CSC/ECE 517 Fall 2014/oss E1460 aua: Difference between revisions
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==Project Description== | ==Project Description== | ||
The <b>StudentQuiz controller</b> consists of methods involved in creating, scoring & recording responses of the quizzes taken by reviewers or students of the other teams with the same topic. | |||
<br>The changes that are needed to be done are described as follows:<ref>[https://docs.google.com/a/ncsu.edu/document/d/1FZCL9KWSdVNsX9BowuZ3gxbCOJoiWX-GVLctSZei3No/edit# GoogleDoc for our project requirements]</ref> | |||
<ol> | <ol> | ||
<li>Pluralize the class. (StudentQuizzesController)</li> | <li>Pluralize the class. (StudentQuizzesController)</li> | ||
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</pre> | </pre> | ||
=== | ===Follow principle of Boolean Zen=== | ||
---- | ---- | ||
In cases where a method only returns a boolean value by evaluating an expression (using the if..else construct), the if..else statement is redundant and can be eliminated. We have a method <b> graded? </b> that does this thing. Thus, we eliminated the if..else construct in the graded? method as it was redundant.<ref>[https://www.cs.utexas.edu/~scottm/cs312/handouts/slides/topic16_boolean_logic.pdf About Boolean Zen]</ref> | In cases where a method only returns a boolean value by evaluating an expression (using the if..else construct), the if..else statement is redundant and can be eliminated. We have a method <b> graded? </b> that does this thing. Thus, we eliminated the if..else construct in the graded? method as it was redundant.<ref>[https://www.cs.utexas.edu/~scottm/cs312/handouts/slides/topic16_boolean_logic.pdf About Boolean Zen]</ref> | ||
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===Code Cleanup=== | ===Code Cleanup=== | ||
---- | ---- | ||
At some places, we found certain statements and variable assignments that were not being used later on in the method or code. We have eliminated such unused statements, so that methods contain only code that is being used later on. This would improve the readability and the maintainability of the code. For example in the code below we eliminated the <b>@quiz_phase</b> and the <b>@num_quizzes_total</b> variables because they were not being used anywhere in the code. Also, since the <b>local</b> variables <b>quiz_due_date, deadline_type_id, participant</b> were not being used anywhere, we could eliminate the entire <b>if</b> block from the code below. We then converted the instance variable <b>participant</b> to a local variable because it was not being used in the corresponding view. | At some places, we found certain statements and variable assignments that were not being used later on in the method or code. We have eliminated such unused statements, so that methods contain only code that is being used later on. This would improve the readability and the maintainability of the code. For example in the code below we eliminated the <b>@quiz_phase</b> and the <b>@num_quizzes_total</b> variables because they were not being used anywhere in the code. Also, since the <b>local</b> variables <b>quiz_due_date, deadline_type_id, participant</b> were not being used anywhere, we could eliminate the entire <b>if</b> block from the code below. We then converted the instance variable <b>participant</b> to a local variable because it was not being used in the corresponding view. This is illustrated well in the example mentioned above for the [http://wiki.expertiza.ncsu.edu/index.php/CSC/ECE_517_Fall_2014/oss_E1460_aua#RESTful_style_implementation RESTful style implementation]. | ||
===Following Ruby Style Guidelines (Global Rules)=== | ===Following Ruby Style Guidelines (Global Rules)=== | ||
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---- | ---- | ||
<b>Before Refactoring</b> | <b>Before Refactoring</b> | ||
<br> Method: record_response | <br> Method: record_response | ||
<pre> | <pre> | ||
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<b>After Refactoring</b> | <b>After Refactoring</b> | ||
<br> Method: calculate_score | <br> Method: calculate_score | ||
<pre> | <pre> | ||
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====Use good conditional statements==== | ====Use good conditional statements==== | ||
---- | ---- | ||
Using unless is a good practice. But it is not a good practice to use unless and ! within the condition. | Using unless is a good practice. But it is not a good practice to use unless and ! within the condition. Instead we could use an if condition itself. | ||
<b>Before Refactoring</b> | <b>Before Refactoring</b> | ||
<br> Method: record_response | <br> Method: record_response | ||
<pre> | <pre> | ||
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<b>After Refactoring</b> | <b>After Refactoring</b> | ||
<br> Method: calculate_score | <br> Method: calculate_score | ||
<pre> | <pre> | ||
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====Use of Routing Helpers==== | ====Use of Routing Helpers==== | ||
---- | ---- | ||
Routing helpers are a simpler alternative to the otherwise complex hard coded URLs which reduce the readability of the code.Routing helpers allow us to declare possible common routes for a given controller. Routing helpers have been implemented since they maintain consistency even if changes are made to the routing paths. | Routing helpers are a simpler alternative to the otherwise complex hard coded URLs which reduce the readability of the code. Routing helpers allow us to declare possible common routes for a given controller. Routing helpers have been implemented since they maintain consistency even if changes are made to the routing paths. | ||
<b>Before Refactoring</b>: | <b>Before Refactoring</b>: | ||
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---- | ---- | ||
Rails 4 conventions dictate the use of a fat model and skinny controller. | Rails 4 conventions dictate the use of a fat model and skinny controller. | ||
It is better to | It is better to place the search function in the model rather than placing it in the controller. | ||
The search code belonged to the quiz_response_map model, since it queries that particular table in the | The search code belonged to the <b>quiz_response_map</b> model, since it queries that particular table in the database. | ||
The code was extracted into the | The code was extracted into the <b>get_mappings_for_reviewer</b> method and placed in the file <b>quiz_response_map.rb</b>. This method was then called from the <b>StudentQuizzes</b> controller. | ||
<ref name = "stackoverflow">[http://stackoverflow.com/questions/14044681/fat-models-and-skinny-controllers-sounds-like-creating-god-models Fat Models and Skinny Controllers.]</ref> | |||
<b>Before Refactoring</b> | <b>Before Refactoring</b> | ||
<br> student_quizzes_controller.rb | <br> student_quizzes_controller.rb | ||
<br> Method : index | |||
<pre> | <pre> | ||
@quiz_mappings = QuizResponseMap.where(reviewer_id: participant.id) | @quiz_mappings = QuizResponseMap.where(reviewer_id: participant.id) | ||
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<b>After Refactoring</b> | <b>After Refactoring</b> | ||
<br> student_quizzes_controller.rb | |||
<br> Method : index | |||
<pre> | <pre> | ||
@quiz_mappings = QuizResponseMap.get_mappings_for_reviewer(participant.id) | @quiz_mappings = QuizResponseMap.get_mappings_for_reviewer(participant.id) | ||
</pre> | |||
<br> quiz_response_map.rb | |||
<pre> | |||
def self.get_mappings_for_reviewer(participant_id) | |||
return QuizResponseMap.where(reviewer_id: participant_id) | |||
end | |||
</pre> | </pre> | ||
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We have made certain changes in the logic of the methods calculate_score and record_response (previously the code of both these methods was only in record_response) primarily to improve the existing logic and eliminate redundant code. These changes are described as follows: | We have made certain changes in the logic of the methods calculate_score and record_response (previously the code of both these methods was only in record_response) primarily to improve the existing logic and eliminate redundant code. These changes are described as follows: | ||
* The score variable was already being set to 0 on the loop entry, therefore it was redundant to reset score to zero again. Thus, we eliminated this line of code inside the if statement. | * The <b>score</b> variable was already being set to 0 on the loop entry, therefore it was redundant to reset score to zero again. Thus, we eliminated this line of code inside the if statement. | ||
<b>Before Refactoring</b> | <b>Before Refactoring</b> | ||
<pre> | <pre> | ||
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---- | ---- | ||
* The new_scores and scores array stored almost the similar values. The scores contained a copy of the value that the new_scores array contained. Therefore we eliminated the new_scores array and are performing all the operations only on the scores array. | * The <b>new_scores</b> and <b>scores</b> array stored almost the similar values. The <b>scores</b> array contained a copy of the value that the <b>new_scores</b> array contained. Therefore we eliminated the <b>new_scores</b> array and are performing all the operations only on the <b>scores</b> array. | ||
<b>Before Refactoring</b> | <b>Before Refactoring</b> | ||
<pre> | <pre> | ||
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---- | ---- | ||
* The record_response function was performing two distinct operations : One operation was saving the response to the | * The <b>record_response</b> function was performing two distinct operations : One operation was saving the response to the database and the other was to calculate the score for the questions. We created a new function <b>calculate_score</b> that would calculate the score for the questions and <b>record_response</b> now only performs the task of saving responses to the database. By doing this, we followed the <b>Single Responsibility O-O Design Principle for methods</b> mentioned by <b> Mr. Robert C. Martin </b> which states that "Every software module should have only one reason to change"<ref>[http://www.codeproject.com/Articles/567768/Object-Oriented-Design-Principles O-O Design Principles]</ref> | ||
<b>Before Refactoring</b> | <b>Before Refactoring</b> | ||
<pre> | <pre> | ||
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# New calculate_score | # New calculate_score | ||
def calculate_score map, response | def calculate_score map, response | ||
# | questionnaire = Questionnaire.find(map.reviewed_object_id) | ||
scores = Array.new | |||
valid = true | |||
questions = Question.where(questionnaire_id: questionnaire.id) | |||
questions.each do |question| | |||
score = 0 | |||
correct_answers = QuizQuestionChoice.where(question_id: question.id, iscorrect: true) | |||
ques_type = (QuestionType.where( question_id: question.id)).q_type | |||
if ques_type.eql? 'MCC' | |||
if params["#{question.id}"].nil? | |||
valid = false | |||
else | |||
params["#{question.id}"].each do |choice| | |||
correct_answers.each do |correct| | |||
if choice.eql? correct.txt | |||
score += 1 | |||
end | |||
end | |||
new_score = Score.new comments: choice, question_id: question.id, response_id: response.id | |||
unless new_score.valid? | |||
valid = false | |||
end | |||
scores.push(new_score) | |||
end | |||
if score.eql? correct_answers.count && score == params["#{question.id}"].count | |||
score = 1 | |||
else | |||
score = 0 | |||
end | |||
scores.each do |score_update| | |||
score_update.score = score | |||
end | |||
end | |||
else | |||
correct_answer = correct_answers.first | |||
if ques_type.eql? 'Essay' | |||
score = -1 | |||
elsif correct_answer && params["#{question.id}"]== correct_answer.txt | |||
score = 1 | |||
end | |||
new_score = Score.new :comments => params["#{question.id}"], :question_id => question.id, :response_id => response.id, :score => score | |||
if new_score.comments.empty? || new_score.comments.nil? | |||
valid = false | |||
end | |||
scores.push(new_score) | |||
end | |||
end | |||
if valid | |||
scores.each do |score| | |||
score.save | |||
end | |||
redirect_to :controller => 'student_quizzes', :action => 'finished_quiz', :map_id => map.id | |||
else | |||
flash[:error] = "Please answer every question." | |||
redirect_to :action => :take_quiz, :assignment_id => params[:assignment_id], :questionnaire_id => questionnaire.id | |||
end | |||
end | |||
</pre> | </pre> | ||
==References== | ==References== | ||
<references/><br> | <references/><br> |
Latest revision as of 02:46, 6 November 2014
Expertiza - Refactoring StudentQuizController
Expertiza is a web application developed using Ruby on Rails that serves as a peer-review system. The application allows students to submit and peer-review learning objects (articles, code, web sites, etc)<ref>Expertiza on GitHub</ref><ref>Expertiza Wiki Page</ref>. It is an open source project and it's codebase is maintained in GitHub. We are contributing to Expertiza as a part of our Object-Oriented Design and Development's Open-Source Software (OSS) Project. Our goal in this project is to refactor the StudentQuiz controller. In this Wiki Page, we would be explaining the changes that we have made for the same.
Project Description
The StudentQuiz controller consists of methods involved in creating, scoring & recording responses of the quizzes taken by reviewers or students of the other teams with the same topic.
The changes that are needed to be done are described as follows:<ref>GoogleDoc for our project requirements</ref>
- Pluralize the class. (StudentQuizzesController)
- Rename methods to conform to RESTful style. (e.g. :- Rename the list method to index.)
- Reduce the number of instance variables per controller action.
- Review Method graded? for boolean zen.
- Perform Code cleanup by removing unused code.
- Use good Ruby style guidelines in the code.
- Split a method performing multiple tasks, into seperate methods.
- Fix logical errors in the code.
Modifications made to the Existing Code
Pluralized the class name StudentQuizController
As per the Rails convention the controller class names are suggested to be plural. This helps in generating RESTful routing URI helpers. Also, naming the classes as plural seems intuitive.<ref>Using the Singular or Plural controller and helper names in Rails</ref>. We used the refactor functionality in RubyMine to rename the StudentQuiz controller class to StudentQuizzes.
The following files were modified and/or renamed.
app/controllers/review_mapping_controller.rb app/controllers/{student_quiz_controller.rb → student_quizzes_controller.rb} app/helpers/student_quiz_helper.rb app/helpers/student_quizzes_helper.rb app/views/questionnaires/view.html.erb app/views/{student_quiz → student_quizzes}/_quiz_form.html.erb app/views/{student_quiz → student_quizzes}/_responses.html.erb app/views/{student_quiz → student_quizzes}/_set_dynamic_quiz.html.erb app/views/{student_quiz → student_quizzes}/_set_self_quiz.html.erb app/views/{student_quiz → student_quizzes}/finished_quiz.html.erb app/views/{student_quiz → student_quizzes}/grade_essays.html.erb app/views/{student_quiz → student_quizzes}/list.html.erb app/views/{student_quiz → student_quizzes}/take_quiz.html.erb app/views/student_task/view.html.erb app/views/tree_display/actions/_assignments_actions.html.erb test/functional/{student_quiz_controller_test.rb → student_quizzes_controller_test.rb} test/test_helper.rb test/unit/helpers/student_quiz_helper_test.rb test/unit/helpers/student_quizzes_helper_test.rb
The detailed change-set for this refactor can be seen here.
RESTful style implementation
The purpose of the list method in the StudentQuizzes controller is to list all the quizzes that are available to a particular user for a particular assignment. RESTful guidelines state that a method that returns a list of all available objects, in this case the quizzes, should be named as index. Therefore, we renamed the list method to the index method in the controller and in all the files that had references to the list method of the student_quizzes_controller (For e.g. :- The view finished_quiz.html.erb of the Student Quiz controller, the review_mapping controller.rb etc.).
Before Refactoring :
Method : list
def list @participant = AssignmentParticipant.find(params[:id]) return unless current_user_id?(@participant.user_id) @assignment = Assignment.find(@participant.parent_id) # Find the current phase that the assignment is in. @quiz_phase = @assignment.get_current_stage(AssignmentParticipant.find(params[:id]).topic_id) @quiz_mappings = QuizResponseMap.where(reviewer_id: @participant.id) # Calculate the number of quizzes that the user has completed so far. @num_quizzes_total = @quiz_mappings.size @num_quizzes_completed = 0 @quiz_mappings.each do |map| @num_quizzes_completed += 1 if map.response end if @assignment.staggered_deadline? @quiz_mappings.each { |quiz_mapping| if @assignment.team_assignment? participant = AssignmentTeam.get_first_member(quiz_mapping.reviewee_id) else participant = quiz_mapping.reviewee end if !participant.nil? and !participant.topic_id.nil? quiz_due_date = TopicDeadline.where(topic_id: participant.topic_id, deadline_type_id: 1).first end } deadline_type_id = DeadlineType.find_by_name('quiz').id end end }
After Refactoring :
Method : index
def index participant = AssignmentParticipant.find(params[:id]) return unless current_user_id?(participant.user_id) @assignment = Assignment.find(participant.parent_id) @quiz_mappings = QuizResponseMap.get_mappings_for_reviewer(participant.id) end
Instance Variable Reductions
In Rails, the data is shared between the controllers and views through the instance variables. The instance variabIes that are set during the execution a particular controller method are accessible to the view. Excessive usage of this standard method of data sharing between the controller and the view results in increased coupling between them <ref>Decreasing Controller-View Coupling in Rails</ref>. Increased coupling results in several problems, including less maintainability of code, difficulty in code reuse etc. <ref>Disadvantages of Tight Coupling - Wikipedia</ref> Thus, we need to reduce coupling as much as possible and in this case it can be achieved by reducing as many instance variables as possible in the controller. Therefore, we have refactored our code in order to eliminate unnecessary instance variables and to convert all the instance variables to local variables that are not used in the views.
In the take_quiz method, the following instance variables were removed:
- Changed the quizzes instance variable to a local variable.
- Eliminated the instance variable assignment which was not being used anywhere.
- Eliminated the local variable teams which was not being used any where
Before Refactoring
def self.take_quiz assignment_id , reviewer_id @quizzes = Array.new reviewer = Participant.where(user_id: reviewer_id, parent_id: assignment_id).first @assignment = Assignment.find(assignment_id) teams = TeamsUser.where(user_id: reviewer_id) Team.where(parent_id: assignment_id).each do |quiz_creator| unless TeamsUser.find_by_team_id(quiz_creator.id).user_id == reviewer_id Questionnaire.where(instructor_id: quiz_creator.id).each do |questionnaire| if !@assignment.team_assignment? unless QuizResponseMap.where(reviewed_object_id: questionnaire.id, reviewer_id: reviewer.id).first @quizzes.push(questionnaire) end else unless QuizResponseMap.where(reviewed_object_id: questionnaire.id, reviewer_id: reviewer_id).first @quizzes.push(questionnaire) end end end end end return @quizzes end
After Refactoring
def self.take_quiz assignment_id , reviewer_id quizzes = Array.new reviewer = Participant.where(user_id: reviewer_id, parent_id: assignment_id).first Team.where(parent_id: assignment_id).each do |quiz_creator| unless TeamsUser.find_by_team_id(quiz_creator.id).user_id == reviewer_id Questionnaire.where(instructor_id: quiz_creator.id).each do |questionnaire| unless QuizResponseMap.where(reviewed_object_id: questionnaire.id, reviewer_id: reviewer.id).first quizzes.push(questionnaire) end end end end return quizzes end
Follow principle of Boolean Zen
In cases where a method only returns a boolean value by evaluating an expression (using the if..else construct), the if..else statement is redundant and can be eliminated. We have a method graded? that does this thing. Thus, we eliminated the if..else construct in the graded? method as it was redundant.<ref>About Boolean Zen</ref>
Before Refactoring
Method : graded?
def graded?(response, question) if Score.where(question_id: question.id, response_id: response.id).first return true else return false end end
After Refactoring
Method : graded?
def graded?(response, question) return (Score.where(question_id: question.id, response_id: response.id).first) end
Code Cleanup
At some places, we found certain statements and variable assignments that were not being used later on in the method or code. We have eliminated such unused statements, so that methods contain only code that is being used later on. This would improve the readability and the maintainability of the code. For example in the code below we eliminated the @quiz_phase and the @num_quizzes_total variables because they were not being used anywhere in the code. Also, since the local variables quiz_due_date, deadline_type_id, participant were not being used anywhere, we could eliminate the entire if block from the code below. We then converted the instance variable participant to a local variable because it was not being used in the corresponding view. This is illustrated well in the example mentioned above for the RESTful style implementation.
Following Ruby Style Guidelines (Global Rules)
At many places in the code we found that the Ruby Style Guidelines were not followed. We have refactored the code so that it uses the good code style guidelines. The following are some of the refactorings the we have done:-
Used .eql? instead of "=="
Before Refactoring
Method : finished_quiz
if score.score == -1
After Refactoring
if score.score.eql? -1
Eliminated the "== true/false" check
Before Refactoring
Method : finished_quiz
if essay_not_graded == true
After Refactoring
if essay_not_graded
Use `&&` and `||` rather than `and` and `or` to keep boolean precedence
Before Refactoring
Method: record_response
elsif correct_answer and params["#{question.id}"] == correct_answer.txt
After Refactoring
Method: calculate_score
elsif correct_answer && params["#{question.id}"]== correct_answer.txt
Use key: ‘value’, not :key => ‘value’
Before Refactoring
Method: record_response
new_score = Score.new :comments => choice, :question_id => question.id, :response_id => @response.id
After Refactoring
Method: calculate_score
new_score = Score.new comments: choice, question_id: question.id, response_id: response.id
Replace find_by_... with a where command
Before Refactoring
Method: record_response
if (QuestionType.find_by_question_id question.id).q_type == 'MCC'
After Refactoring
Method: calculate_score
ques_type = (QuestionType.where( question_id: question.id)).q_type if ques_type.eql? 'MCC'
Used .nil? instead of "== nil"
Before Refactoring
Method: record_response
if params["#{question.id}"] == nil
After Refactoring
Method: calculate_score
if params["#{question.id}"].nil?
Used a Boolean variable when that is sufficient
Before Refactoring
Method: record_response
valid = 1 if valid == 0
After Refactoring
Method: calculate_score
valid = false if valid
Use good conditional statements
Using unless is a good practice. But it is not a good practice to use unless and ! within the condition. Instead we could use an if condition itself.
Before Refactoring
Method: record_response
unless new_score.comments != "" && new_score.comments valid = false
After Refactoring
Method: calculate_score
if new_score.comments.empty? || new_score.comments.nil? valid = false
Use of Routing Helpers
Routing helpers are a simpler alternative to the otherwise complex hard coded URLs which reduce the readability of the code. Routing helpers allow us to declare possible common routes for a given controller. Routing helpers have been implemented since they maintain consistency even if changes are made to the routing paths.
Before Refactoring:
config.rb does not contain a student_quizzes resource
review_mapping_controller.rb
redirect_to :controller => 'student_quizzes', :action => 'index', :id => params[:participant_id]
After Refactoring
config.rb
resources :student_quizzes, :only => [:index]
review_mapping_controller.rb
redirect_to student_quizzes_path(:id => params[:participant_id])
Replace controller method with a model method
Rails 4 conventions dictate the use of a fat model and skinny controller. It is better to place the search function in the model rather than placing it in the controller. The search code belonged to the quiz_response_map model, since it queries that particular table in the database. The code was extracted into the get_mappings_for_reviewer method and placed in the file quiz_response_map.rb. This method was then called from the StudentQuizzes controller. <ref name = "stackoverflow">Fat Models and Skinny Controllers.</ref>
Before Refactoring
student_quizzes_controller.rb
Method : index
@quiz_mappings = QuizResponseMap.where(reviewer_id: participant.id)
After Refactoring
student_quizzes_controller.rb
Method : index
@quiz_mappings = QuizResponseMap.get_mappings_for_reviewer(participant.id)
quiz_response_map.rb
def self.get_mappings_for_reviewer(participant_id) return QuizResponseMap.where(reviewer_id: participant_id) end
Changes made in method logic
We have made certain changes in the logic of the methods calculate_score and record_response (previously the code of both these methods was only in record_response) primarily to improve the existing logic and eliminate redundant code. These changes are described as follows:
- The score variable was already being set to 0 on the loop entry, therefore it was redundant to reset score to zero again. Thus, we eliminated this line of code inside the if statement.
Before Refactoring
questions.each do |question| score = 0 if (QuestionType.find_by_question_id question.id).q_type == 'MCC' score = 0
After Refactoring
questions.each do |question| score = 0 if ques_type.eql? 'MCC' # Eliminated score = 0 over here
- The variable correct_answer stored multiple values as the where condition to which it was assigned was returning multiple values. Therefore it seemed more intuitive to rename correct_answer to correct_answers so that it is apparent that it contains multiple values.
Before Refactoring
correct_answer = QuizQuestionChoice.where(question_id: question.id, iscorrect: 1)
After Refactoring
correct_answers = QuizQuestionChoice.where(question_id: question.id, iscorrect: true)
- The below piece of code found out the question type twice in the same loop. Therefore we extracted it and assigned it to a local variable so that the query is executed only once.
Before Refactoring
# First Query if (QuestionType.find_by_question_id question.id).q_type == 'MCC' # Repetition of the query in the same loop if (QuestionType.find_by_question_id question.id).q_type == 'Essay'
After Refactoring
# Querying only once and assigning it to a local variable ques_type ques_type = (QuestionType.where( question_id: question.id)).q_type # Usage 1 of ques_type if ques_type.eql? 'MCC' # Usage 2 of ques_type if ques_type.eql? 'Essay'
- The new_scores and scores array stored almost the similar values. The scores array contained a copy of the value that the new_scores array contained. Therefore we eliminated the new_scores array and are performing all the operations only on the scores array.
Before Refactoring
# Part 1 new_score = Score.new :comments => choice, :question_id => question.id, :response_id => @response.id unless new_score.valid? valid = 1 end new_scores.push(new_score) # Part 2 new_scores.each do |score_update| score_update.score = score scores.push(score_update) end
After Refactoring
# Part 1 new_score = Score.new comments: choice, question_id: question.id, response_id: response.id unless new_score.valid? valid = false end scores.push(new_score) # Part 2 scores.each do |score_update| score_update.score = score end
- The logic to compute the final score for a multiple-choice, multiple-correct type of question seemed to be incorrect and therefore we fixed it.
Before Refactoring
# Part 1 of the Scoring Logic questions.each do |question| score = 0 if (QuestionType.find_by_question_id question.id).q_type == 'MCC' score = 0 if params["#{question.id}"] == nil valid = 1 else correct_answer = QuizQuestionChoice.where(question_id: question.id, iscorrect: 1) params["#{question.id}"].each do |choice| correct_answer.each do |correct| if choice == correct.txt score += 1 end # Part 2 of the scoring logic which seems to award full points even if you marked some extra options apart from marking all correct answers unless score == correct_answer.count score = 0 else score = 1 end
After Refactoring
# Part 1 of the Scoring Logic questions.each do |question| score = 0 correct_answers = QuizQuestionChoice.where(question_id: question.id, iscorrect: true) ques_type = (QuestionType.where( question_id: question.id)).q_type if ques_type.eql? 'MCC' if params["#{question.id}"].nil? valid = false else params["#{question.id}"].each do |choice| correct_answers.each do |correct| if choice.eql? correct.txt score += 1 end # Part 2 of the scoring logic - We have also compared the number of options the user selected to the total number of correct answers if score.eql? correct_answers.count && score == params["#{question.id}"].count score = 1 else score = 0 end
- The record_response function was performing two distinct operations : One operation was saving the response to the database and the other was to calculate the score for the questions. We created a new function calculate_score that would calculate the score for the questions and record_response now only performs the task of saving responses to the database. By doing this, we followed the Single Responsibility O-O Design Principle for methods mentioned by Mr. Robert C. Martin which states that "Every software module should have only one reason to change"<ref>O-O Design Principles</ref>
Before Refactoring
def record_response @map = ResponseMap.find(params[:map_id]) @response = Response.new() @response.map_id = params[:map_id] @response.created_at = DateTime.current @response.updated_at = DateTime.current @response.save @questionnaire = Questionnaire.find(@map.reviewed_object_id) scores = Array.new new_scores = Array.new valid = 0 questions = Question.where(questionnaire_id: @questionnaire.id) questions.each do |question| score = 0 if (QuestionType.find_by_question_id question.id).q_type == 'MCC' score = 0 if params["#{question.id}"] == nil valid = 1 else correct_answer = QuizQuestionChoice.where(question_id: question.id, iscorrect: 1) params["#{question.id}"].each do |choice| correct_answer.each do |correct| if choice == correct.txt score += 1 end end new_score = Score.new :comments => choice, :question_id => question.id, :response_id => @response.id unless new_score.valid? valid = 1 end new_scores.push(new_score) end unless score == correct_answer.count score = 0 else score = 1 end new_scores.each do |score_update| score_update.score = score scores.push(score_update) end end else score = 0 correct_answer = QuizQuestionChoice.where(question_id: question.id, iscorrect: 1).first if (QuestionType.find_by_question_id question.id).q_type == 'Essay' score = -1 elsif correct_answer and params["#{question.id}"] == correct_answer.txt score = 1 end new_score = Score.new :comments => params["#{question.id}"], :question_id => question.id, :response_id => @response.id, :score => score unless new_score.comments != "" && new_score.comments valid = 1 end scores.push(new_score) end end if valid == 0 scores.each do |score| score.save end redirect_to :controller => 'student_quizzes', :action => 'finished_quiz', :map_id => @map.id else flash[:error] = "Please answer every question." redirect_to :action => :take_quiz, :assignment_id => params[:assignment_id], :questionnaire_id => @questionnaire.id end end
After Refactoring
# New record_response method def record_response map = ResponseMap.find(params[:map_id]) response = Response.new response.map_id = params[:map_id] response.created_at = DateTime.current response.updated_at = DateTime.current response.save calculate_score map,response end # New calculate_score def calculate_score map, response questionnaire = Questionnaire.find(map.reviewed_object_id) scores = Array.new valid = true questions = Question.where(questionnaire_id: questionnaire.id) questions.each do |question| score = 0 correct_answers = QuizQuestionChoice.where(question_id: question.id, iscorrect: true) ques_type = (QuestionType.where( question_id: question.id)).q_type if ques_type.eql? 'MCC' if params["#{question.id}"].nil? valid = false else params["#{question.id}"].each do |choice| correct_answers.each do |correct| if choice.eql? correct.txt score += 1 end end new_score = Score.new comments: choice, question_id: question.id, response_id: response.id unless new_score.valid? valid = false end scores.push(new_score) end if score.eql? correct_answers.count && score == params["#{question.id}"].count score = 1 else score = 0 end scores.each do |score_update| score_update.score = score end end else correct_answer = correct_answers.first if ques_type.eql? 'Essay' score = -1 elsif correct_answer && params["#{question.id}"]== correct_answer.txt score = 1 end new_score = Score.new :comments => params["#{question.id}"], :question_id => question.id, :response_id => response.id, :score => score if new_score.comments.empty? || new_score.comments.nil? valid = false end scores.push(new_score) end end if valid scores.each do |score| score.save end redirect_to :controller => 'student_quizzes', :action => 'finished_quiz', :map_id => map.id else flash[:error] = "Please answer every question." redirect_to :action => :take_quiz, :assignment_id => params[:assignment_id], :questionnaire_id => questionnaire.id end end
References
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