CSC/ECE 517 Spring 2013/FINAL PROJECT E736 UNDO DELIVERABLE

E736. Undo Functionality for Expertiza

• Contacts: Ed Gehringer (efg@ncsu.edu) and Andrew Kofink (ajkofink@ncsu.edu)
• Design Document
• Project Description Doc

Team Members

• Chun Sing Tsui (ctsui@ncsu.edu)
• Kenny Yarboro (kbyarbor@ncsu.edu)
• Meng Cao (mcao2@ncsu.edu)
• Travis Folsom (twfolsom@ncsu.edu)

Project Deliverables

Screencast Video Overview

A video overview of the project was created via Screencast-O-Matic and can be found here.

Overview of Undo Functionality

• Undo allows the user to undo and redo their most recent actions for any items that offer the undo functionality.
• The undo of file submissions was not required; it is not implemented in this project.
• If an undo is attempted on an item already modified by another user, a message is displayed stating why undo cannot be performed. Otherwise, the user is able to undo any changes to an item with the undo functionality.
• When multiple actions are performed in one step, the undo functionality groups all of the changes together for the purposes of restoring all items affected by the action previously performed.

List of Items Now Supported by Undo Functionality

• Add Signup Sheet
  • Delete Topic
  • Edit Topic
  • New Topic
• Assignments
  • Add/Remove Participants
  • Inherit Participants from Course
  • Copy Participants to Course
  • Copy
  • Create
  • Delete
  • Edit
  • Add/Remove/Modify questionnaires and their weight and notification limit
• Courses
  • Add Participants
  • Copy
  • Create
  • Delete
  • Edit
  • Toggle Private/Public
• Import
  • Import Participants
  • Import Teams
  • Import Users
• Student Actions
  • Create Team
  • Edit Team Name
  • Leave Team
  • Submit Hyperlink
• Questions
  • Copy
  • Create
  • Delete
  • Edit
• Questionnaires
  • Copy
  • Create
  • Delete
  • Edit
• Teams
  • Add
  • Create (Manual)
  • Create (Random)
  • Delete
  • Delete All Teams
  • Edit

Redo Functionality

In addition to the Undo functionality being added, the ability to Redo an undone action is also implemented. Whenever an Undo is performed, the user is given an option to Redo the action that was undone. Whenever a Redo is performed, the user is given an option to Undo the action again.

Design Patterns and Designs

• DRY
  • "Don't Repeat Yourself" practice was followed.
  • The app/controllers/application_controller.rb file contains all of the Undo functionality code for Expertiza. All other controllers are able to call the necessary undo-related methods to enable the Undo functionality.

Framework Leveraged & Enhanced

• Paper Trail(https://github.com/airblade/paper_trail)
  • Paper Trail allows for tracking changes to model data.
    • Good for auditing or versioning.
  • Offers many functionalities including:
    • • Viewing a model at any stage in its lifecycle.
      • Reverting a model to any version.
      • Undeleting items after they have been destroyed.
  • Compatible with Rails-2.3.15, which is the version Expertiza uses.
  • There is a Railscast showing how to implement the undo feature with Paper Trail.
  • Ranked as the most popular framework for Active Record versioning feature in here
• Enhancement
  • Paper Trail only supported undo of the most recent action and did not restore associations.
  • Paper Trail customized to add support for restoring associations within the Expertiza system.
    • Database transactions paired with timestamps and user ids to group them together.

Classes Modified

• apps/
  • controllers/
    • application_controller.rb
    • assignment_controller.rb
    • course_controller.rb
    • import_file_controller.rb
    • participants_controller.rb
    • sign_up_sheet_controller.rb
    • student_team_controller.rb
    • team_controller.rb
    • teams_users_controller.rb
    • versions_controller.rb
  • models/
    • assignment_participant.rb
    • assignment.rb
    • questionnaire.rb
    • course.rb
    • participant.rb
    • sign_up_topic.rb
    • ta_mapping.rb
    • team_node.rb
    • teams_user.rb
• db/
  • migrate/
    • 000_create_versions.rb
    • 20130418214537_update_site_controllers_for_versions.rb
    • 20130418215246_update_controller_actions_for_versions_revert.rb

Unit & Functional Tests

The implementation of the Undo functionality did not afford any testing opportunities applicable to unit or functional tests.

Bug Fixes & Other Improvements

The following bugs were found within Expertiza and fixed:

• ApplicationController enhanced to rescue from ActiveRecord::RecordNotFound errors and redirect to tree display.
• Copy of Assignment opened Edit page for the original Assignment and now correctly opens the Edit page for the copy of the assignment.

The following general improvements were made:

• Explicitly declared the has_one association between each object and its tree node to eliminate the manual deletion of a related tree node with the object.
• Edited the Copy of Course flash message to be more clear that the copy had already been created and to resolve a misspelling.

Problem Areas with Expertiza

There were some areas of functionality within Expertiza that did not work. There were some cases in which the undo functionality could not be added due to the inherent problems. These problem areas were:

• Assigning surveys in an assignment.
• Dates in assignments do not show up when the assignment is edited.
• Unable to assign random reviewers.
• Unable to edit advice for questions in questionnaire.
• Unable to remove participants from a course.
• Unable to inherit team from a course

Future Recommendations

• Add integration tests.
• Add undo functionality to other areas of Expertiza (especially student actions such as review responses)
• Determine appropriate methodology for cleaning up Versions table.

Template to Implement Undo Functionality

• Install paper_trail gem. Please follow the steps listed on its official webpage .
• Add has_paper_trail to the model you want to have undo functionality

class Foo < ActiveRecord::Base
    has_paper_trail
    ...
end

• Call undo_link method in the corresponding controller. The argument is a string, which you want to show along with the undo link in flash[:note]. The following is code snippet shows how the undo functionality is implemented for the delete method of FoosController

class FoosController < ApplicationController
    def delete
        @foo = Foo.find(params[:id])
        @foo.destroy
        undo_link("Foo \"#{@foo.name}\" has been deleted successfully. ")
        redirect_to :back
    end
end