CSC/ECE 517 Spring 2025 - E2511. Reimplement participants controller.rb

About Expertiza

Expertiza is an open source project based on Ruby on Rails framework. Expertiza allows the instructor to create new assignments and customize new or existing assignments. It also allows the instructor to create a list of topics the students can sign up for. Students can form teams in Expertiza to work on various projects and assignments. Students can also peer review other students' submissions. Expertiza supports submission across various document types, including the URLs and wiki pages.

Introduction

This project aims to reimplement the participants_controller.rb and participants_helper.rb in the new Expertiza system. The participants_controller.rb manages participants within assignments, and this reimplementation focuses on streamlining its methods, eliminating redundancy, and enhancing code readability and maintainability.

Requirements

• Implement participants_controller.rb Methods: Fully implement each controller method with the same functionality as the current controller.
• Import from participants_helper.rb: Integrate relevant helper methods to streamline functionality and remove redundancy.
• API Creation: Expose API endpoints for all necessary methods to enable seamless access and integration from the frontend. Ensure that each endpoint follows best practices for RESTful API design, including proper error handling and secure data access.
• Testing with rswag: Create test cases for all methods, focusing on edge cases, and generate rswag documentation.
• Swagger UI Video Documentation: Record a video walkthrough of API endpoints in Swagger UI, showcasing each method’s functionality.

Tasks to be Completed

• Implement participants_controller.rb Methods: Develop each method with the same functionality as the existing controller.
• Refactor and Integrate Helper Methods: Import relevant methods from participants_helper.rb to improve efficiency and eliminate code duplication.
• API Development: Expose RESTful API endpoints for necessary operations, ensuring proper error handling and secure data access.
• Testing with Rswag: Implement comprehensive test cases, including edge cases, and generate Rswag documentation.
• Swagger UI Documentation: Create a video walkthrough demonstrating API endpoints and their functionalities in Swagger UI.
• Make sure to write intuitive test cases for this controller using RSpec

Reimplement participants_controller.rb

participants_controller.rb Methods / API Calls

#	HTTP Method	Endpoint	Method Name	Description
1	GET	/api/v1/participants	index	List all participants
2	POST	/api/v1/participants	create	Create a new participant
3	GET	/api/v1/participants/:id	show	Retrieve a participant by ID
4	PUT	/api/v1/participants/:id	update	Update a participant
5	DELETE	/api/v1/participants/:id	destroy	Delete a participant
6	GET	/api/v1/participants/user/:user_id	user_index	Get participants by user ID
7	GET	/api/v1/participants/assignment/:assignment_id	assignment_index	Get participants by assignment ID
8	POST	/api/v1/participants/:id/:authorization	add	Add a participant with authorization
9	PATCH	/api/v1/participants/:id/:authorization	update_authorization	Update participant authorization

Removed Methods from participants_controller.rb

The following methods were removed as part of the reimplementation:

• action_allowed? – No impact on functionality.
• controller_locale – No impact on functionality.
• inherit – Redundant due to lack of direct relation between Course and Participant.
• bequeath_all – Same reason as above.
• change_handle – `User` model already has `handle`, so it's redundant.
• delete – Replaced by `remove_participant` in assignments_controller.rb.
• view_copyright_grants – Old implementation was incorrect.
• get_user_info – Covered by `belongs_to` relation in the `Participant` model.
• get_signup_topics_for_assignment – Now handled by `sign_up_topics_controller.rb`.

Implementation Summary

Api::V1::ParticipantsController was restructured to:

• Follow RESTful conventions (`index`, `show`, `create`, `update`, `destroy`)
• Add custom endpoints for `user_index`, `assignment_index`, and `update_authorization`
• Leverage strong parameters and `before_action` filters
• Integrate logic from `participants_helper.rb` (like `participant_permissions`)
• Improve error handling using status codes and JSON messages

participants_helper.rb Methods

The ParticipantsHelper module contains utility methods used to assign roles and permissions to a Participant. Compared to the original implementation, this version has been heavily simplified and cleaned up.

Only the following method is included in the reimplementation:

• retrieve_participant_permissions – Returns a hash of permission flags based on the participant’s assigned role.

 This method sets default permissions (submit, review, quiz, mentor) and overrides them based on the role passed in. The supported roles are:
 * reader
 * reviewer
 * submitter
 * mentor

 ```ruby
 def retrieve_participant_permissions(authorization)
   default_permissions = {
     can_submit: true,
     can_review: true,
     can_take_quiz: true,
     can_mentor: false
   }

   permissions_map = {
     'reader' => { can_submit: false },
     'reviewer' => { can_submit: false, can_take_quiz: false },
     'submitter' => { can_review: false, can_take_quiz: false },
     'mentor' => { can_mentor: true }
   }

   default_permissions.merge(permissions_map[authorization])
 end

Role-Based Strategy Pattern

As part of this reimplementation, a Strategy Design Pattern was introduced to streamline role-based permission handling, replacing the large conditional structure previously present in participants_helper.rb.

This pattern allows each role to encapsulate its own permission logic, enabling easier testing, extension, and adherence to SOLID principles.

Structure

The strategy pattern consists of the following components located under the Strategies/roles directory:

• mentor_strategy.rb
• reviewer_strategy.rb
• student_strategy.rb
• teacher_assistant_strategy.rb
• role_strategy.rb – Base module defining required methods
• role_context.rb – Context class that uses strategies dynamically

How it Works

Each role strategy implements the get_permissions method to return a role-specific permission hash, for example:

```ruby

1. Example from MentorStrategy

def get_permissions

 {
   can_submit: false,
   can_review: false,
   can_take_quiz: false,
   can_mentor: true
 }

end

Resources

• Expertiza GitHub Repository
• Rails Routing Guide
• rswag API Documentation Tool

Team Members

• Vansh Dodiya (vkdodiya)
• Brian Huynh (bhhuynh)
• Akhil Adusumilli (aadusum)

Mentor

• Aniruddha Rajnekar