@monopay/middleware A lightweight JavaScript middleware for protecting routes with MonoPay payment verification. Easily integrate Solana-based payments into your Node.js/Next.js application.

Installation bash npm install @monopay/middleware

or

yarn add @monopay/middleware

or

pnpm add @monopay/middleware Quick Start Setup in Next.js Create a middleware file at middleware.js in your project root:

javascript import { createMonoPayMiddleware } from "@monopay/middleware"; import { NextResponse } from "next/server";

const monoPayMiddleware = createMonoPayMiddleware(process.env.MONOPAY_API_KEY);

export async function middleware(request) { const response = await monoPayMiddleware(request);

if (response.status === 402) { return response; }

if (response.status === 401 || response.status === 403 || response.status === 500) { return response; }

return NextResponse.next(); }

export const config = { matcher: ["/api/protected/:path*"], }; Setup in Express javascript const express = require("express"); const { createMonoPayMiddleware } = require("@monopay/middleware");

const app = express(); const monoPayMiddleware = createMonoPayMiddleware(process.env.MONOPAY_API_KEY);

app.use("/api/protected", async (req, res, next) => { const request = new Request(http://localhost:${req.socket.remoteAddress}${req.url}, { method: req.method, headers: req.headers, });

const response = await monoPayMiddleware(request);

if (response.status === 402) { const data = await response.json(); return res.status(402).json(data); }

if (!response.ok) { const data = await response.json(); return res.status(response.status).json(data); }

next(); });

app.listen(3000); Environment Variables Create a .env.local file:

env MONOPAY_API_KEY=your_api_key_here MONOPAY_HOST_API=https://api.monopay.xyz # Optional, uses default if omitted API Reference createMonoPayMiddleware(apiKey, hostApi?) Creates a middleware function that validates MonoPay payments.

Parameters:

apiKey (string): Your MonoPay API key hostApi (string, optional): Custom MonoPay host API URL Returns: Middleware function that processes requests

Example:

javascript const middleware = createMonoPayMiddleware( process.env.MONOPAY_API_KEY, "https://custom-api.monopay.xyz" ); verifyPayment(txSignature, serviceId, payoutWallet, priceLamports, hostApi?) Manually verify a payment signature.

Parameters:

txSignature (string): Transaction signature serviceId (string): Your service ID payoutWallet (string): Payout wallet address priceLamports (number): Price in lamports hostApi (string, optional): Custom API URL Returns: Promise

Example:

javascript const { verifyPayment } = require("@monopay/middleware");

const result = await verifyPayment( "tx_signature_here", "service_123", "wallet_address", 5000000 );

if (result.success) { console.log("Payment verified!"); } Caching The middleware automatically caches service configurations for 5 minutes internally to reduce API calls. This is handled transparently - no action needed from you.

Response Types Payment Required (402) javascript { requiresPayment: true, serviceId: "string", wallet: "string", priceLamports: 5000000, message: "Payment required for this route" } Success (200) Route access granted after payment verification.

Errors 401: Invalid API key 403: Invalid payment 500: Internal server error Examples Basic Usage javascript const { createMonoPayMiddleware } = require("@monopay/middleware");

const middleware = createMonoPayMiddleware(process.env.MONOPAY_API_KEY);

// Use in your request handler const response = await middleware(request);

if (response.status === 402) { // Handle payment required const paymentData = await response.json(); console.log("Payment required:", paymentData); } Manual Verification javascript const { verifyPayment } = require("@monopay/middleware");

async function handlePayment(req, res) { const txSig = req.headers["x-tx-signature"];

const result = await verifyPayment( txSig, config.serviceId, config.payoutWallet, config.priceLamports );

if (!result.success) { return res.status(403).json({ error: "Payment invalid" }); }

// Process the request res.json({ success: true }); } With API Route Handler javascript import { createMonoPayMiddleware } from "@monopay/middleware";

const monoPayMiddleware = createMonoPayMiddleware(process.env.MONOPAY_API_KEY);

export default async function handler(req, res) { const response = await monoPayMiddleware(req);

if (response.status === 402) { const data = await response.json(); return res.status(402).json(data); }

if (!response.ok) { const data = await response.json(); return res.status(response.status).json(data); }

// Your protected logic here res.json({ data: "Protected content" }); } Usage javascript const { createMonoPayMiddleware, verifyPayment } = require("@monopay/middleware"); Error Handling All errors are caught and logged. Common scenarios:

Invalid API Key: Returns 401 status Missing Payment Signature: Returns 402 with payment details Payment Verification Failed: Returns 403 Network/Server Error: Returns 500 Project Structure monopay-middleware/ ├── src/ │ ├── index.js # Main middleware and utilities │ ├── cache.js # Caching logic │ └── package.json ├── README.md └── .gitignore Publishing to NPM bash

1. Login to npm

npm login

2. Update version in package.json

npm version patch # or minor/major

3. Publish

npm publish License MIT

Support For issues and questions, visit GitHub Issues