如何在flask中使用ajax从sql中调用用户名？

from flask import Flask, request, jsonify
import pymysql

conn = pymysql.connect(host='数据库主机地址', user='用户名', password='密码', db='数据库名', charset='utf8mb4')
cursor = conn.cursor()

app = Flask(__name__)

@app.route('/get_username', methods=['POST'])
def get_username():
    user_id = request.form['user_id']
    cursor.execute("SELECT username FROM users WHERE id = %s", (user_id,))
    result = cursor.fetchone()
    if result:
        username = result[0]
        return jsonify({'username': username})
    else:
        return jsonify({'error': 'User not found'})

if __name__ == '__main__':
    app.run()

$.ajax({
    url: '/get_username',
    type: 'POST',
    data: {user_id: 1},
    success: function(response) {
        if ('username' in response) {
            var username = response.username;
            // 处理用户名
        } else {
            var error = response.error;
            // 处理错误信息
        }
    },
    error: function(xhr, status, error) {
        // 处理错误
    }
});