Add Python REST API example for Pyth price feeds

- Flask-based REST API supporting 20+ cryptocurrencies
- Real-time price monitoring using Pyth Network's Hermes API
- Threshold checking with boolean results
- Session-based continuous monitoring
- Complete API with 8 endpoints
- Includes tests and documentation

Author: Shivam Kumar

price_feeds/python-rest-api/README.md

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+# Python REST API for Pyth Price Feeds
+
+A Flask-based REST API for monitoring cryptocurrency prices using Pyth Network's decentralized oracle. This example demonstrates how to build a production-ready API with Pyth price feeds, supporting 20+ tokens including BTC, ETH, SOL, and more.
+
+## Features
+
+- ✅ **20+ Cryptocurrencies** - Monitor BTC, ETH, SOL, BNB, AVAX, MATIC, ARB, OP, and more
+- ✅ **Threshold Monitoring** - Check if prices cross specific thresholds
+- ✅ **Real-time Prices** - Powered by Pyth Network's Hermes API
+- ✅ **Session Management** - Monitor multiple tokens simultaneously
+- ✅ **RESTful API** - Clean, well-documented endpoints
+- ✅ **CORS Enabled** - Ready for web applications
+
+## Quick Start
+
+### 1. Install Dependencies
+
+```bash
+pip install -r requirements.txt
+```
+
+### 2. Start the Server
+
+```bash
+python app.py
+```
+
+Server will start on `http://localhost:8080`
+
+### 3. Test the API
+
+```bash
+# In another terminal
+python test_endpoints.py
+```
+
+## API Endpoints
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/health` | GET | Health check |
+| `/api/tokens` | GET | List all supported tokens |
+| `/api/price/<symbol>` | GET | Get current price for any token |
+| `/api/check` | POST | Check price vs threshold (single) |
+| `/api/monitor/start` | POST | Start monitoring session |
+| `/api/monitor/<session_id>` | GET | Get session status |
+| `/api/monitor/<session_id>/stop` | POST | Stop monitoring session |
+| `/api/monitor/sessions` | GET | List all sessions |
+
+## Usage Examples
+
+### Get Bitcoin Price
+
+```bash
+curl http://localhost:8080/api/price/BTC/USD
+```
+
+**Response:**
+```json
+{
+  "success": true,
+  "symbol": "BTC/USD",
+  "price": 67234.56,
+  "timestamp": "2024-01-23T10:15:23.123456"
+}
+```
+
+### Check if ETH is Below $3000
+
+```bash
+curl -X POST http://localhost:8080/api/check \
+  -H "Content-Type: application/json" \
+  -d '{"symbol": "ETH/USD", "threshold": 3000}'
+```
+
+**Response:**
+```json
+{
+  "success": true,
+  "symbol": "ETH/USD",
+  "price": 2845.67,
+  "threshold": 3000,
+  "is_below_threshold": true,
+  "result": true,
+  "timestamp": "2024-01-23T10:15:23.123456"
+}
+```
+
+### Start Continuous Monitoring
+
+```bash
+curl -X POST http://localhost:8080/api/monitor/start \
+  -H "Content-Type: application/json" \
+  -d '{
+    "symbol": "BTC/USD",
+    "threshold": 50000,
+    "update_interval": 10
+  }'
+```
+
+**Response:**
+```json
+{
+  "success": true,
+  "message": "Started monitoring BTC/USD with threshold $50000.00",
+  "session_id": "session_1",
+  "symbol": "BTC/USD",
+  "threshold": 50000,
+  "update_interval": 10
+}
+```
+
+## Supported Tokens
+
+BTC/USD, ETH/USD, SOL/USD, BNB/USD, AVAX/USD, MATIC/USD, ARB/USD, OP/USD, DOGE/USD, ADA/USD, DOT/USD, LINK/USD, UNI/USD, ATOM/USD, XRP/USD, LTC/USD, APT/USD, SUI/USD, TRX/USD, NEAR/USD
+
+Get the complete list:
+```bash
+curl http://localhost:8080/api/tokens
+```
+
+## Project Structure
+
+```
+python-rest-api/
+├── app.py                # Flask REST API server
+├── price_monitor.py      # Core price monitoring logic
+├── requirements.txt      # Python dependencies
+├── test_endpoints.py     # API test suite
+└── README.md            # This file
+```
+
+## Key Components
+
+### price_monitor.py
+
+Core module that handles Pyth Network integration:
+- Fetches prices from Pyth's Hermes API
+- Supports 20+ cryptocurrency pairs
+- Provides both single-check and continuous monitoring
+- Handles price threshold comparisons
+
+### app.py
+
+Flask REST API server that provides:
+- RESTful endpoints for price queries
+- Session-based continuous monitoring
+- Background threading for real-time updates
+- CORS support for web applications
+
+## Python Client Example
+
+```python
+import requests
+import time
+
+BASE_URL = "http://localhost:8080"
+
+# Get current price
+response = requests.get(f"{BASE_URL}/api/price/BTC/USD")
+price_data = response.json()
+print(f"BTC Price: ${price_data['price']:,.2f}")
+
+# Quick threshold check
+response = requests.post(f"{BASE_URL}/api/check", json={
+    "symbol": "ETH/USD",
+    "threshold": 3000
+})
+result = response.json()
+print(f"ETH below $3000: {result['is_below_threshold']}")
+
+# Start monitoring
+response = requests.post(f"{BASE_URL}/api/monitor/start", json={
+    "symbol": "BTC/USD",
+    "threshold": 50000,
+    "update_interval": 10
+})
+session_id = response.json()['session_id']
+print(f"Started monitoring, session: {session_id}")
+
+# Poll for updates
+try:
+    while True:
+        response = requests.get(f"{BASE_URL}/api/monitor/{session_id}")
+        data = response.json()['data']
+        
+        if data['price']:
+            print(f"[{data['timestamp']}] {data['symbol']}: "
+                  f"${data['price']:,.2f} | Below threshold: {data['is_below_threshold']}")
+        
+        time.sleep(10)
+except KeyboardInterrupt:
+    # Stop monitoring
+    requests.post(f"{BASE_URL}/api/monitor/{session_id}/stop")
+    print("\nMonitoring stopped")
+```
+
+## Use Cases
+
+- **Price Alerts** - Build notification systems for price thresholds
+- **Trading Bots** - Integrate real-time price data for automated trading
+- **Portfolio Tracking** - Monitor multiple assets simultaneously
+- **Market Analysis** - Collect and analyze price trends
+- **DeFi Integrations** - Use as a data feed for decentralized applications
+
+## Technologies
+
+- **Flask** - Lightweight web framework
+- **Pyth Network** - Decentralized oracle for real-time price data
+- **Python 3.7+** - Programming language
+- **Threading** - For concurrent monitoring sessions
+
+## Deployment
+
+This API can be easily deployed using:
+- **ngrok** - For quick public exposure (see deployment guide)
+- **Docker** - Containerized deployment
+- **Cloud Services** - AWS, GCP, Azure, Heroku, etc.
+
+## About Pyth Network
+
+This example uses [Pyth Network](https://pyth.network)'s Hermes API to fetch real-time cryptocurrency prices. Pyth Network is a decentralized oracle that provides high-fidelity, high-frequency market data from over 90+ first-party publishers.
+
+## License
+
+Apache 2.0
+
+---
+
+**Built with [Pyth Network](https://pyth.network) 🔮**
+