🌿 Farmers Marketplace

A minimal MVP marketplace where farmers list products and buyers pay using the Stellar Network (XLM).

Stack

• Frontend: React + Vite
• Backend: Node.js + Express
• Database: SQLite (local dev, default) / PostgreSQL (production)
• Payments: Stellar Testnet (XLM)

Project Structure

FarmersMarketplace/
├── backend/
│   ├── src/
│   │   ├── index.js          # Express app entry
│   │   ├── stellar.js        # Stellar SDK helpers
│   │   ├── middleware/auth.js
│   │   ├── db/schema.js      # SQLite schema + connection
│   │   └── routes/
│   │       ├── auth.js       # register, login
│   │       ├── products.js   # CRUD listings
│   │       ├── orders.js     # place order + pay
│   │       └── wallet.js     # balance, transactions, fund
│   └── package.json
└── frontend/
    ├── src/
    │   ├── App.jsx
    │   ├── api/client.js     # API wrapper
    │   ├── context/AuthContext.jsx
    │   ├── components/Navbar.jsx
    │   └── pages/
    │       ├── Auth.jsx      # Login + Register
    │       ├── Dashboard.jsx # Farmer: add/view products
    │       ├── Marketplace.jsx # Buyer: browse
    │       ├── ProductDetail.jsx # Buy flow
    │       └── Wallet.jsx    # Balance + transactions
    └── package.json

Quick Start

1. Backend

cd backend
cp .env.example .env
npm install
npm run dev

Runs on http://localhost:4000

2. Frontend

cd frontend
npm install
npm run dev

Runs on http://localhost:3000

Payment Flow

1. Register as a buyer and a farmer (two separate accounts)
2. Go to Wallet → click "Fund with Testnet XLM" (uses Stellar Friendbot, free testnet tokens)
3. As a farmer, go to Dashboard and list a product priced in XLM
4. As a buyer, browse the Marketplace, open a product, set quantity, click Buy Now
5. The backend signs and submits a real Stellar transaction on testnet
6. View the transaction hash in Wallet → Transaction History or on stellar.expert

API Endpoints

Interactive API documentation is available at http://localhost:4000/api/docs when the backend is running.

Method	Path	Auth	Description
POST	/api/auth/register	—	Register user
POST	/api/auth/login	—	Login
GET	/api/products	—	Browse all products
GET	/api/products/:id	—	Product detail
POST	/api/products	farmer	Create listing
GET	/api/products/mine/list	farmer	My listings
DELETE	/api/products/:id	farmer	Remove listing
POST	/api/orders	buyer	Place + pay order
GET	/api/orders	buyer	Order history
GET	/api/orders/sales	farmer	Incoming sales
GET	/api/wallet	auth	Balance
GET	/api/wallet/transactions	auth	TX history
POST	/api/wallet/fund	auth	Fund via Friendbot (testnet)
GET	/api/contracts/:contractId/state?prefix=	auth	View Soroban contract storage entries (JSON: key, val, durability)

Database Migrations

Schema changes are managed through versioned SQL migration files in backend/migrations/.

Running migrations

cd backend
npm run migrate           # apply all pending migrations
npm run migrate:rollback  # revert the last applied migration

Migrations run automatically on app startup — no manual step needed for development.

How it works

• Migration files: backend/migrations/NNN_description.sql
• Rollback files: backend/migrations/NNN_description.undo.sql (optional)
• Applied migrations are tracked in a migrations table in the database
• Running migrate twice is safe — already-applied migrations are skipped

Creating a new migration

# Up migration
echo "ALTER TABLE products ADD COLUMN featured INTEGER DEFAULT 0;" \
  > backend/migrations/002_add_featured.sql

# Rollback (optional)
echo "ALTER TABLE products DROP COLUMN IF EXISTS featured;" \
  > backend/migrations/002_add_featured.undo.sql

npm run migrate

Database Backup and Restore

The application includes automated database backup functionality to protect against data loss.

Manual Backup

Create a timestamped backup of the database:

cd backend
npm run backup

This creates a backup file in backend/backups/ with format market-YYYY-MM-DD.db.

Manual Restore

Restore the database from a backup file:

cd backend
npm run restore -- backups/market-2024-01-01.db

Important: Before restoring, the current database is automatically backed up to market.db.backup.

Automated Daily Backups

• Backups run automatically every day at midnight UTC
• Only the last 7 backups are retained (older ones are automatically deleted)
• Backup status and errors are logged using the structured logging system

Backup Location

• Backup files are stored in: backend/backups/
• File naming convention: market-YYYY-MM-DD.db
• Maximum retention: 7 days

Recovery Procedures

1. Quick Restore: Use npm run restore with the desired backup file
2. Emergency Recovery: Copy market.db.backup (created before restore) back to market.db
3. Complete Reset: Delete market.db and restart the application (fresh schema)

PostgreSQL Setup

The backend supports both SQLite (local dev) and PostgreSQL (production), controlled by the DATABASE_URL environment variable.

Local development (SQLite — default)

No extra setup needed. SQLite is used automatically when DATABASE_URL is not set.

Production (PostgreSQL)

1. Add DATABASE_URL to your .env:

   DATABASE_URL=postgresql://user:password@localhost:5432/farmersmarketplace
   

2. The schema is created automatically on first start.

Docker Compose (PostgreSQL + backend + frontend)

cp backend/.env.example backend/.env
# Edit backend/.env — set JWT_SECRET etc.
docker compose up

This starts:

• postgres — PostgreSQL 16 on port 5432
• backend — Express API on port 4000 (connected to postgres)
• frontend — React app on port 3000

Migrate existing SQLite data to PostgreSQL

DATABASE_URL=postgresql://user:pass@host:5432/dbname \
  node backend/scripts/migrate-sqlite-to-pg.js

Contract Testing (Soroban)

Test Soroban contracts against a local Stellar node using the built-in test harness.

Start the local node

docker-compose -f docker-compose.test.yml up -d

This starts a stellar/quickstart node on port 8000 with Soroban RPC enabled.

Run contract tests

cd backend
npm run test:contracts

Test helpers

backend/src/__tests__/helpers/soroban.js exposes:

• fundAccount(publicKey) — fund via local Friendbot
• deployContract(wasmBuffer, keypair) — upload WASM and create contract instance
• invokeContract(contractId, method, args, keypair) — call a contract function

Environment variables (optional)

Variable	Default	Description
TEST_HORIZON_URL	http://localhost:8000	Local Horizon endpoint
TEST_SOROBAN_RPC_URL	http://localhost:8000/soroban/rpc	Local Soroban RPC
TEST_NETWORK_PASSPHRASE	Standalone Network ; February 2017	Local network passphrase
SKIP_CONTRACT_TESTS	false	Set to true to skip in CI without Docker

Notes

• Stellar wallets are auto-created on registration
• All payments use XLM on Stellar Testnet — no real money involved
• SQLite database file (market.db) is created automatically on first run (when DATABASE_URL is not set)
• To reset SQLite: delete backend/market.db