CSC/ECE 517 Fall 2014/oss E1508 MRS

E1508 Refactoring Response Controller

This page provides a description of the Expertiza based OSS project. This project aimed at refactoring the ResponseController.

Introduction to Expertiza

Expertiza is a web application where students can submit and peer-review learning objects (articles, code, web sites, etc). The Expertiza project is supported by the National Science Foundation.<ref>Expertiza</ref><ref>Wiki</ref>

Problem Statement

Classes involved:

response_controller.rb
response.rb

What they do: Allows the user to create and edit responses to questionnaires … such as performing a review, rating a teammate, or giving feedback to a reviewer.

What's wrong with it:

• It doesn’t do authorization properly.
• It contains duplicated methods.
• Functionality that should be in models is incorporated into the controller.

What needs to be done:

1. latestresponseversion seems misnamed. It fetches all previous versions of a response (which is to say, all previous review versions by the current reviewer of the current author for the current assignment).
2. get_scores gets all the scores assigned in a particular response. A “response” is created when someone submits a review, a partner evaluation, a survey, etc.
3. The rereview method is 98 lines long. Several parts of it should be turned into methods. Sorting review versions is really not a controller responsibility; it would be better to do this in a model class (which class?) Ditto for determining whether a review is current (i.e., was done during the current assignment phase). This is a query that is made about a review (actually, about a response, which may be a review, author feedback, etc.). It should be placed in the appropriate model class.
4. rereview contains special code to check whether an assignment is “Jen’s assignment”; this was the first assignment we ever created with a multipart rubric. It was hard-coded into the system, rather than working on a rubric that was created in the normal way. It is probably impossible to remove this code without breaking that assignment, but it should be done in a separate method, and commented appropriately as a kludge.
5. Again in rereview, creating a new version of a review is a model responsibility, and should be moved out of the controller.
6. There are two (consecutive) copies of the edit method. The second appears to be the newer one, and, according to the rules for method definition, is the one that is currently in use. The first should be removed. Ditto for new_feedback and view--the 2nd version of each appears to be newer & should be kept.
7. Authorization to perform actions is not checked correctly. It is supposed to be done through the action_allowed? method at the beginning of the class definition. Different authorization should be required for different operations. For example, someone should be allowed to view a response if they wrote the response, or they are the person or on the team whose work the response applied to, or if they are an instructor or TA for the class. The person who wrote a response should be allowed to edit it, but not the person/team who was being reviewed, nor the instructor or TA for the class. Currently, authorization is denied by the redirect_when_disallowed method, which was an earlier, more error-prone way of controlling access. It should go away, now that the class has an action_allowed? method.

Changes Made

Response Controller

Method Name	Changes Made	Reason For Change
latestResponseVersion	Changed name to previous_responses	The name wasn't indicative of what the method did
new_feedback	Deleted the old new_feedback method	The old new_feedback method was not getting called due to ruby rules
view	Deleted the old view method	The old view method was not getting called due to ruby rules
redirect_when_disallowed	Moved all of the code from redirect_when_disallowed to action_allowed and deleted all of the previous references (action_allowed? gets called automatically)	Authorization to perform actions wasn't being performed correctly, it is supposed to be done through action_allowed?
action_allowed?
rereview	Moved logic for sorting response versions, and for getting the latest response to their own methods	The rereview method was becoming too large and confusing

Response Model

Method Name	Changes Made	Reason For Change
get_scores	Moved from controller (response_controller.rb) to model (response.rb)	The functionality in get_scores makes more sense to be implemented in the Model rather than in the controller

Re-factored Code

Removing duplicate methods

The ResponseController allows the user to create and edit responses to questionnaires, and the functionality changed over time, causing two new_feedback and view methods to be created; the oldest of which doesn't get called anymore.

Before Changes	After Changes
def new_feedback review = Response.find(params[:id]) if review reviewer = AssignmentParticipant.where(user_id: session[:user].id, parent_id: review.map.assignment.id).first map = FeedbackResponseMap.where(reviewed_object_id: review.id, reviewer_id: reviewer.id).first if map.nil? map = FeedbackResponseMap.create(:reviewed_object_id => review.id, :reviewer_id => reviewer.id, :reviewee_id => review.map.reviewer.id) end redirect_to :action => 'new', :id => map.map_id, :return => "feedback" else redirect_to :back end end def new_feedback review = Response.find(params[:id]) if review reviewer = AssignmentParticipant.where(user_id: session[:user].id, parent_id: review.map.assignment.id).first map = FeedbackResponseMap.where(reviewed_object_id: review.id, reviewer_id: reviewer.id).first if map.nil? #if no feedback exists by dat user den only create for dat particular response/review map = FeedbackResponseMap.create(:reviewed_object_id => review.id, :reviewer_id => reviewer.id, :reviewee_id => review.map.reviewer.id) end redirect_to :action => 'new', :id => map.id, :return => "feedback" else redirect_to :back end end	def new_feedback review = Response.find(params[:id]) if review reviewer = AssignmentParticipant.where(user_id: session[:user].id, parent_id: review.map.assignment.id).first map = FeedbackResponseMap.where(reviewed_object_id: review.id, reviewer_id: reviewer.id).first if map.nil? #if no feedback exists by dat user den only create for dat particular response/review map = FeedbackResponseMap.create(:reviewed_object_id => review.id, :reviewer_id => reviewer.id, :reviewee_id => review.map.reviewer.id) end redirect_to :action => 'new', :id => map.id, :return => "feedback" else redirect_to :back end end
def view @response = Response.find(params[:id]) return if redirect_when_disallowed(@response) @map = @response.map get_content @review_scores = Array.new @question_type = Array.new @questions.each do |question| @review_scores << Score.where(response_id: @map.response_id, question_id: question.id).first @question_type << QuestionType.find_by_question_id(question.id) end end def view @response = Response.find(params[:id]) return if action_allowed?(@response) @map = @response.map get_content get_scores(@response, @questions) end	def view @response = Response.find(params[:id]) return if action_allowed?(@response) @map = @response.map get_content get_scores(@response, @questions) end

Moving code to the proper place

The ResponseController allows the user to create and edit responses to questionnaires, in doing so, there needs to be some sort of authentication, and the proper place for that is in the action_allowed? method, however the un-refactored code did in the redirect_when_disallowed method. Moreover, once this code was moved to the action_allowed? method, all of the references to redirect_when_disallowed were removed (action_allowed? gets called automatically).

Before Changes

After Changes

def action_allowed? current_user end def redirect_when_disallowed(response) # For author feedback, participants need to be able to read feedback submitted by other teammates. # If response is anything but author feedback, only the person who wrote feedback should be able to see it. if response.map.read_attribute(:type) == 'FeedbackResponseMap' && response.map.assignment.team_assignment? team = response.map.reviewer.team unless team.has_user session[:user] redirect_to '/denied?reason=You are not on the team that wrote this feedback' else return false end response.map.read_attribute(:type) end !current_user_id?(response.map.reviewer.user_id) end

def action_allowed? # For author feedback, participants need to be able to read feedback submitted by other teammates. # If response is anything but author feedback, only the person who wrote feedback should be able to see it. if Response.where(id: params[:id]).empty? true elsif response = Response.find(params[:id]) if response.map.read_attribute(:type) == 'FeedbackResponseMap' && response.map.assignment.team_assignment? team = response.map.reviewer.team unless team.has_user session[:user] redirect_to '/denied?reason=You are not on the team that wrote this feedback' else return false end response.map.read_attribute(:type) end current_user_id?(response.map.reviewer.user_id) end end

Moving get_scores to the Response Model

The get_scores method was being implemented in the controller. Its function fits better in the model. As such, the method was moved and changed to retain the functionality of code that uses it. Since the variables it requires were no longer in scope, they're passed in as arguments. Also due to scope, the result has to be explicitly returned.

Before Changes

After Changes

In response_controller.rb def get_scores @review_scores = [] @question_type = [] @questions.each do |question| @review_scores << Score .where( response_id: @response.id, question_id: question.id ).first @question_type << QuestionType.find_by_question_id(question.id) end end

In response.rb def get_scores(response, questions) review_scores = [] question_type = [] questions.each do |question| review_scores << Score .where( response_id: response.id, question_id: question.id ).first question_type << QuestionType.find_by_question_id(question.id) end question_type end In response_controller.rb def view @response = Response.find(params[:id]) @map = @response.map get_content @question_type = @response.get_scores(@response, @questions) end

Steps to verify changes

Action Allowed

Action allowed is called before every method call to confirm whether or not the currently logged in user has the required privileges to complete the requested action. To test the functionality of this method one has to attempt to complete an action that they have privileges to complete, and confirm that they're allowed to complete it. One also has to attempt to complete an action that they don't have the privileges to complete, and confirm that they're not allowed to complete it.

Allowed

Log into the application with the user having a student's role (User Id: user5072, Password: password)

1. Click on Assignments, and you should see the following:

Not Allowed

Log into the application with the user having an instructor's role (User Id: user6, Password: password)

1. Click on Assignments, and you should see the following:

get_scores

Get scores is called anytime the scores for reviews are shown. Given that, the way to test its correct functionality is to navigate to a completed review and make sure the scores are shown and are correct.

Log into the application with the user having a student's role (User Id: user5072, Password: password)

1. Click on Assignments
2. Click on Writing assignment 1b, Spring 2013
3. Click on Others' Work
4. Click on Review done at --2013-03-01 23:57:55 UTC

Successful loading of this page confirms the get_scores method.

rereview

Rereview manages the versioning of multiple reviews for the same assignment. To test the correct functionality of review, one should attempt to update a review (i.e. 'rereview').

Log into the application with the user having a student's role (User Id: user5072, Password: password)

1. Click on Assignments
2. Click on Writing assignment 1b, Spring 2013
3. Click on Others' Work
4. Click on Update (beside Metaprogramming in dynamically typed languages)

Successful loading of this page confirms the rereview method.

References

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