Fully customizable bun server for Astro

import type { AstroAdapter, AstroIntegration } from "astro";
import path from "path";

export function getAdapter(...args: unknown[]): AstroAdapter {
  return {
    args,
    // from Astro we only need manifest file and that's it.
    exports: ["manifest"],
    // Custom name for our adapter
    name: "bun-custom-adapter",
    // Here's the name of the file with server entrypoint
    // See the details below
    serverEntrypoint: path.join(import.meta.dirname, "bun-adapter.js"),
    // Here you can set supported astro features
    supportedAstroFeatures: {
      envGetSecret: "unsupported",
      hybridOutput: "unsupported",
      i18nDomains: "unsupported",
      serverOutput: "stable",
      sharpImageService: "stable",
      staticOutput: "stable",
    },
  };
}

export function astroBunAdapter(): AstroIntegration {
  return {
    name: "bun-custom-adapter",
    hooks: {
      "astro:config:done": (params) => {
        params.setAdapter(
          getAdapter({
            assets: params.config.build.assets,
            client: params.config.build.client?.toString(),
            host: params.config.server.host,
            port: params.config.server.port,
            server: params.config.build.server?.toString(),
          }),
        );
      },
    },
  };
}

import type { SSRManifest } from "astro";

// All we need from astro-adapter is ssr manifest
// Adapter is ready!
export function createExports(manifest: SSRManifest): {
  manifest: SSRManifest;
} {
  return { manifest };
}

import { App } from "astro/app";
import Bun from "bun";
import { Hono } from "hono";
import { serveStatic } from "hono/bun";

// Import our built manifest
import { manifest } from "./dist/server/entry.mjs";

// create apps
const app = new Hono();
const astroApp = new App(manifest);

// Serve static files from _astro folder
app.get(
  "/_astro/*",
  serveStatic({
    precompressed: true,
    root: "./dist/client",
    onFound(_, context) {
      // Here you can customize headers and do whatever you want
      // I just added caching headers for static files
      context.res.headers.set("Cache-Control", "public, max-age=31536000, immutable");
    },
  }),
);

// Here we serve files from /public folder (they're just copied)
app.get("/:filename{.+\\.(png|ico|txt)}", serveStatic({ root: "./dist/client" }));

// Here we render astro app
// If you use API routes, you may also want to allow other methods
app.on(["GET"], "*", (context) => {
  const routeData = astroApp.match(context.req.raw);

  if (!routeData) return new Response("Not Found", { status: 404 });

  return astroApp.render(context.request.raw, {
    addCookieHeader: true,
    routeData,
    // you can also pass client address here from
    // request headers if you need it
  });
});

// run our server
const server = Bun.serve({
  hostname: YOUR_HOST,
  port: YOUR_PORT,
  fetch: app.fetch,
});

const exit = () => server.stop();

process.once("SIGINT", exit);
process.once("SIGTERM", exit);
process.once("exit", exit);