edgeone-makers-middleware

Middleware

Lightweight request interception running at the edge (V8 runtime). Use for redirects, rewrites, auth guards, A/B testing, and header injection.

⚠️ Framework projects (Next.js, Nuxt, etc.): Do NOT use this platform middleware format. Use the framework's built-in middleware instead (e.g. Next.js middleware.ts with NextRequest/NextResponse). The patterns below are for non-framework or pure static projects only.

Basic middleware

File: middleware.js (project root)

export function middleware(context) {
  const { request, next, redirect, rewrite } = context;

  // Pass through — no modification
  return next();
}

Context API

Property	Type	Description
request	Request	Current request object
next(options?)	Function	Continue to origin; optionally modify headers
redirect(url, status?)	Function	Redirect (default 307)
rewrite(url)	Function	Rewrite request path (transparent to client)
geo	GeoProperties	Client geolocation
clientIp	string	Client IP address

Route matching

By default middleware runs on ALL routes. Use config.matcher to limit scope:

// Only run on /api/* routes
export const config = {
  matcher: ['/api/:path*'],
};

export function middleware(context) {
  // Auth check for API routes only
  const token = context.request.headers.get('Authorization');
  if (!token) {
    return new Response('Unauthorized', { status: 401 });
  }
  return context.next();
}

Matcher patterns:

// Single path
export const config = { matcher: '/about' };

// Multiple paths
export const config = { matcher: ['/api/:path*', '/admin/:path*'] };

// Regex
export const config = { matcher: ['/api/.*', '^/user/\\d+$'] };

Common patterns

URL Redirect

export function middleware(context) {
  const url = new URL(context.request.url);

  if (url.pathname === '/old-page') {
    return context.redirect('/new-page', 301);
  }
  return context.next();
}

URL Rewrite (transparent proxy)

export function middleware(context) {
  const url = new URL(context.request.url);

  if (url.pathname.startsWith('/blog')) {
    return context.rewrite('/content' + url.pathname);
  }
  return context.next();
}

Add request headers

export function middleware(context) {
  return context.next({
    headers: {
      'x-request-id': crypto.randomUUID(),
      'x-client-ip': context.clientIp,
      'x-country': context.geo.countryCodeAlpha2,
    },
  });
}

Auth guard

export const config = {
  matcher: ['/api/:path*', '/admin/:path*'],
};

export function middleware(context) {
  const token = context.request.headers.get('Authorization');
  if (!token || !token.startsWith('Bearer ')) {
    return new Response(JSON.stringify({ error: 'Unauthorized' }), {
      status: 401,
      headers: { 'Content-Type': 'application/json' },
    });
  }
  return context.next();
}

Geo-based routing

export function middleware(context) {
  const country = context.geo.countryCodeAlpha2;

  if (country === 'CN') {
    return context.rewrite('/zh' + new URL(context.request.url).pathname);
  }
  return context.next();
}

A/B Testing

export function middleware(context) {
  const url = new URL(context.request.url);

  if (url.pathname === '/landing') {
    const variant = Math.random() < 0.5 ? '/landing-a' : '/landing-b';
    return context.rewrite(variant);
  }
  return context.next();
}

Direct JSON response

export function middleware(context) {
  const url = new URL(context.request.url);

  if (url.pathname === '/api/health') {
    return new Response(JSON.stringify({ status: 'ok', timestamp: Date.now() }), {
      headers: { 'Content-Type': 'application/json' },
    });
  }
  return context.next();
}

GeoProperties

Available on context.geo:

Property	Type	Example
countryName	string	Singapore
countryCodeAlpha2	string	SG
countryCodeAlpha3	string	SGP
regionName	string	—
cityName	string	Singapore
latitude	number	1.29027
longitude	number	103.851959
asn	number	132203