Question

我正在创建基于承诺的API。如果我一次发出一个请求，一切正常，但是，如果两个或更多请求在一秒钟内到达服务器，我会收到以下错误

node multiple_sends.js

奇怪的是，我得到了一个有效且正确的结果返回给API请求，但显然有些问题。

我在gitHub上创建了here。您可以查看它，我已经创建了一个包含2个用户的SQL播种器，因此您只需将查询粘贴到您的数据库中（播种机甚至可以创建一个新的数据库）

项目很小，只需将数据库凭据放在configs / mysql.js文件中，然后运行文件// models/user.js let mysql = require('mysql'); let configs = { host : '127.0.0.1', user : 'root', password : 'something', database : 'demo' } /** * This constructor function is responsible for running queries against * the mysql database */ function Users() { // These are PRIVATE variables, they can only be accessed within this class let mysql_connection = null; this.getUserByEmail = function(email) { let parent = this; mysql_connection = mysql.createConnection(configs); return this.mysqlConnect() .then((connectionId) => { console.log(`getUserByEmail: connection id: ${connectionId}`); let sql = 'SELECT user_id, first_name, last_name, upassword, email, ' + 'birthday, roles FROM users WHERE email = ?'; return parent.runQuery(sql, [email]); }) .then((results) => { if (results.resultSet.length === 0) { return null; } let resultSet = results.resultSet[0]; // return our result to the calling method. return (resultSet); }) .catch(error => { throw error; }) } /** * Run this method when trying to connect to the database * @param Object error * @return Promise */ this.mysqlConnect = function() { return new Promise(function(resolve, reject) { mysql_connection.connect(function(error) { if (error) { console.log('Error making connection', error); throw "Failed connection to database"; } // we don't have to return anything, this is just to show that Promises // can return resolve(mysql_connection.threadId); }); }); } /** * use this method for running selects * @param string query - well formed query * @return Promise */ this.runQuery = function(query, params) { return new Promise(function(resolve, reject) { mysql_connection.query(query, params, function(error, results, fields) { mysql_connection.end((err) => { if (err) { console.log('error terminating connection: ', mysql_connection.threadId); console.log('error ', err); } }); if (error) { reject(error); } resolve({resultSet: results, fieldSet: fields}); }); }); } } module.exports = Users;

您将看到返回正确答案，但节点出错。

我不认为错误发生在mysql模块中。原因是，如果我从模型中获取代码并创建CLI脚本，则不会返回任何错误，mysql不会发出任何警告

//main.js
let Users = require ('./models/user');

function getUser1Info()
{
  user1.getUserByEmail('original.logger@example.com')
    .then(userData1 => {
      let ctime = new Date();
      console.log(ctime.getTime(), 'user data: ', userData1.user_id)
    })
    .catch((error) => {
      console.log('error!', error);
    });
}


function getUser2Info()
{
  user2.getUserByEmail('billy.b.parker@example.com')
    .then(userData2 => {
      let ctime = new Date();
      console.log(ctime.getTime(), 'user data: ', userData2.user_id)
    })
    .catch((error) => {
      console.log('error!', error);
    });
}

let user1 = new Users();
let user2 = new Users();

setTimeout(() => {
  getUser1Info();
}, 1000);

setTimeout(() => {
  getUser2Info();
}, 999);

这是调用模型的脚本

String html = getUrl("https://en.wikipedia.org/"+url);

此代码未在我的API中的models / user.js中修改。这让我相信我在Express中创建模型的方式从根本上被打破了。

感谢任何帮助

Answer 1

如果您使用node-mysql模块，只需删除.connect和.end即可。刚刚解决了这个问题。显然，他们在最后一次迭代中推送了不必要的代码，这也是错误的。如果您已经运行了createConnection调用
，则无需连接

Cannot enqueue Handshake after invoking quit

我还会做什么：使用Knex而不是普通的mysql

节点MySQL错误 - 错误：调用退出后无法排队退出

1 个答案: