feat(ui): add operator UI server, stores, and insights

src/ui/http-utils.ts

@@ -0,0 +1,90 @@
+import { createReadStream } from "node:fs";
+import { stat } from "node:fs/promises";
+import { extname, resolve } from "node:path";
+import type { IncomingMessage, ServerResponse } from "node:http";
+
+const CONTENT_TYPES: Record<string, string> = {
+  ".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",
+};
+
+export function sendJson(response: ServerResponse, statusCode: number, body: unknown): void {
+  const payload = JSON.stringify(body);
+  response.statusCode = statusCode;
+  response.setHeader("Content-Type", "application/json; charset=utf-8");
+  response.end(payload);
+}
+
+export function sendText(response: ServerResponse, statusCode: number, body: string): void {
+  response.statusCode = statusCode;
+  response.setHeader("Content-Type", "text/plain; charset=utf-8");
+  response.end(body);
+}
+
+export async function parseJsonBody<T>(request: IncomingMessage): Promise<T> {
+  const chunks: Buffer[] = [];
+
+  await new Promise<void>((resolveBody, rejectBody) => {
+    request.on("data", (chunk: Buffer) => {
+      chunks.push(chunk);
+    });
+    request.on("end", () => resolveBody());
+    request.on("error", rejectBody);
+  });
+
+  const body = Buffer.concat(chunks).toString("utf8").trim();
+  if (!body) {
+    throw new Error("Request body is required.");
+  }
+
+  return JSON.parse(body) as T;
+}
+
+export function methodNotAllowed(response: ServerResponse): void {
+  sendJson(response, 405, {
+    ok: false,
+    error: "Method not allowed.",
+  });
+}
+
+export function notFound(response: ServerResponse): void {
+  sendJson(response, 404, {
+    ok: false,
+    error: "Not found.",
+  });
+}
+
+export async function serveStaticFile(input: {
+  response: ServerResponse;
+  filePath: string;
+}): Promise<boolean> {
+  try {
+    const absolutePath = resolve(input.filePath);
+    const fileStats = await stat(absolutePath);
+    if (!fileStats.isFile()) {
+      return false;
+    }
+
+    const extension = extname(absolutePath).toLowerCase();
+    const contentType = CONTENT_TYPES[extension] ?? "application/octet-stream";
+    input.response.statusCode = 200;
+    input.response.setHeader("Content-Type", contentType);
+
+    await new Promise<void>((resolveStream, rejectStream) => {
+      const stream = createReadStream(absolutePath);
+      stream.on("error", rejectStream);
+      stream.on("end", () => resolveStream());
+      stream.pipe(input.response);
+    });
+
+    return true;
+  } catch (error) {
+    if ((error as NodeJS.ErrnoException).code === "ENOENT") {
+      return false;
+    }
+    throw error;
+  }
+}