mysql - NodeJS 和 MySQL，处理行

Question

我是 NodeJS 初学者，目前正在使用 node、express 和 mysql 包。我正在尝试检查此人是否已经注册。

如果是这样，则应执行以下代码:

    req.session.user = user;
    req.flash('success_notification', 'You are logged in');
    console.log("creating session :" ,req.session.user);

但是，当我尝试检查它是否设置为 true 时，authenticated 始终保持“false”。

 if (authenticated === true)

有人知道我做错了什么吗？

这是我处理登录尝试的代码:

router.post('/login', function (req, res) {
    var user = req.body.username;
    var password = req.body.password;
    var authenticated = false;

    var query = "Select * from  user where username = \'" + user + "\'" + " AND pw = \'" + password  + "\'";

    connection.query(query, function (err,rows,fields) {
        if (err) console.log(err);
        else if (rows.length) {
            authenticated = true;
            console.log(authenticated);
        }
        else {
            console.log('False Password or Username');
        }
    });

    console.log(authenticated);
    if (authenticated === true) {
        req.session.user = user;
        req.flash('success_notification', 'You are logged in');
        console.log("creating session :" ,req.session.user);
    }

    res.redirect('/');    
});

Answer 1

这是一个回调问题。

我也遇到了同样的问题。

条件 if (authenticated === true) 在查询完成之前得到验证并返回，因此 authenticated 仅在查询完成后才变为 true它验证了自己。

让它适用于任何类型的 bool 查询返回的方法是将其包含在您的查询中以创建回调函数。

因此，如果您将条件封装在查询中，它应该可以正常工作。

router.post('/login', function (req, res) {
    var user = req.body.username;
    var password = req.body.password;
    //var authenticated = false;

    var query = "Select * from  user where username = \'" + user + "\'" + " AND pw = \'" + password  + "\'";

    connection.query(query, function (err,rows,fields) {

        var authenticated = false; //Encapsulate your authenticated variable since you won't need it outside this scope

        if (err) console.log(err);
        else if (rows.length) {
            authenticated = true;
            console.log(authenticated);
        }
        else {
            console.log('False Password or Username');
        }

        /** Moved here */
        console.log(authenticated);
        if (authenticated === true) {
            req.session.user = user;
            req.flash('success_notification', 'You are logged in');
            console.log("creating session :" ,req.session.user);
        }

        res.redirect('/');

    });

    // Moved wihin the your query
    /*
    console.log(authenticated);
    if (authenticated === true) {
        req.session.user = user;
        req.flash('success_notification', 'You are logged in');
        console.log("creating session :" ,req.session.user);
    }

    res.redirect('/');
    */

});