CSC/ECE 517 Fall 2017/E1777 Coherent specification of review requirements.rb: Difference between revisions

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==E1553. Refactoring the Versions Controller==
==E1777. OSS Project Green: Coherent specification of review requirements==


This page provides a description of the Expertiza based OSS project.  
This page provides a description of the Expertiza based OSS project.  
Line 14: Line 14:
The following tasks were accomplished in this project:
The following tasks were accomplished in this project:


* Improved the clarity of code by improving the variable and parameter names.
* Improved the punctuation, syntax and the capitalization of statements in the review strategy tab.  
* Long character strings were taken and given appropriate names.
* Provided information buttons to elaborate difference between the synonymous statements present in review strategy tab.
* Handled pagination by a separate helper module, which can be used by multiple controllers.
* Handled issue of project submission assignment process to ensure every submission receives required number of reviews.
* Implemented action_allowed for access_control to prevent unauthorized access of methods.
* Prevented displaying of all versions for all users and tables when a user views the index page.
* Added missing CRUD methods to Versions Controller
* Added RSPEC testcases for testing changes done in Versions Controller
 
===About Versions Controller===
This class manages different versions of reviews. If a reviewer reviews a submission, and after that, the author revises the submission, the next time the reviewer does a review (s)he will create a new version. Sometimes it’s necessary to find the current version of a review; sometimes it’s necessary to find all versions. Similarly, a user may want to delete the current version of a review, or all versions of a review. Pagination of versions helps the user to view a subset of versions at a time. Considering the huge number of versions in the system, it is very useful to have a pagination mechanism and a filtering mechanism which can be applied on the whole set of versions. The idea is to display the versions in an ordered, comprehensible and logical manner. In Expertiza the gem ‘will_paginate’ is used to achieve pagination.


===Current Implementation===
===Current Implementation===
Line 29: Line 22:


=====Functionality=====
=====Functionality=====
* Any user irrespective of his/ her privileges can view all the versions.
* In Expertiza, there are two ways of assigning reviews to reviewers: either the instructor decides who reviews whom (“instructor-selected”), or “auto-selected,” in which case reviews are not assigned until a student seeks to choose something to review. To allow reviewers a larger set of topics to choose from, the instructor can set the threshold (on the Review Strategy tab of assignment creation/editing) to some integer k > 0. Then any submission that has within k reviews of the fewest number can be chosen by a new reviewer. Let’s say that all submissions have at least 1 review. If k = 3, then the reviewer can choose any topic where there is a submission that has 4 or fewer reviews so far. Suppose that the minimum number of reviews for any submission is 2, but that I have reviewed all the submissions that have only 2 reviews. Then I’m not allowed to review at all (unless k > 0).
::The versions which a particular user can view should be restricted based on the privileges of the user. For instance, only a user with Administrator privileges should be able to view all the versions in the system. However, that is not the case now. Every user can view all the versions irrespective of whether the user is a student or an administrator.
* A reviewer does not receive a submission to review, because all the submissions have either fulfilled the review requirements or has already been reviewed by this particular reviewer.  
* Any user can delete any version
* The Review Strategy tab includes options, "Set Allowed Number of Reviews per reviewer" and "Set Required Number of Reviews per reviewer."
::The versions which a particular user can delete should be restricted based on the privileges of the user. For instance, a student should not be allowed to delete any version. According to the current implementation any user can delete any version in the system.
* The capitalization and punctuation in the statements ***** under the review strategy tab are random.
* Filtering of versions were restricted to the current user
* On the Review Strategy tab of assignment creation, the "Maximum number of reviews per submission" checks  the number of reviews that have been assigned to reviewers  instead of checking the number of reviews that are submitted by the users. This means that if reviewers choose submissions and don't submit their reviews,  those submissions cannot be reviewed by anyone else.
::The filtering options on versions were restricted to the current user. Sometimes a user might want to view versions associated with other users. For instance, an instructor might want to view the list of versions created by a particular student. This is not possible with the current implementation.


=====Drawbacks and Solutions=====
=====Drawbacks and Solutions=====
* '''Problem 1''': The method paginate_list is doing more than one thing.
* '''Problem 1''': The system always allocates to a reviewer, that submission which has received a minimum number of reviews. If a reviewer has already reviewed the submission with the minimum number of reviews and he requests for a new submission to review, he does not receive any submission to review.
::The method paginate_list was building a complex search criteria based on the input params, getting the list of versions from the Database matching this search criteria and then calling the Page API. All these tasks in a single method made it difficult to understand.
* '''Solution''': This issue has been fixed previously. The reviewer will get assigned a submission even if it has fulfilled the required number of reviews, to ensure that the reviewer always receives a new submission to review as long as it is not his own.  
<pre>
* '''Problem 2''': The two statements "Set Allowed Number of Reviews per reviewer" and "Set Required Number of Reviews per reviewer." are not well differentiated. It can very confusing for an instructor to give values for them.
# For filtering the versions list with proper search and pagination.
  def paginate_list(id, user_id, item_type, event, datetime)
    # Set up the search criteria
    criteria = ''
    criteria = criteria + "id = #{id} AND " if id && id.to_i > 0
    if current_user_role? == 'Super-Administrator'
      criteria = criteria + "whodunnit = #{user_id} AND " if user_id && user_id.to_i > 0
    end
    criteria = criteria + "whodunnit = #{current_user.try(:id)} AND " if current_user.try(:id) && current_user.try(:id).to_i > 0
    criteria = criteria + "item_type = '#{item_type}' AND " if item_type && !(item_type.eql? 'Any')
    criteria = criteria + "event = '#{event}' AND " if event && !(event.eql? 'Any')
    criteria = criteria + "created_at >= '#{time_to_string(params[:start_time])}' AND "
    criteria = criteria + "created_at <= '#{time_to_string(params[:end_time])}' AND "
 
    if current_role == 'Instructor' || current_role == 'Administrator'


    end
* '''Solution''': Information buttons have been provided beside these statements in the review strategy tab to make sure that the instructor knows the difference between the two.
* '''Problem 3''': The capitalization and punctuations of statements **** are incorrect.
* '''Solution''':  This view has been fixed by making changes in the respective files.


    # Remove the last ' AND '
    criteria = criteria[0..-5]


    versions = Version.page(params[:page]).order('id').per_page(25).where(criteria)
    versions
  end
</pre>
* '''Solution''': The implementation has been changed in such a way that the versions which a user is allowed to see depends on the privileges of the user. The approach we have taken is as follows:
**An administrator can see all the versions
**An instructor can see all the versions created by him and other users who are in his course or are participants in the assignments he creates.
**A TA can see all the versions created by him and other users who are in the course for which he/ she assists.
**A Student can see all the versions created by him/ her.
* '''Problem 2''': The search criteria created in the method paginate_list was difficult to comprehend.
::The code which builds the search criteria in the method paginate_list uses many string literals and conditions and is hardly intuitive. The programmer will have to spend some time to understand what the code is really doing.
* '''Solution''': The implementation has been changed. A student is not allowed to delete any versions now. Other types of users, for instance administrators, instructors and TAs are allowed to delete only the versions they are authorized to view.
* '''Problem 3''': The paginate method can be moved to a helper class.
::VersionsController is not the only component which require to paginate items. There are other components too. For instance, the UsersController has to paginate the list of users. Hence the Paginate method can be moved to a helper class which can be accessed by other components as well.
* '''Solution''': The filtering options has also been enhanced. The current user can now choose as part of the version search filter any user from a list of users if the current user is authorized to see the versions created by that user.
===New Implementation===
*The method paginate_list has been split into 2 methods now.  
*The method paginate_list has been split into 2 methods now.  
** BuildSearchCriteria – as the name suggests the sole purpose of this method is to build a search criteria based on the input search filters when the current user initiates a search in versions.
** BuildSearchCriteria – as the name suggests the sole purpose of this method is to build a search criteria based on the input search filters when the current user initiates a search in versions.
Line 83: Line 43:
:First the search criteria is built, then the criteria is applied to versions in the database to get all versions which matches the criteria and then the retrieved versions are paginated.
:First the search criteria is built, then the criteria is applied to versions in the database to get all versions which matches the criteria and then the retrieved versions are paginated.
<pre>
<pre>
   # pagination.
   </pre>
  def paginate_list(versions)
    paginate(versions, VERSIONS_PER_PAGE);
  end
 
  def BuildSearchCriteria(id, user_id, item_type, event)
    # Set up the search criteria
    search_criteria = ''
    search_criteria = search_criteria + add_id_filter_if_valid(id).to_s
    if current_user_role? == 'Super-Administrator'
      search_criteria = search_criteria + add_user_filter_for_super_admin(user_id).to_s
    end
    search_criteria = search_criteria + add_user_filter
    search_criteria = search_criteria + add_version_type_filter(item_type).to_s
    search_criteria = search_criteria + add_event_filter(event).to_s
    search_criteria = search_criteria + add_date_time_filter
    search_criteria
  end
</pre>
* The string literals and conditions in the method paginate_list were replaced with methods with intuitive names so that the programmer can understand the code more easily. We also removed an empty if clause and a redundant statement.
<pre>
  def add_id_filter_if_valid (id)
    "id = #{id} AND " if id && id.to_i > 0
  end
 
  def add_user_filter_for_super_admin (user_id)
    "whodunnit = #{user_id} AND " if user_id && user_id.to_i > 0
  end
 
  def add_user_filter
    "whodunnit = #{current_user.try(:id)} AND " if current_user.try(:id) && current_user.try(:id).to_i > 0
  end
 
  def add_event_filter (event)
    "event = '#{event}' AND " if event && !(event.eql? 'Any')
  end
 
  def add_date_time_filter
    "created_at >= '#{time_to_string(params[:start_time])}' AND " +
        "created_at <= '#{time_to_string(params[:end_time])}'"
  end
 
  def add_version_type_filter (version_type)
    "item_type = '#{version_type}' AND " if version_type && !(version_type.eql? 'Any')
  end
</pre>
* The paginate method has been moved to the helper class Pagination_Helper. This new method can be now reused by the different components like UsersController etc. The method receives two parameters, first the list to paginate and second the number of items to be displayed in a page.
 
<pre>
module PaginationHelper
 
  def paginate (items, number_of_items_per_page)
    items.page(params[:page]).per_page(number_of_items_per_page)
  end
 
end
</pre>
 
===Code improvements===
* Introduced a constant VERSIONS_PER_PAGE and assigned the value 25 to it. The pagination algorithm for VersionsController displays at most 25 versions in a page. The existing implementation uses the value 25 straight in the code and there are few problems associated with such an approach.
** It is not easy to understand what 25 is unless the programmer takes a close look at the code.
** In case if the value 25 is used at more than one places and in future a new requirement comes to show at most 30 versions in a page, all the values will have to be modified. It is not very DRY.
* The VersionsController was overriding AccessHelper - action_allowed? method to return true in all the cases. This was violating the whole purpose of the method action_allowed?. The purpose of this method is to determine whether the user who is triggering a CRUD operation is allowed to do so. So when the current user invokes a CRUD operation, the action_allowed? method is invoked first and if the method returns true the CRUD operation is triggered or else the user is intimated with a message and gracefully exited. Hence, when the action_allowed? method is overridden to return true always, it results in providing unauthorized access to certain users.
 
<pre>
def action_allowed?
    true
  end
</pre>
 
:With the new implementation the AccessHelper - action_allowed? method has been modified in such a way that unauthorized access is prevented. As per the new algorithm, 'new', 'create', 'edit', 'update' cannot be invoked by any user. These operations can be accessed only by ‘papertrail’ gem. Only an ‘Administrator’ or ‘Super-Administrator’ can call 'destroy_all' method. All the other methods are accessible to ‘Administrator’,  ‘Super-Administrator’, ‘Instructor’, ‘Teaching Assistant’ and ‘Student’.
 
<pre>
  def action_allowed?
    case params[:action]
    when 'new', 'create', 'edit', 'update'
    #Modifications can only be done by papertrail
      return false
    when 'destroy_all'
      ['Super-Administrator',
      'Administrator'].include? current_role_name
    else
      #Allow all others
      ['Super-Administrator',
      'Administrator',
      'Instructor',
      'Teaching Assistant',
      'Student'].include? current_role_name
    end
  end
</pre>
 
===Automated Testing using RSPEC===
The current version of expertiza did not have any test for VersionsController. Using the test driven development(TDD) approach, we have added an exhaustive set of RSPEC tests for VersionsController, to test all the modifications we have done to the code of the controller class. The tests use double and stub features of rspec-rails gem, to fake the log in by different users - Administrator, Instructor, Student etc. The tests can be executed "rpec spec" command as shown below.
<pre>
user-expertiza $rspec spec
.
.
.
Finished in 5.39 seconds (files took 25.33 seconds to load)
66 examples, 0 failures
 
Randomized with seed 19254
.
.
</pre>
 
===Testing from UI===
Following are a few testcases with respectto our code changes that can be tried from UI:
1. To go to versions index page, type in the following url after logging in:
  http://152.46.16.81:3000/versions
 
2. After logging in as student/instructor or admin : Try accessing the  new, create, edit, update actions. These actions are not allowed to any of the users.
  http://152.46.16.81:3000/versions/new
  This calls the new action. In the current production version of expertiza, it is unhandled and application gives a default 404 page.


3. Another feature that can be tested from UI is Pagination. Try searching for a user's versions and see if the results are paginated or not. Search here:
  http://152.46.16.81:3000/versions/search


4. Visit the same URL as step 3, you should see only the students under that instructor in the users dropdown.


===References===
===References===

Revision as of 01:42, 28 October 2017

E1777. OSS Project Green: Coherent specification of review requirements

This page provides a description of the Expertiza based OSS project.



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.

Problem Statement

The following tasks were accomplished in this project:

  • Improved the punctuation, syntax and the capitalization of statements in the review strategy tab.
  • Provided information buttons to elaborate difference between the synonymous statements present in review strategy tab.
  • Handled issue of project submission assignment process to ensure every submission receives required number of reviews.

Current Implementation

Functionality
  • In Expertiza, there are two ways of assigning reviews to reviewers: either the instructor decides who reviews whom (“instructor-selected”), or “auto-selected,” in which case reviews are not assigned until a student seeks to choose something to review. To allow reviewers a larger set of topics to choose from, the instructor can set the threshold (on the Review Strategy tab of assignment creation/editing) to some integer k > 0. Then any submission that has within k reviews of the fewest number can be chosen by a new reviewer. Let’s say that all submissions have at least 1 review. If k = 3, then the reviewer can choose any topic where there is a submission that has 4 or fewer reviews so far. Suppose that the minimum number of reviews for any submission is 2, but that I have reviewed all the submissions that have only 2 reviews. Then I’m not allowed to review at all (unless k > 0).
  • A reviewer does not receive a submission to review, because all the submissions have either fulfilled the review requirements or has already been reviewed by this particular reviewer.
  • The Review Strategy tab includes options, "Set Allowed Number of Reviews per reviewer" and "Set Required Number of Reviews per reviewer."
  • The capitalization and punctuation in the statements ***** under the review strategy tab are random.
  • On the Review Strategy tab of assignment creation, the "Maximum number of reviews per submission" checks the number of reviews that have been assigned to reviewers instead of checking the number of reviews that are submitted by the users. This means that if reviewers choose submissions and don't submit their reviews, those submissions cannot be reviewed by anyone else.
Drawbacks and Solutions
  • Problem 1: The system always allocates to a reviewer, that submission which has received a minimum number of reviews. If a reviewer has already reviewed the submission with the minimum number of reviews and he requests for a new submission to review, he does not receive any submission to review.
* Solution: This issue has been fixed previously. The reviewer will get assigned a submission even if it has fulfilled the required number of reviews, to ensure that the reviewer always receives a new submission to review as long as it is not his own.
  • Problem 2: The two statements "Set Allowed Number of Reviews per reviewer" and "Set Required Number of Reviews per reviewer." are not well differentiated. It can very confusing for an instructor to give values for them.
  • Solution: Information buttons have been provided beside these statements in the review strategy tab to make sure that the instructor knows the difference between the two.
  • Problem 3: The capitalization and punctuations of statements **** are incorrect.
  • Solution: This view has been fixed by making changes in the respective files.


  • The method paginate_list has been split into 2 methods now.
    • BuildSearchCriteria – as the name suggests the sole purpose of this method is to build a search criteria based on the input search filters when the current user initiates a search in versions.
    • paginate_list – this method will call the paginate API.
First the search criteria is built, then the criteria is applied to versions in the database to get all versions which matches the criteria and then the retrieved versions are paginated.


References

  1. Expertiza on GitHub
  2. GitHub Project Repository Fork
  3. The live Expertiza website
  4. Demo link
  5. Expertiza project documentation wiki
  6. Rspec Documentation
  7. Clean Code: A handbook of agile software craftsmanship. Author: Robert C Martin
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