@esmx/core/dist/utils/middleware.mjs

A high-performance microfrontend framework supporting Vue, React, Preact, Solid, and Svelte with SSR and Module Federation capabilities.

import send from "send";
const reFinal = /\.final\.[a-zA-Z0-9]+$/;
export function isImmutableFile(filename) {
  return reFinal.test(filename);
}
export function createMiddleware(esmx) {
  const middlewares = Object.values(esmx.moduleConfig.links).map(
    (item) => {
      const base = `/${item.name}/`;
      const baseUrl = new URL(`file:`);
      const root = item.client;
      return (req, res, next) => {
        const url = req.url ?? "/";
        const { pathname } = new URL(req.url ?? "/", baseUrl);
        if (!url.startsWith(base) || req.method !== "GET") {
          next();
          return;
        }
        send(req, pathname.substring(base.length - 1), {
          root
        }).on("headers", () => {
          if (isImmutableFile(pathname)) {
            res.setHeader(
              "cache-control",
              "public, max-age=31536000, immutable"
            );
          } else {
            res.setHeader("cache-control", "no-cache");
          }
        }).pipe(res);
      };
    }
  );
  return mergeMiddlewares(middlewares);
}
export function mergeMiddlewares(middlewares) {
  return (req, res, next) => {
    let index = 0;
    function dispatch() {
      if (index < middlewares.length) {
        middlewares[index](req, res, () => {
          index++;
          dispatch();
        });
        return;
      } else {
        next();
      }
    }
    dispatch();
  };
}