refactor: migrate to Tencent Cloud backend

server/src/lib/db.js

@@ -0,0 +1,48 @@
+const mysql = require('mysql2/promise')
+const config = require('../config')
+
+let pool
+
+function getPool() {
+  if (!pool) {
+    pool = mysql.createPool({
+      host: config.db.host,
+      port: config.db.port,
+      user: config.db.user,
+      password: config.db.password,
+      database: config.db.database,
+      waitForConnections: true,
+      connectionLimit: 5,
+      namedPlaceholders: true,
+      timezone: '+08:00'
+    })
+  }
+  return pool
+}
+
+async function query(sql, params) {
+  const [rows] = await getPool().execute(sql, params || {})
+  return rows
+}
+
+async function one(sql, params) {
+  const rows = await query(sql, params)
+  return rows[0] || null
+}
+
+async function transaction(work) {
+  const conn = await getPool().getConnection()
+  try {
+    await conn.beginTransaction()
+    const result = await work(conn)
+    await conn.commit()
+    return result
+  } catch (err) {
+    await conn.rollback()
+    throw err
+  } finally {
+    conn.release()
+  }
+}
+
+module.exports = { getPool, query, one, transaction }