mysql - Node.js 在 MySQL 查询上崩溃

Question

我需要帮助解决我遇到的这个问题。如果用户名或密码不在数据库中，我的登录脚本会导致 Node 崩溃，代码如下:

/* Login */
exports.login = function(req, res){
    var post = req.body;
    var mysql = require('mysql');
    var db = mysql.createConnection({
      host      : 'localhost',
      user      : 'root',
      password  : 'root',
      database  : 'node01',
    });
    var selectStmt = 'SELECT * FROM users WHERE name = "' + post.user +'"';
    db.connect();

    db.query(selectStmt, function(err, rows, fields) {
      if(err) throw err;
      else if(rows[0].name == post.user && rows[0].password == post.password){
        req.session.auth_id = rows[0].id;
        req.session.user = rows[0].name;
        res.redirect('/adminindex');
      }
      else res.redirect('/admin');
    });

    db.end();
};

以及我得到的错误

TypeError: Cannot read property 'name' of undefined
at Query.exports.login [as _callback] (../node-project01/routes/login.js:18:19)
at Query.Sequence.end (../node-project01/node_modules/mysql/lib/protocol/sequences/Sequence.js:66:24)
at Query._handleFinalResultPacket (../node-project01/node_modules/mysql/lib/protocol/sequences/Query.js:138:8)
at Query.EofPacket (../node-project01/node_modules/mysql/lib/protocol/sequences/Query.js:122:8)
at Protocol._parsePacket (../node-project01/node_modules/mysql/lib/protocol/Protocol.js:165:24)
at Parser.write (../node-project01/node_modules/mysql/lib/protocol/Parser.js:60:12)
at Protocol.write (../node-project01/node_modules/mysql/lib/protocol/Protocol.js:32:16)
at Socket.ondata (stream.js:38:26)
at Socket.EventEmitter.emit (events.js:96:17)
at TCP.onread (net.js:396:14)

关于如何解决这个问题有什么想法吗？

Answer 1

嗯，考虑到你的问题是从12月开始的，我想你已经解决了这个问题。但是，您的问题可能是因为您的查询没有结果，然后“rows[0]”未定义。在使用“行”变量之前，您始终应该测试是否有任何结果，例如:

if (rows.length > 0) {
  // your code here
}

问候，