INIT

server/proxy.mjs

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+// Optional reverse proxy + static host for the built PWA.
+//
+//   HERMES_TARGET=https://hermes.example.com PORT=8787 node server/proxy.mjs
+//
+// Why use it? A browser PWA served from a different origin than Hermes needs
+// the Hermes server to send CORS headers *and* allow credentialed cookies.
+// Serving the app from this proxy puts the app and the API on the same origin,
+// so the `hermes_session` cookie just works — and SSE streams pass through
+// unbuffered. It uses only Node built-ins (no dependencies).
+//
+import { createServer } from "node:http";
+import { request as httpsRequest } from "node:https";
+import { request as httpRequest } from "node:http";
+import { readFile, stat } from "node:fs/promises";
+import { extname, join, normalize, resolve } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const __dirname = resolve(fileURLToPath(import.meta.url), "..");
+const DIST = resolve(__dirname, "../dist");
+const PORT = Number(process.env.PORT || 8787);
+const TARGET = process.env.HERMES_TARGET;
+// Optional: inject the API key server-side so it never reaches the browser.
+const API_KEY = process.env.HERMES_API_KEY;
+
+if (!TARGET) {
+  console.error("Set HERMES_TARGET to your Hermes base URL, e.g.");
+  console.error("  HERMES_TARGET=https://hermes.example.com node server/proxy.mjs");
+  process.exit(1);
+}
+
+const target = new URL(TARGET);
+const isHttps = target.protocol === "https:";
+const doRequest = isHttps ? httpsRequest : httpRequest;
+
+const MIME = {
+  ".html": "text/html; charset=utf-8",
+  ".js": "text/javascript; charset=utf-8",
+  ".css": "text/css; charset=utf-8",
+  ".json": "application/json; charset=utf-8",
+  ".svg": "image/svg+xml",
+  ".png": "image/png",
+  ".jpg": "image/jpeg",
+  ".jpeg": "image/jpeg",
+  ".webp": "image/webp",
+  ".ico": "image/x-icon",
+  ".webmanifest": "application/manifest+json",
+  ".woff2": "font/woff2",
+  ".map": "application/json",
+};
+
+function proxy(req, res) {
+  const headers = { ...req.headers };
+  headers.host = target.host;
+  if (API_KEY && !headers.authorization) {
+    headers.authorization = `Bearer ${API_KEY}`;
+  }
+  // Let the upstream decide; we forward the original origin for CSRF checks.
+  const options = {
+    protocol: target.protocol,
+    hostname: target.hostname,
+    port: target.port || (isHttps ? 443 : 80),
+    method: req.method,
+    path: req.url,
+    headers,
+  };
+
+  const upstream = doRequest(options, (upRes) => {
+    // Strip hop-by-hop headers.
+    const outHeaders = { ...upRes.headers };
+    delete outHeaders["transfer-encoding"];
+    delete outHeaders["connection"];
+    // Ensure SSE is not buffered by any intermediary.
+    if (String(outHeaders["content-type"] || "").includes("text/event-stream")) {
+      outHeaders["x-accel-buffering"] = "no";
+      outHeaders["cache-control"] = "no-cache";
+    }
+    res.writeHead(upRes.statusCode || 502, outHeaders);
+    upRes.pipe(res);
+  });
+
+  upstream.on("error", (err) => {
+    res.writeHead(502, { "content-type": "application/json" });
+    res.end(JSON.stringify({ error: `Upstream error: ${err.message}` }));
+  });
+
+  req.pipe(upstream);
+}
+
+async function serveStatic(req, res) {
+  let pathname = decodeURIComponent((req.url || "/").split("?")[0]);
+  if (pathname === "/") pathname = "/index.html";
+  const filePath = normalize(join(DIST, pathname));
+
+  if (!filePath.startsWith(DIST)) {
+    res.writeHead(403);
+    res.end("Forbidden");
+    return;
+  }
+
+  try {
+    const info = await stat(filePath);
+    if (info.isDirectory()) throw new Error("dir");
+    const data = await readFile(filePath);
+    const type = MIME[extname(filePath)] || "application/octet-stream";
+    const immutable = pathname.startsWith("/assets/");
+    res.writeHead(200, {
+      "content-type": type,
+      "cache-control": immutable ? "public, max-age=31536000, immutable" : "no-cache",
+    });
+    res.end(data);
+  } catch {
+    // SPA fallback.
+    try {
+      const html = await readFile(join(DIST, "index.html"));
+      res.writeHead(200, { "content-type": MIME[".html"], "cache-control": "no-cache" });
+      res.end(html);
+    } catch {
+      res.writeHead(404, { "content-type": "text/plain" });
+      res.end("Not found. Did you run `npm run build` first?");
+    }
+  }
+}
+
+const server = createServer((req, res) => {
+  const path = req.url || "";
+  if (path.startsWith("/api/") || path.startsWith("/v1/") || path.startsWith("/health")) {
+    proxy(req, res);
+  } else {
+    void serveStatic(req, res);
+  }
+});
+
+server.listen(PORT, () => {
+  console.log(`Hermes PWA proxy listening on http://localhost:${PORT}`);
+  console.log(`  serving:  ${DIST}`);
+  console.log(`  proxying: /api/*, /v1/* -> ${target.origin}`);
+  if (API_KEY) console.log("  injecting: Authorization: Bearer <HERMES_API_KEY>");
+});