fix db initialization to make the server run

Author: rinaldo stevenazzi

.next/trace

@@ -0,0 +1,2 @@
+[{"name":"next-dev","duration":375778,"timestamp":48743038978,"id":1,"tags":{},"startTime":1755273250317,"traceId":"67ad9cb661b8ac33"}]
+[{"name":"generate-buildid","duration":97,"timestamp":48766044509,"id":4,"parentId":1,"tags":{},"startTime":1755273273323,"traceId":"6b2fe1b57754ff3a"},{"name":"load-custom-routes","duration":160,"timestamp":48766044646,"id":5,"parentId":1,"tags":{},"startTime":1755273273323,"traceId":"6b2fe1b57754ff3a"},{"name":"next-build","duration":47457,"timestamp":48765998214,"id":1,"tags":{"buildMode":"default","isTurboBuild":"false","version":"15.4.6"},"startTime":1755273273276,"traceId":"6b2fe1b57754ff3a"}]

api/index.ts

@@ -0,0 +1,149 @@
+// api/index.ts
+import express from "express";
+import "dotenv/config";
+import Global from "../src/controllers/Global.ts";
+import EVENTS from "../src/constants/events.ts";
+
+const app = express();
+app.use(express.json());
+
+// --- Initialize DB on cold start and await before handling requests ---
+const globalController = new Global();
+const ready = (async () => {
+  try {
+    await globalController.initDB();
+    console.log("SERVER - initDB - DONE");
+  } catch (e) {
+    console.error("SERVER - initDB - ERROR", e);
+    throw e;
+  }
+})();
+
+app.use(async (_req, _res, next) => {
+  try {
+    await ready; // wait for cold-start DB init once
+    next();
+  } catch (e) {
+    next(e);
+  }
+});
+
+// --- Debug route (remove once stable) ---
+app.get("/__debug", async (_req, res) => {
+  res.json({
+    hasMongoURI: Boolean(process.env.MONGODB_URI),
+    vercelEnv: process.env.VERCEL_ENV || null,
+    nodeVersion: process.version,
+  });
+});
+
+// --- Health/base route ---
+app.get("/", async (_req, res) => {
+  console.log("GET /");
+  res.send("<h1>Hello world</h1>");
+});
+
+// --- Routes ---
+app.post(
+  "/score",
+  async (
+    req: express.Request<{}, {}, { score: number }>,
+    res: express.Response
+  ) => {
+    try {
+      const { score } = req.body;
+      const result = await globalController.checkScore(score);
+      return result.message === EVENTS.SCORED
+        ? res.status(200).send()
+        : res.status(409).send();
+    } catch (e) {
+      console.error("POST /score error:", e);
+      return res.status(500).json({ error: "Internal error" });
+    }
+  }
+);
+
+app.post(
+  "/adduser",
+  async (
+    req: express.Request<
+      {},
+      {},
+      { userName: string; password: string; score?: number }
+    >,
+    res: express.Response
+  ) => {
+    try {
+      const { userName, password, score } = req.body;
+      const result = await globalController.addUser({
+        userName,
+        password,
+        score,
+      });
+      if (result.message === EVENTS.USER_ALREADY_EXIST)
+        return res.status(409).send("User Already Exist.");
+      if (result.message === EVENTS.USER_CREATED)
+        return res.status(200).json(result.list);
+      return res.send();
+    } catch (e) {
+      console.error("POST /adduser error:", e);
+      return res.status(500).json({ error: "Internal error" });
+    }
+  }
+);
+
+app.post(
+  "/users/:userName/scores",
+  async (
+    req: express.Request<{ userName: string }, {}, { value: number }>,
+    res: express.Response
+  ) => {
+    try {
+      const { userName } = req.params;
+      const { value } = req.body;
+      if (typeof value !== "number")
+        return res.status(400).send("value must be a number");
+      const result = await globalController.addScoreForUser(userName, value);
+      return result.message === EVENTS.SCORED && result.created
+        ? res.status(201).json({ userId: result.userId, value })
+        : res.status(409).send();
+    } catch (e) {
+      console.error("POST /users/:userName/scores error:", e);
+      return res.status(500).json({ error: "Internal error" });
+    }
+  }
+);
+
+app.get("/users", async (_req, res) => {
+  try {
+    const list = await globalController.listUsersPublic();
+    return res.status(200).json(list);
+  } catch (e) {
+    console.error("GET /users error:", e);
+    return res.status(500).json({ error: "Internal error" });
+  }
+});
+
+app.get(
+  "/scores/top",
+  async (
+    req: express.Request<{}, {}, {}, { limit?: string }>,
+    res: express.Response
+  ) => {
+    try {
+      const raw = req.query.limit;
+      const parsed = raw ? parseInt(String(raw), 10) : 10;
+      const limit = Number.isFinite(parsed)
+        ? Math.min(Math.max(parsed, 1), 50)
+        : 10;
+      const rows = await globalController.getTopScores(limit);
+      return res.status(200).json(rows);
+    } catch (e) {
+      console.error("GET /scores/top error:", e);
+      return res.status(500).json({ error: "Internal error" });
+    }
+  }
+);
+
+// Do NOT call app.listen() on Vercel. Export the app for the Serverless Function.
+export default app;

package.json

@@ -5,9 +5,9 @@
   "main": "src/api/index.ts",
   "type": "module",
   "scripts": {
-    "dev": "node src/api/index.ts",
-    "build": "node -p tsconfig.json",
-    "start": "node src/api/index.ts",
+    "dev": "node api/index.ts",
+    "build": "echo \"No build step for Vercel Functions\"",
+    "start": "node api/index.ts",
     "typecheck": "tsc -p tsconfig.json --noEmit",
     "test": "echo \"Error: no test specified\" && exit 1",
     "seed": "node src/scripts/seeder.ts"

src/api/index.ts

@@ -29,9 +29,12 @@ export default class Global {
   async initDB(): Promise<void> {
     try {
       const db = await this.mongoDB.connect();
+      console.log("Global Controller - initDB initialisation successful");
       this.db = db;
       this.users.init(db);
+      console.log("Global Controller - initDB users initialised");
       this.scores.init(db);
+      console.log("Global Controller - initDB scores initialised");
     } catch (e) {
       // eslint-disable-next-line no-console
       console.log("Global Controller - initDB initialisation failed !!!");

src/controllers/Global.ts

@@ -120,7 +120,8 @@ app.get(
 
 // ❗ run the HTTP listener only when NOT on Vercel
 // if (!process.env.VERCEL_ENV) {
-//   console.log(`Listening on port ${PORT}`);
+console.log(`VERCEL_ENV : ${process.env.VERCEL_ENV}`);
+console.log(`Listening on port ${PORT}`);
 server.listen(PORT, () => console.log(`Listening on ${PORT}`));
 // }
 

src/index.ts

@@ -11,7 +11,13 @@ export default class MongoDB {
   constructor() {
     // eslint-disable-next-line no-console
     console.log("MongoDB Class - Constructor");
-    this.client = new MongoClient(uri);
+    this.client = new MongoClient(uri, {
+      serverSelectionTimeoutMS: 10000, // fail fast if unreachable
+      connectTimeoutMS: 10000,
+      maxPoolSize: 5,
+      retryWrites: true,
+    });
+    console.log("MongoDB Class - client initialized", this.client);
   }
 
   async connect(): Promise<Db> {

src/services/MongoDB.ts

@@ -5,6 +5,5 @@
     "module": "nodenext",
     "rewriteRelativeImportExtensions": true,
     "erasableSyntaxOnly": true
-    // "verbatimModuleSyntax": true
   }
 }

tsconfig.json

@@ -1,3 +1,7 @@
 {
+  "$schema": "https://openapi.vercel.sh/vercel.json",
+  "framework": null,
+  "buildCommand": "",
+  "outputDirectory": null,
   "rewrites": [{ "source": "/(.*)", "destination": "/api" }]
 }