import type {IncomingMessage, ServerResponse} from "node:http";
import {NodeRequest, sendNodeResponse} from "srvx/node";
import {staticMiddleware} from "srvx/static";
export type StaticFileServer = (request: IncomingMessage, response: ServerResponse) => void;
const escapeHtml = (value: string): string => value.replace(/[&<>"']/g, (char) => `&#${char.charCodeAt(0)};`);
/** Terminal `404` handler for requests no file matched, mirroring the response `finalhandler` used to produce. */
export function sendNotFound(request: IncomingMessage, response: ServerResponse): void {
const method = request.method /* v8 ignore next */ ?? "GET";
const url = request.url /* v8 ignore next */ ?? "/";
const message = escapeHtml(`Cannot ${method} ${encodeURI(url)}`);
const body = `\n\n\n\nError\n\n\n${message}\n\n\n`;
response.setHeader("Content-Security-Policy", "default-src 'none'");
response.setHeader("X-Content-Type-Options", "nosniff");
response.setHeader("Content-Type", "text/html; charset=utf-8");
response.setHeader("Content-Length", Buffer.byteLength(body));
response.writeHead(404);
response.end(body);
}
/**
* Serves `dir` on top of a plain `node:http` server, preferring the precompressed `.br`/`.gz` variant of a file when the client accepts it.
*
* Requests that match no file are answered by {@link sendNotFound}.
*/
export function createStaticFileServer(dir: string, logError: (message: string) => void): StaticFileServer {
// `compress: false` restricts serving to the precompressed variants shipped on disk, never compressing on the fly
const serveDir = staticMiddleware({dir, encodings: true, compress: false});
const handle = async (request: IncomingMessage, response: ServerResponse): Promise => {
let matched = true;
const staticResponse = await serveDir(new NodeRequest({req: request, res: response}), () => {
matched = false;
return new Response(null, {status: 404});
});
if (!matched) {
sendNotFound(request, response);
return;
}
// the HTML entry document must never be cached, so a newly installed frontend version is picked up right away
if (staticResponse.headers.get("Content-Type")?.startsWith("text/html")) {
staticResponse.headers.set("Cache-Control", "no-store");
}
await sendNodeResponse(response, staticResponse);
};
return (request, response) => {
handle(request, response).catch((error) => {
logError(`Failed to serve '${request.url}': ${(error as Error).message}`);
if (!response.headersSent) {
response.writeHead(500);
}
response.end();
});
};
}