Function staticFiles

packages/fresh/src/middlewares/static_files.ts:22–133

()

 * ```
 */
export function staticFiles<T>(): Middleware<T> {
  return async function freshServeStaticFiles(ctx) {
    const { req, url, config } = ctx;

    const buildCache = getBuildCache(ctx);
    if (buildCache === null) return await ctx.next();

    let pathname = url.pathname;
    if (config.basePath) {
      pathname = pathname !== config.basePath
        ? pathname.slice(config.basePath.length)
        : "/";
    }

    try {
      pathname = normalizePathname(decodeURIComponent(pathname));
    } catch (_e: unknown) {
      if (!(_e instanceof URIError)) throw _e;
      return await ctx.next();
    }

    // Fast path bail out
    const startTime = performance.now() + performance.timeOrigin;
    const file = await buildCache.readFile(pathname);
    if (pathname === "/" || file === null) {
      // Optimization: Prevent long responses for favicon.ico requests
      if (pathname === "/favicon.ico") {
        return new Response(null, { status: 404 });
      }
      return await ctx.next();
    }

    if (req.method !== "GET" && req.method !== "HEAD") {
      file.close();
      return new Response("Method Not Allowed", { status: 405 });
    }

    const span = tracer.startSpan("static file", {
      attributes: { "fresh.span_type": "static_file" },
      startTime,
    });

    try {
      const cacheKey = url.searchParams.get(ASSET_CACHE_BUST_KEY);
      if (cacheKey !== null && BUILD_ID !== cacheKey) {
        url.searchParams.delete(ASSET_CACHE_BUST_KEY);
        const location = url.pathname + url.search;
        file.close();
        span.setAttribute("fresh.cache", "invalid_bust_key");
        span.setAttribute("fresh.cache_key", cacheKey);
        return new Response(null, {
          status: 307,
          headers: {
            location,
          },
        });
      }