CSC/ECE 517 Fall 2015/oss E1559 rrz

E1559: Refactoring JoinTeamRequestsController and InvitationController classes

This page gives a breif description on the expertiza based oss project that aimed at refactoring JoinTeamRequestController.rb and InvitationController.rb classes so that they follow the DRY principle and Ruby on Rails coding practices.

Code Refactoring

Code refactoring is process of changing the code to make it more maintainable, without changing the functionality of the code. Some of the reasons for performing refactoring are:

• To remove duplicate code.
• To make the code more maintainable.
• To divide functionality of the class

Introduction to Expertiza

Expertiza is a web application where students can submit and review learning objects like code, writings, etc. It gives scope for creation of reusable learning objects. Students submit assignments, which can than graded through peer reviews. The Expertiza project is supported by the National Science Foundation.

Problem Statement

Classes involved

JoinTeamRequestsController.rb and InvitationController.rb

What the controller does

InvitationController.rb is used by a user to invite other users to join his/her team. It performs validation before creating a request. Now, invited user can accept or reject the request. JoinTeamRequestsController.rb is used when user decides to join a team.

What's wrong with the code

The InvitationController.rb is doing the required task but it is difficult to understand the code, hence it becomes difficult to maintain the code. And the functions in the accept and create method can be broken down into separate methods. In JoinTeamRequestController.rb has duplicate code in various methods which can be removed by creating a seperate method for this common code.

What needs to be done

InvitationController.rb

• Rename to Invitations_Controller.rb, as is not in accordance with current naming convention.
• Add comments explaining what each method does, and comments on how important variables are used as currently there are no comments.
• Refactor create and accept methods. Shorten and clarify them by adding private methods, as create and accept methods currently have a lot of code.
• Change the find_by_sql call(s) to Rails (Active Record) statements.
• Make sure that it can be used by a user with a TA or instructor account, if they are participating in this assignment.
• Change grammatically wrong or awkward flash messages.

JoinTeamRequestsController.rb

• Add comments to the code.
• Remove duplicate code.
• Update create and accept method to share code.
• Decline and destroy method should check for successful operation before returning.
• Change grammatically wrong or awkward flash messages.

Implementation

Renamed invitation_controller.rb to invitations_controller.rb

The controller renaming had to be incorporated in different files of the project. The table contain the file names along with the lines before and after the changes.

File Name	Line no.	Before	After
config/routes.rb	160	resources :invitation do	resources :invitations do
app/views/student_teams/view.html.erb	151	{:controller => 'invitation', :action => 'cancel', :inv_id => inv.id, :student_id => @student.id} %>	{:controller => 'invitations', :action => 'cancel', :inv_id => inv.id, :student_id => @student.id} %>
app/views/student_teams/view.html.erb	193	{:controller => 'invitation', :action => 'accept', :inv_id => inv.id, :student_id => @student.id, :team_id => @team_id},	{:controller => 'invitations', :action => 'accept', :inv_id => inv.id, :student_id => @student.id, :team_id => @team_id},
app/views/student_teams/view.html.erb	198	{:controller => 'invitation', :action => 'decline', :inv_id => inv.id, :student_id => @student.id} %>	{:controller => 'invitations', :action => 'decline', :inv_id => inv.id, :student_id => @student.id} %>
app/views/student_teams/view.html.erb	217	<%= form_tag :controller => 'invitation', :action => 'create' do %>	<%= form_tag :controller => 'invitations', :action => 'create' do %>

JoinTeamRequestController.rb removed duplicate code

Before	After
def index @join_team_requests = JoinTeamRequest.all respond_to do |format| format.html # index.html.erb format.xml { render :xml => @join_team_requests } end	def index @join_team_request = JoinTeamRequest.all render_request # index.html.erb end
def show # searches the join team requests for a particular id @join_team_request = JoinTeamRequest.find(params[:id]) respond_to do |format| format.html # show.html.erb format.xml { render :xml => @join_team_request } end end def new # create a new join team request entry instance @join_team_request = JoinTeamRequest.new respond_to do |format| format.html # new.html.erb format.xml { render :xml => @join_team_request } end end	private def render_request respond_to do |format| format.html format.xml { render :xml => @join_team_request } end end def show # searches the join team requests for a particular id @join_team_request = JoinTeamRequest.find(params[:id]) render_request # show.html.erb end def new # create a new join team request entry instance @join_team_request = JoinTeamRequest.new render_request # new.html.erb end