Image Processing API

A Flask-based backend API for user-authenticated image uploads and processing. This API allows users to register/login, upload images, and retrieve processed results (grayscale + resize). It also uses Celery workers with Redis to handle background tasks and cleanup of old files.

Features

• User registration and login with JWT authentication
• Upload images (PNG, JPG, JPEG, GIF)
• Image processing pipeline: converts to grayscale and resizes to 800x600
• Background processing with Celery and Redis (optional synchronous mode for development)
• Automatic cleanup of old image files
• Health check endpoint

Tech Stack

• Python 3.11
• Flask + Flask-JWT-Extended
• SQLAlchemy (DeclarativeBase)
• Marshmallow for validation
• Pillow (PIL) for image processing
• Celery + Redis for asynchronous tasks
• Pytest for testing

Setup Instructions

1. Clone the repository

git clone <your-repo-url>.git
cd ImageProcessingAPI

2. Create a virtual environment and install dependencies

python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate
pip install -r requirements.txt

3. Set environment variables (or create a .env file)

export SECRET_KEY="your-secret-key"
export JWT_SECRET_KEY="your-jwt-secret-key"
export DATABASE_URL="sqlite:///image_processor.db"
export CELERY_BROKER_URL="redis://localhost:6379/0"
export CELERY_RESULT_BACKEND="redis://localhost:6379/0"

4. Run the Flask app

python app.py

The app will run on http://127.0.0.1:5000.

5. Run Celery worker (optional)

celery -A celery_app.celery worker --loglevel=info

6. Run tests locally

pytest -q

API Endpoints

Health Check

GET /health
Returns status of the API and DB connection.

Auth

• POST /api/register -- Register new user
  JSON: { "name": "username", "password": "password" }

• POST /api/login -- Login user
  JSON: { "name": "username", "password": "password" }

Both return JWT access token.

Images

• POST /api/upload (auth required) -- Upload and process an image (multipart/form-data)
• GET /api/images (auth required) -- List user's images
• GET /api/images/<image_id> (auth required) -- Get status of an image
• GET /api/images/<image_id>/result (auth required) -- Download processed image

Running with Docker

This repository can be containerized. Example Dockerfile and .dockerignore can be added. Build the image:

docker build -t image-processing-api .
docker run -p 5000:5000 image-processing-api

To run Celery and Redis together, use docker-compose.yml (recommended).

Testing

Pytest tests are included in the tests/ folder. Run locally before building your image:

pytest -q

Tests include:

• User registration/login
• Image upload and status retrieval
• Model serialization
• Utility methods

License

MIT License (or your chosen license)