DigiShop

A mobile marketplace app built with Kivy (Python), backed by a Django REST API and PostgreSQL database. Users can browse products, manage a shopping cart, place orders, and sell their own products — all from a single cross-platform app (desktop or Android APK).

Architecture

[Kivy App (Desktop / APK)] │ HTTPS + JWT ▼

• [Django REST API] ──────► [PostgreSQL (hosted on Render)]
• The Kivy app never talks to the database directly — it only communicates with the Django API over HTTP.
• Authentication is handled with JWT (access + refresh tokens).
• The backend is deployed on Render; the database is a managed PostgreSQL instance also on Render.

Features

• User registration & login (JWT-based)
• Browse products with search and price filters
• Product detail view with quantity selector
• Shopping cart (add / update quantity / remove)
• Checkout — automatically splits an order per seller if the cart contains items from multiple sellers
• Become a seller, add products (with real image upload)
• Sellers can view, edit, and delete their own products
• Sellers can view their incoming orders and update order status (pending / confirmed / shipped / delivered / cancelled) or delete an order

Project Structure

digishop/ ├── main.py # Kivy app entry point ├── requirements.txt # Kivy app dependencies ├── buildozer.spec # Android build configuration │ ├── api/ │ └── client.py # HTTP client, token/session management │ ├── models/ # API-backed data layer (no direct DB access) │ ├── user.py │ ├── product.py │ ├── cart.py │ └── order.py │ ├── ui/ │ ├── app.py # ScreenManager setup │ └── screens/ # One file per screen │ ├── .github/workflows/ │ └── build-apk.yml # CI: builds an Android APK on every push │ └── backend/ # Django REST API project ├── manage.py ├── requirements.txt ├── runtime.txt # Pinned Python version for Render ├── digishop_backend/ # Django project settings ├── accounts/ # User, Customer, Seller + JWT auth ├── products/ # Product CRUD ├── cart/ # Cart management └── orders/ # Order creation & seller order management

Tech Stack

Layer	Technology
Frontend	Python, Kivy
Backend	Django, Django REST Framework
Auth	JWT (djangorestframework-simplejwt)
Database	PostgreSQL
Hosting	Render
Mobile build	Buildozer + GitHub Actions

Setup — Backend

1. Navigate to the backend folder:

   cd backend

2. Install dependencies:

   pip install -r requirements.txt

3. Copy the example config and fill in your own values:

   cp digishop_backend/config.example.py digishop_backend/config.py

4. Run migrations:

   python manage.py migrate

5. Start the development server:

   python manage.py runserver

Setup — Kivy App

1. From the project root, install dependencies:

   pip install -r requirements.txt

2. In api/client.py, set API_BASE_URL to your backend's address (local or deployed).
3. Run the app:

   python main.py

Building the Android APK

Every push to master triggers a GitHub Actions workflow (.github/workflows/build-apk.yml) that builds a debug APK using Buildozer. Once the workflow finishes, download the APK from the Actions tab under that run's artifacts.

Security Notes

• The Kivy app / APK never stores database credentials — it only knows the public API URL.
• Database credentials and the Django secret key are kept in environment variables on Render (or a local config.py, which is git-ignored) — never committed to the repository.
• All protected endpoints require a valid JWT access token.

Known Limitations

• Render's free tier does not provide persistent file storage, so uploaded product images may be cleared on server restarts.
• Sessions are kept in memory only (not persisted to disk), so the app requires a fresh login each time it's restarted.