refactor: migrate to nextjs serverless handler for vercel

package.json

@@ -4,8 +4,9 @@
   "description": "",
   "main": "index.js",
   "scripts": {
-    "test": "echo \"Error: no test specified\" && exit 1",
-    "start": "node index.js"    
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start"
   },
   "keywords": [],
   "author": "",
@@ -13,9 +14,13 @@
   "type": "commonjs",
   "dependencies": {
     "@apollo/server": "^5.5.1",
+    "@as-integrations/next": "^4.1.0",
     "cors": "^2.8.6",
     "dotenv": "^17.4.2",
     "graphql": "^16.14.2",
-    "pg": "^8.23.0"
+    "next": "^16.3.4",
+    "pg": "^8.23.0",
+    "react": "^19.2.8",
+    "react-dom": "^19.2.8"
   }
 }

pages/api/graphql.js

@@ -0,0 +1,96 @@
+const { ApolloServer } = require('@apollo/server');
+const { startServerAndCreateNextHandler } = require('@as-integrations/next');
+const { Pool } = require('pg');
+
+const pool = new Pool({
+  connectionString: process.env.DATABASE_URL,
+  ssl: {
+    rejectUnauthorized: false,
+  },
+  max: 1, // Menjaga batas koneksi pada lingkungan serverless
+});
+
+const typeDefs = `#graphql
+  type Category {
+    id: ID!
+    name: String!
+    description: String
+    products: [Product!]!
+  }
+
+  type Product {
+    id: ID!
+    title: String!
+    price: Float!
+    category_id: Int
+    created_by: ID
+    category: Category
+  }
+
+  type Query {
+    categories: [Category!]!
+    category(id: ID!): Category
+    products: [Product!]!
+    product(id: ID!): Product
+  }
+`;
+
+const resolvers = {
+  Query: {
+    categories: async () => {
+      const result = await pool.query('SELECT * FROM categories ORDER BY id ASC');
+      return result.rows;
+    },
+    category: async (_, { id }) => {
+      const result = await pool.query('SELECT * FROM categories WHERE id = $1', [id]);
+      return result.rows[0] || null;
+    },
+    products: async () => {
+      const result = await pool.query('SELECT id, title, price::float, category_id, created_by FROM products ORDER BY id ASC');
+      return result.rows;
+    },
+    product: async (_, { id }) => {
+      const result = await pool.query('SELECT id, title, price::float, category_id, created_by FROM products WHERE id = $1', [id]);
+      return result.rows[0] || null;
+    },
+  },
+  Category: {
+    products: async (parent) => {
+      const result = await pool.query(
+        'SELECT id, title, price::float, category_id, created_by FROM products WHERE category_id = $1 ORDER BY id ASC',
+        [parent.id]
+      );
+      return result.rows;
+    },
+  },
+  Product: {
+    category: async (parent) => {
+      if (!parent.category_id) return null;
+      const result = await pool.query('SELECT * FROM categories WHERE id = $1', [parent.category_id]);
+      return result.rows[0] || null;
+    },
+  },
+};
+
+const server = new ApolloServer({
+  typeDefs,
+  resolvers,
+  introspection: true,
+});
+
+const apolloHandler = startServerAndCreateNextHandler(server);
+
+// Wrapper untuk menangani CORS Apollo Studio Sandbox
+module.exports = async function handler(req, res) {
+  res.setHeader('Access-Control-Allow-Credentials', 'true');
+  res.setHeader('Access-Control-Allow-Origin', 'https://studio.apollographql.com');
+  res.setHeader('Access-Control-Allow-Methods', 'GET,OPTIONS,POST');
+  res.setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization');
+
+  if (req.method === 'OPTIONS') {
+    res.status(200).end();
+    return;
+  }
+
+  return apolloHandler(req, res);
+};