Contents

• Intro
• Models
• Views
  • Authentication
  • Permissions
  • Mixins
  • Cache
  • Endpoints
• Crud

Run

• Run from docker-compose

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Intro

The project is initialized by a Django Command common/management/commands/mock_users_and_projects.py, this command creates 15 users from user_1 to user_15 with password Passw0rd! and an admin user with username admin and password Passw0rd!.

It also creates 3 project instances assigning users as follow:

• proj1 --> user_1, user_2, user_3, user_4, user_5
• proj2 --> user_6, user_7, user_8, user_9, user_10
• proj3 --> no user
• no project --> user_11, user_12, user_13, user_14, user_15

Rest Framework serializers are used only to serialize object and to check validity for input data. Validation in general is inside the models clean method and on models constraints.

Access to database is done by crud modules, so that Views can access to DB only through crud modules.

Main business logic is done in core or in permissions modules.

Models

• common/models:BaseModel

  Abstract model to handle common columns

• projects/models:Project

  General infos about the project, has both a 1to1 relation with UserCustom model as creator and a M2M relation as assignees

• projects/models:ProjectAssignment

  Bridge table for M2M relation Project-UserCustom, it has a unique_toghether constraint so that one user can be assigned to one project only once.

• time_log/models:TimeLog

  Keeps track of working time per user and per project, so it has a M21 relation with ProjectAssignment table both for user and project. The end_time field is null when a user is currently working on some project. It has a constraint to check that end_time is greater than start_time and performs additional validation in the clean method to ensure that two instance of time_log per same user and same project don't overlap.

• users/models:UserCustom

  Simply inherits from Django default AbstractUser model.

Views

Authentication

It is Session based authentication on top of all views and it is handled by REST_FRAMEWORK Basic Authentication and SessionAuthentication DEFAULT_AUTHENTICATION_CLASSES

Permissions

As a general rule, Admin user can do any operation, so next consideration are applied only to standard users. All classes inherits from rest_framework.permissions.BasePermissions overriding, as needed, has_permission and has_object_permissions method

• common/permissions:IsAssignedToProjectOrAdmin

  Checks that a user is access project or time_log information of only assigned projects

• common/permissions:IsLogOwnerOrAdmin

  Inherits from the previous and ensure that a time_log object can only be read by users that are part of the projects and can only be written by user who logged the specific object

• common/permissions:IsAdminForWriting

  Inherits from rest_framework.permissions.IsAdminUser to ensure that specic view is accessed by non admin users only for reading operations.

Mixins

All custom mixins implements the initial method of rest_framework.views.APIView mostly to inject in the view kwargs a specific object or to ensure that a required query parameter was provided

• common/mixins:ObjectFromIdMixin

  Base class that based on field lookup_name searches in the request kwargs the key to be used to search in the crud_instance field so that it can injects the specifc object in the request context using the injection_name. Optionally it can be defined as required so that if it is not found it will raise a ParseError exception

• projects/mixins:ProjectFromIdMixin

  Subclass of base ObjectFromIdMixin

• projects/mixins:ProjectIdQueryStringMixin

  Subclass of ProjectFromIdMixin ensures the ?project_id=_ is passed as query param

• time_log/mixins:TimeLogFromIdMixin

  Subclass of base ObjectFromIdMixin

• users/mixins:UserIdQueryStringMixin

  Takes user from optional ?user_id=_ query param

Cache

Is implemented with a Redis container, it caches the GET views at high level

Endpoints

• projects/views:ProjectListCreateApi

  /projects/

  GET

  Returns the list of projects per user (admin sees them all)

  POST

  Creates a project (only admin)

  body

  {
      "name": "proj_test",
      "description": "my test proj"
  }

• projects/views:ProjectRetrieveUpdateDelete

  /projects/<id>

  GET

  Read a project instance, if assigned to user (admin sees them all)

  PUT

  Edit a project (only admin)

  body

  {
      "name": "proj_test_edit",
      "description": "my test proj edited"
  }

  DELETE

  Delete a project (only admin)

• projects/views:ProjectHandleUsers

  /projects/<id>/handle_users

  POST

  Assign a list of users to a project (only admin)

  body

  [
      "user_7",
      "user_8"
  ]

  DELETE

  Remove a list of users to a project (only admin)

  body

  [
      "user_7"
  ]

• projects/views:ProjectStatistics

  /projects/<id>/statistics[?user_id=1]

  GET

  Total time spent on the given project from all assignees.

  query param (optional)

  ?user_id=1

  To see only time spent by a given user

• time_log/views:TimeLogListCreateApi

  /time_log/project_id=1

  GET

  Returns the list of time_log per user (admin sees them all)

  query param (required)

  ?project_id=1

  To indicate for which project get the logs

  POST

  Creates a time_log if user belongs to ?project_id project

  body

  {
      "start_time": "2022-12-23T12:41:52Z",
      "end_time": "2022-12-23T12:41:53Z"
  }

  query param (required)

  ?project_id=1

  To indicate for which project create the logs

• time_log/views:TimeLogRetrieveUpdateDelete

  /time_log/<id>

  GET

  Read a time_log instance, if user is assigned to project (admin sees them all)

  PUT

  Edit a time_log if user was the logger (admin edits them all)

  body

  {
      "name": "proj_test_edit",
      "description": "my test proj edited"
  }

  DELETE

  Delete a time_log if user was the logger (admin deletes them all)

Crud

In this module there are the classes that access to Database. All classes inherit from common/crud:BaseCRUD that implements some basic methods.

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Run from docker-compose

The Django server is exposed on port 7777

docker-compose up

To run tests, from a different terminal run

docker exec ptt_backend python project_time_tracker/manage.py test tests     

To run again the init command, run

docker exec ptt_backend python project_time_tracker/manage.py mock_users_and_projects