fix: complete TechLog migration evidence

scripts/lib/tech-log-production-server.ts

@@ -0,0 +1,133 @@
+// @ts-nocheck -- copied byte-for-byte into the self-contained Node deployment artifact.
+import { readFile, stat } from "node:fs/promises";
+import { createServer } from "node:http";
+import path from "node:path";
+import process from "node:process";
+import { fileURLToPath, pathToFileURL } from "node:url";
+
+const contentTypes = Object.freeze({
+  ".css": "text/css;charset=UTF-8",
+  ".html": "text/html;charset=UTF-8",
+  ".js": "text/javascript;charset=UTF-8",
+  ".json": "application/json",
+  ".png": "image/png",
+  ".svg": "image/svg+xml",
+  ".woff": "font/woff",
+  ".woff2": "font/woff2",
+});
+
+function isStudioPath(pathname, prefix) {
+  return pathname === prefix || pathname.startsWith(`${prefix}/`);
+}
+
+async function sendFile(
+  file,
+  method,
+  response,
+  status = 200,
+) {
+  const body = await readFile(file);
+  response.writeHead(status, {
+    "Cache-Control": "no-cache",
+    "Content-Length": body.byteLength,
+    "Content-Type": contentTypes[path.extname(file)] ?? "application/octet-stream",
+    Vary: "Origin",
+  });
+  if (method === "HEAD") {
+    response.end();
+    return;
+  }
+  response.end(body);
+}
+
+export function createTechLogProductionServer({
+  root,
+  contract,
+}) {
+  const absoluteRoot = path.resolve(root);
+  const publicSpaPaths = new Set(contract.publicSpaPaths);
+  const studioSpaPathPatterns = contract.studioSpaPathPatterns.map(
+    (pattern) => new RegExp(pattern),
+  );
+  const server = createServer(async (request, response) => {
+    if (request.method !== "GET" && request.method !== "HEAD") {
+      response.writeHead(405, { Allow: "GET, HEAD" }).end();
+      return;
+    }
+    try {
+      const url = new URL(request.url ?? "/", "http://127.0.0.1");
+      const pathname = decodeURIComponent(url.pathname);
+      const requested = path.resolve(absoluteRoot, `.${pathname}`);
+      if (
+        requested !== absoluteRoot &&
+        requested.startsWith(`${absoluteRoot}${path.sep}`)
+      ) {
+        const details = await stat(requested).catch(() => null);
+        if (details?.isFile()) {
+          await sendFile(requested, request.method, response);
+          return;
+        }
+      }
+      if (
+        publicSpaPaths.has(pathname) ||
+        studioSpaPathPatterns.some((pattern) => pattern.test(pathname))
+      ) {
+        await sendFile(path.join(absoluteRoot, "index.html"), request.method, response);
+        return;
+      }
+      if (isStudioPath(pathname, contract.studioPathPrefix)) {
+        await sendFile(
+          path.join(absoluteRoot, "index.html"),
+          request.method,
+          response,
+          contract.notFound.status,
+        );
+        return;
+      }
+      response.writeHead(contract.notFound.status, {
+        "Content-Type": contract.notFound.contentType,
+      });
+      response.end(request.method === "HEAD" ? undefined : contract.notFound.body);
+    } catch {
+      response.writeHead(contract.notFound.status, {
+        "Content-Type": contract.notFound.contentType,
+      });
+      response.end(request.method === "HEAD" ? undefined : contract.notFound.body);
+    }
+  });
+  return server;
+}
+
+function optionValue(name) {
+  const index = process.argv.indexOf(name);
+  return index >= 0 ? process.argv[index + 1] : undefined;
+}
+
+async function startFromCommandLine() {
+  const root = path.resolve(
+    optionValue("--root") ?? path.dirname(fileURLToPath(import.meta.url)),
+  );
+  const host = optionValue("--host") ?? "127.0.0.1";
+  const port = Number(optionValue("--port") ?? 4173);
+  if (!Number.isInteger(port) || port < 1 || port > 65_535) {
+    throw new TypeError("--port must be an integer from 1 through 65535");
+  }
+  const contract = JSON.parse(
+    await readFile(path.join(root, "tech-log-serving-contract.json"), "utf8"),
+  );
+  const server = createTechLogProductionServer({ root, contract });
+  server.listen(port, host, () => {
+    process.stdout.write(`TechLog production server: ${root} on http://${host}:${port}\n`);
+  });
+  for (const signal of ["SIGINT", "SIGTERM"]) {
+    process.on(signal, () => server.close(() => process.exit(0)));
+  }
+}
+
+const commandPath = process.argv[1];
+if (
+  commandPath &&
+  import.meta.url === pathToFileURL(path.resolve(commandPath)).href
+) {
+  await startFromCommandLine();
+}