module_position.to_i, item.position] }

      # find content tags to include
      tag_indices = []
      if asset_type == 'ContentTag'
        tag_ix = tags.each_index.detect { |ix| tags[ix].id == asset_id.to_i }
        tag_indices << tag_ix if tag_ix
      else
        # map wiki page url to id
        if asset_type == 'WikiPage'
          page = @context.wiki.wiki_pages.find_by_url(asset_id)
          asset_id = page.id if page
        else
          asset_id = asset_id.to_i
        end

        # find the associated assignment id, if applicable
        if (asset_type == 'DiscussionTopic' || asset_type == 'Quiz')
          asset = @context.send(asset_type.tableize).find_by_id(asset_id.to_i)
          associated_assignment_id = asset.assignment_id if asset
        end

        # find up to MAX_SEQUENCES tags containing the object (or its associated assignment)
        tags.each_index do |ix|
          if (tags[ix].content_type == asset_type && tags[ix].content_id == asset_id) ||
             (associated_assignment_id && tags[ix].content_type == 'Assignment' && tags[ix].content_id == associated_assignment_id)
            tag_indices << ix
            break if tag_indices.length == MAX_SEQUENCES
          end
        end
      end

      # render the result
      module_ids = Set.new
      result = { :items => [] }
      tag_indices.each do |ix|
        hash = { :current => module_item_json(tags[ix], @current_user, session), :prev => nil, :next => nil }
        module_ids << tags[ix].context_module_id
        if ix > 0
          hash[:prev] = module_item_json(tags[ix - 1], @current_user, session)
          module_ids << tags[ix - 1].context_module_id
        end
        if ix < tags.size - 1
          hash[:next] = module_item_json(tags[ix + 1], @current_user, session)
          module_ids << tags[ix + 1].context_module_id
        end
        result[:items] << hash
      end
      modules = @context.context_modules.find_all_by_id(module_ids.to_a)
      result[:modules] = modules.map { |mod| module_json(mod, @current_user, session) }

      render :json => result
    end
  end

  def set_position
    return true unless @tag && params[:module_item][:position]

    @tag.reload
    if @tag.insert_at_position(params[:module_item][:position], @tag.context_module.content_tags.not_deleted)
      # see ContextModulesController#reorder_items
      @tag.touch_context_module
      ContentTag.update_could_be_locked(@tag.context_module.content_tags)
      @context.touch

      @tag.reload
      return true
    else
      @tag.errors.add(:position, t(:invalid_position, "Invalid position"))
      return false
    end
  end
  protected :set_position

  def set_completion_requirement
    return true unless @tag && params[:module_item][:completion_requirement]

    reqs = {}
    @module ||= @tag.context_module
    @module.completion_requirements.each{|i| reqs[i[:id]] = i }

    if params[:module_item][:completion_requirement].blank?
      reqs[@tag.id] = {}
    elsif ["must_view", "must_submit", "must_contribute", "min_score"].include?(params[:module_item][:completion_requirement][:type])
      reqs[@tag.id] = params[:module_item][:completion_requirement].with_indifferent_access
    else
      @tag.errors.add(:completion_requirement, t(:invalid_requirement_type, "Invalid completion requirement type"))
      return false
    end

    @module.completion_requirements = reqs
    @module.save
  end
  protected :set_completion_requirement
end