Splitwise - Expense Tracker System

Overview

Splitwise project is an example Flask web application designed to manage expenses among users. This README provides an overview of the project structure and how to run the application.

Directory Structure

splitwise/
├── db.sqlite3
├── manage.py
├── splitwise/
│   ├── __init__.py
│   ├── settings.py
│   ├── urls.py
│   └── wsgi.py
├── divvy/
│   ├── migrations/
│   │   └── __init__.py
│   ├── __init__.py
│   ├── admin.py
│   ├── apps.py
│   ├── models.py
│   ├── serializers.py
│   ├── tests.py
│   └── views.py
├── templates/
│   └── index.html
└── Backend Programming Assignment - Splitwise Indore.pdf

Project Structure

• The splitwise/ directory serves as the root directory of the Django project.

  • manage.py: A command-line utility for managing the project.

  • splitwise/: The main Django app for the Splitwise project.

    • __init__.py: Marks the directory as a Python package.

    • settings.py: Contains project settings and configurations.

    • urls.py: Defines URL patterns for routing requests to views.

    • wsgi.py: Entry point for WSGI-compatible web servers.

  • divvy/: A secondary app within the project, possibly handling expense-related functionalities.

    • migrations/: Contains database migration files.

    • __init__.py, admin.py, apps.py, models.py, serializers.py, tests.py, views.py: Standard Django files for defining models, views, serializers, tests, etc.

  • templates/: Directory containing HTML templates for rendering views.

This structure organizes the project's files and directories according to Django conventions, facilitating easy management and navigation.

Getting Started

To set up and run the Django project with Django REST Framework:

1. Install Django and Django REST Framework:

   pip install django djangorestframework

2. Navigate to the project directory:

   cd splitwise/

3. Apply database migrations:

   python manage.py migrate

4. Start the development server:

   python manage.py runserver

5. Access the application at http://localhost:8000/.

6. (Optional) Create a superuser to access the Django admin panel:

   python manage.py createsuperuser

   Follow the prompts to create a username, email, and password.

Now you're ready to use the Splitwise Django application with Django REST Framework!

Class Diagram

+------------------+       +-------------------+       +---------------------+       +---------------------+
|       User       |       |      Expense      |       |   ExpensePaidBy     |       |   ExpenseOwedBy     |
+------------------+       +-------------------+       +---------------------+       +---------------------+
| - userId (PK)    |       | - expenseId (PK)  |       | - userId (FK)       |       | - userId (FK)       |
| - name           |       | - desc            |       | - expenseId (FK)    |       | - expenseId (FK)    |
| - email          |       | - amount          |       | - amountPaid        |       | - amountOwed        |
| - mobileNumber   |       | - createdById (FK)|       +---------------------+       +---------------------+
+------------------+       | - createdAt       |       
                           +-------------------+

User Class

• userId
• name
• email
• mobileNumber

Expense Class

• expenseId
• desc
• amount
• createdById
• createdAt

ExpensePaidBy Class

• userId
• expenseId
• amount

ExpenseOwedBy Class

• userId
• expenseId
• amount

Database Model

User

• userId: Integer (Primary Key)
• name: String (255), Not Null
• email: String (255), Unique, Not Null
• mobileNumber: String (20), Not Null

Expense

• expenseId: Integer (Primary Key)
• desc: String (255), Not Null
• amount: Decimal (15, 2), Not Null
• createdById: Integer, Not Null
• createdAt: Timestamp, Default: Current Timestamp

ExpensePaidBy

• userId: Integer (Foreign Key to User.userId, Primary Key)
• expenseId: Integer (Foreign Key to Expense.expenseId, Primary Key)
• amount: Decimal (15, 2), Not Null

ExpenseOwedBy

• userId: Integer (Foreign Key to User.userId, Primary Key)
• expenseId: Integer (Foreign Key to Expense.expenseId, Primary Key)
• amount: Decimal (15, 2), Not Null

Entity Descriptions

User

• userId: Unique identifier for each user.
• name: Name of the user.
• email: Email address of the user.
• mobileNumber: Mobile number of the user.

Expense

• expenseId: Unique identifier for each expense.
• desc: Description of the expense.
• amount: Total amount of the expense.
• createdById: User ID of the creator of the expense. Default: userId = 1
• createdAt: Timestamp indicating when the expense was created.

ExpensePaidBy

• user: User who paid for the expense.
• expense: Expense for which the user made a payment.
• amountPaid: Amount paid by the user for the expense.

ExpenseOwedBy

• user: User who owes money for the expense.
• expense: Expense for which the user owes money.
• amountOwed: Amount owed by the user for the expense.

Relationships

• The User entity is associated with the UserExpensePaid and UserExpenseOwed entities.
• The Expense entity is associated with the UserExpensePaid and UserExpenseOwed entities.

Splitwise API Documentation

1. Get Users

• Endpoint: /users
• Method: GET
• Description: Retrieves a list of all users.
• Response Format:

  {
  "users": [
      {
      "userId": 1,
      "name": "John Doe",
      "email": "[email protected]",
      "mobileNumber": "123-456-7890"
      },
      // Additional user objects...
  ]
  }

2. Add User

• Endpoint: /add_user
• Method: POST
• Description: Adds a new user to the system.
• Request Format:

  {
  "name": "John Doe",
  "email": "[email protected]",
  "mobileNumber": "123-456-7890"
  }

• Response Format:

  {
  "message": "User added successfully"
  }

3. Add Expense

Equal Split

• Endpoint: /add_expense
• Method: POST
• Description: Adds a new expense along with expense-related details.
• Request Format:

  {
  "expense_type": "EQUAL",
  "desc": "electricity bill",
  "total_amount": 500,
  "paidBy": {
      "2": 200,
      "3": 300
  }
  }

• Response Format:

  {
  "message": "Expense split equally added successfully"  // or details of any errors
  }

Exact Split

• Endpoint: /add_expense
• Method: POST
• Description: Adds a new expense along with expense-related details.
• Request Format:

  {
  "expense_type": "EXACT",
  "desc": "paytm",
  "total_amount": 600,
  "paidBy": {
      "1": 300,
      "3": 300
  },
  "owedBy": {
      "1": 100,
      "3": 200,
      "4": 300
  }
  }

• Response Format:

  {
  "message": "Expense split exactly added successfully"  // or details of any errors
  }

Percent Split

• Endpoint: /add_expense

• Method: POST

• Description: Adds a new expense along with expense-related details.

• Request Format:

  {
  "expense_type": "PERCENT",
  "desc": "paytm",
  "total_amount": 700,
  "paidBy": {
      "1": 700
  },
  "owedBy": {
      "1": 20,
      "2": 33,
      "3": 47
  }
  }

• Response Format:

  {
  "message": "Expense split by percentage added successfully"  // or details of any errors
  }