Delivery Order Price Calculator

This is a FastAPI-based application that calculates delivery order prices, including delivery fees and small order surcharges, based on venue and user location details. The application fetches venue data from an external API and calculates distances using the Haversine formula.

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Features

• Calculate total delivery order price.
• Includes delivery fees, small order surcharges, and cart value.
• Uses FastAPI for a robust and fast web framework.
• Validates requests and responses using Pydantic models.
• Fetches external venue data for dynamic calculations.

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Prerequisites

• Python 3.10 or higher.
• Virtual environment for dependency management.

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Installation

1. Clone the repository:

   git clone <repository-url>
   cd <repository-folder>

2. Create and activate a virtual environment:

   python -m venv venv
   source venv/bin/activate  # On Windows: venv\Scripts\activate

3. Install the required dependencies:

   pip install -r requirements.txt

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Running the Application

1. Navigate to the project directory:

   cd <repository-folder>

2. Start the FastAPI application using Uvicorn:

   uvicorn app.main:app --reload

3. Access the application in your browser or API client:

   • Swagger UI: http://127.0.0.1:8000/docs
   • ReDoc Documentation: http://127.0.0.1:8000/redoc
   • Root Endpoint: http://127.0.0.1:8000/

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API Usage

Endpoint

GET /api/v1/delivery-order-price

Query Parameters

Parameter	Type	Description	Example
venue_slug	string	Unique identifier for the venue	home-assignment-venue-helsinki
cart_value	integer	Total value of items in the cart	1000
user_lat	float	Latitude of the user's location	60.17094
user_lon	float	Longitude of the user's location	24.93087

Example Request

curl "http://localhost:8000/api/v1/delivery-order-price?venue_slug=home-assignment-venue-helsinki&cart_value=1000&user_lat=60.17094&user_lon=24.93087"

Example Response

{
  "total_price": 1190,
  "small_order_surcharge": 0,
  "cart_value": 1000,
  "delivery": {
    "fee": 190,
    "distance": 177
  }
}

Valid venue slug

Finland: home-assignment-venue-helsinki

Sweden: home-assignment-venue-stockholm

Germany: home-assignment-venue-berlin

Japan: home-assignment-venue-tokyo

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Project Structure

project-folder/
├── app/
│   ├── main.py               # FastAPI entry point
│   ├── config.py             # Configuration settings
│   ├── routers/
│   │   ├── delivery.py       # API routes for delivery calculations
│   ├── services/
│   │   ├── venue_service.py  # Handles external API requests
│   ├── utils/
│       ├── delivery_calculations.py  # Delivery logic
├── tests/
│   ├── test_delivery.py      # Unit tests
├── requirements.txt          # Dependencies
├── README.md                 # Project documentation

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Testing

1. Install pytest if not already installed:

   pip install pytest

2. Run the tests:

   pytest

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Improvements

Future improvements could include:

• Adding caching for external API calls.
• Implementing advanced error logging.
• Integrating with a database for persistent storage.
• Adding more comprehensive test cases.