Weather Agent

┌─────────────────────────────────────────────────────────┐
│                    Weather Agent                         │
├─────────────────────────────────────────────────────────┤
│                                                          │
│  1. Receive request (city name)                          │
│  2. Return 402 Payment Required                          │
│  3. Receive payment (X-Payment header)                   │
│  4. Verify payment via X402Facilitator                   │
│  5. Settle payment on Solana                             │
│  6. Fetch weather data from API                          │
│  7. Return weather information                           │
│                                                          │
└─────────────────────────────────────────────────────────┘

import express from 'express';
import { X402FacilitatorServer } from 'aether-agent-sdk';
import axios from 'axios';

const app = express();
const facilitator = new X402FacilitatorServer();

const WEATHER_PRICE_USDC = 0.01; // $0.01 per request

app.get('/weather/:city', async (req, res) => {
  const { city } = req.params;
  const paymentHeader = req.headers['x-payment'] as string;

  // Payment requirements
  const requirements = {
    scheme: 'exact' as const,
    network: process.env.SOLANA_NETWORK || 'solana-devnet',
    asset: process.env.USDC_MINT!,
    payTo: process.env.MERCHANT_WALLET!,
    maxAmountRequired: String(WEATHER_PRICE_USDC * 1_000_000),
    resource: `/weather/${city}`,
    description: `Weather data for ${city}`,
    maxTimeoutSeconds: 120
  };

  // No payment? Return 402
  if (!paymentHeader) {
    return res.status(402).json({
      error: 'payment_required',
      requirements,
      message: `Weather data costs ${WEATHER_PRICE_USDC} USDC`
    });
  }

  // Verify payment
  const verification = await facilitator.verify(paymentHeader, requirements);

  if (!verification.isValid) {
    return res.status(402).json({
      error: 'payment_invalid',
      reason: verification.invalidReason
    });
  }

  // Settle payment
  const settlement = await facilitator.settle(paymentHeader, requirements);

  if (!settlement.success) {
    return res.status(500).json({
      error: 'settlement_failed',
      reason: settlement.error
    });
  }

  // Fetch weather data
  try {
    const weather = await fetchWeather(city);

    return res.json({
      city,
      weather,
      receipt: {
        txHash: settlement.txHash,
        amount: WEATHER_PRICE_USDC
      }
    });
  } catch (error) {
    return res.status(500).json({ error: 'Failed to fetch weather' });
  }
});

async function fetchWeather(city: string) {
  const apiKey = process.env.OPENWEATHER_API_KEY;
  const response = await axios.get(
    `https://api.openweathermap.org/data/2.5/weather?q=${city}&appid=${apiKey}&units=metric`
  );

  return {
    temperature: response.data.main.temp,
    description: response.data.weather[0].description,
    humidity: response.data.main.humidity,
    wind: response.data.wind.speed
  };
}

app.listen(3000, () => {
  console.log('Weather Agent running on port 3000');
});

import { SettlementAgent } from 'aether-agent-sdk';
import axios from 'axios';

async function getWeather(city: string) {
  const agent = new SettlementAgent();
  await agent.init();

  // First request - get payment requirements
  try {
    await axios.get(`http://localhost:3000/weather/${city}`);
  } catch (error: any) {
    if (error.response?.status === 402) {
      const requirements = error.response.data.requirements;

      // Create payment
      const payment = await agent.createSignedPayment(
        requirements.payTo,
        Number(requirements.maxAmountRequired) / 1_000_000
      );

      // Retry with payment
      const response = await axios.get(
        `http://localhost:3000/weather/${city}`,
        { headers: { 'X-Payment': payment } }
      );

      console.log('Weather:', response.data.weather);
      console.log('Transaction:', response.data.receipt.txHash);
    }
  }
}

getWeather('Paris');

# Install dependencies
npm install

# Start the agent
npm run start

# Test with curl
curl http://localhost:3000/weather/Paris
# Returns 402 with payment requirements

# Test with a paying client
npm run client Paris