school_compare/nextjs-app/next.config.mjs

/** @type {import('next').NextConfig} */
const nextConfig = {
  // Enable standalone output for Docker
  output: 'standalone',

  // app/opengraph-image.tsx reads the Schibsted Grotesk files off disk at
  // request time (Satori needs a font buffer; it has no system fallback).
  // File tracing currently picks these up on its own, but that relies on the
  // tracer resolving a runtime join() — declare them so a Next upgrade can't
  // silently drop them and turn every link preview into a 500.
  outputFileTracingIncludes: {
    '/opengraph-image': ['./assets/**'],
  },

  // The /api/* and /sitemap.xml proxies to the FastAPI backend are route
  // handlers (app/api/[...path]/route.ts, app/sitemap.xml/route.ts) rather
  // than rewrites, so the backend host is read from FASTAPI_URL at runtime
  // instead of being baked into the build.

  // Image optimization
  images: {
    remotePatterns: [
      { protocol: 'https', hostname: '*.tile.openstreetmap.org' },
      { protocol: 'https', hostname: 'tile.openstreetmap.org' },
      { protocol: 'https', hostname: 'cdnjs.cloudflare.com' },
    ],
    formats: ['image/avif', 'image/webp'],
    minimumCacheTTL: 31536000,
  },

  // Performance optimizations
  compiler: {
    // Remove console logs in production
    removeConsole: process.env.NODE_ENV === 'production',
  },

  // Compression
  compress: true,

  // React strict mode for better error detection
  reactStrictMode: true,

  // Power optimizations
  poweredByHeader: false,

  // Production source maps (disable for smaller bundles)
  productionBrowserSourceMaps: false,

  // Experimental features for performance
  experimental: {
    // Optimize package imports
    optimizePackageImports: ['chart.js', 'react-chartjs-2', 'leaflet'],
  },

  // Headers for caching and security
  async headers() {
    return [
      {
        /*
         * Keep non-production hosts out of the index.
         *
         * Staging serves the same image as production off stx., so without
         * this it is a full crawlable duplicate of the site.
         *
         * X-Robots-Tag, NOT a robots.txt Disallow. Disallow blocks crawling,
         * which is not the same as blocking indexing — a disallowed URL can
         * still be indexed from external links, and worse, blocking the crawl
         * means Google never fetches the page and never sees a noindex at all.
         * Staging therefore stays crawlable and answers "noindex" when crawled.
         *
         * Matched on the staging host explicitly rather than "any host that is
         * not production". The inverted form is tempting because it would cover
         * future environments automatically, but its failure mode is
         * deindexing production if the Host header ever arrives rewritten by a
         * proxy. This form's failure mode is a new environment being indexable
         * until someone adds it here — recoverable, where the other is not.
         *
         * Any new non-production hostname must be added to this list.
         */
        source: '/:path*',
        has: [{ type: 'host', value: 'stx.schoolcompare.co.uk' }],
        headers: [
          {
            key: 'X-Robots-Tag',
            value: 'noindex, nofollow',
          },
        ],
      },
      {
        source: '/:path*',
        headers: [
          {
            key: 'X-DNS-Prefetch-Control',
            value: 'on',
          },
          {
            // Allow the analytics subdomain (Umami heatmap/recorder) to embed
            // the site while blocking all other origins. frame-ancestors is the
            // modern replacement for X-Frame-Options, which cannot allow a
            // specific sibling subdomain (ALLOW-FROM is deprecated/ignored).
            key: 'Content-Security-Policy',
            value: "frame-ancestors 'self' https://analytics.schoolcompare.co.uk",
          },
          {
            key: 'X-Content-Type-Options',
            value: 'nosniff',
          },
          {
            key: 'Referrer-Policy',
            value: 'origin-when-cross-origin',
          },
        ],
      },
      {
        // The mark is now the supplied raster artwork, so the favicon is
        // app/icon.png rather than an SVG. Pointing this at the old path was
        // caching a 404.
        source: '/icon.png',
        headers: [
          {
            key: 'Cache-Control',
            value: 'public, max-age=31536000, immutable',
          },
        ],
      },
    ];
  },
};

export default nextConfig;