server.ts

import { createRequestHandler } from "@remix-run/express";
import compression from "compression";
import express from "express";
import morgan from "morgan";

const viteDevServer =
  process.env.NODE_ENV === "production"
    ? undefined
    : await import("vite").then((vite) =>
        vite.createServer({
          server: { middlewareMode: true },
        }),
      );

const app = express();

app.use((req, res, next) => {
  // helpful headers:
  res.set("x-fly-region", process.env.FLY_REGION ?? "unknown");
  res.set("Strict-Transport-Security", `max-age=${60 * 60 * 24 * 365 * 100}`);

  // /clean-urls/ -> /clean-urls
  if (req.path.endsWith("/") && req.path.length > 1) {
    const query = req.url.slice(req.path.length);
    const safepath = req.path.slice(0, -1).replace(/\/+/g, "/");
    res.redirect(301, safepath + query);
    return;
  }
  next();
});

// if we're not in the primary region, then we need to make sure all
// non-GET/HEAD/OPTIONS requests hit the primary region rather than read-only
// Postgres DBs.
// learn more: https://fly.io/docs/getting-started/multi-region-databases/#replay-the-request
app.all("*", function getReplayResponse(req, res, next) {
  const { method, path: pathname } = req;
  const { PRIMARY_REGION, FLY_REGION } = process.env;

  const isMethodReplayable = !["GET", "OPTIONS", "HEAD"].includes(method);
  const isReadOnlyRegion =
    FLY_REGION && PRIMARY_REGION && FLY_REGION !== PRIMARY_REGION;

  const shouldReplay = isMethodReplayable && isReadOnlyRegion;

  if (!shouldReplay) return next();

  const logInfo = {
    pathname,
    method,
    PRIMARY_REGION,
    FLY_REGION,
  };
  console.info(`Replaying:`, logInfo);
  res.set("fly-replay", `region=${PRIMARY_REGION}`);
  return res.sendStatus(409);
});

app.use(compression());

// http://expressjs.com/en/advanced/best-practice-security.html#at-a-minimum-disable-x-powered-by-header
app.disable("x-powered-by");

if (viteDevServer) {
  app.use(viteDevServer.middlewares);
} else {
  app.use(
    "/assets",
    express.static("build/client/assets", {
      immutable: true,
      maxAge: "1y",
    }),
  );
}
app.use(express.static("build/client", { maxAge: "1h" }));

app.use(morgan("tiny"));

app.all(
  "*",
  createRequestHandler({
    // @ts-ignore
    build: viteDevServer
      ? () => viteDevServer.ssrLoadModule("virtual:remix/server-build")
      : // @ts-ignore
        await import("./build/server/index.js"),
  }),
);

const port = process.env.PORT || 3000;

app.listen(port, () => {
  console.log(`✅ app ready: http://localhost:${port}`);
});