CODEWITHSUNDEEP
mysqlnode.jsexpress
ZMath_lin
ZMath_lin

Reputation: 553

nodejs connect mysql error

I use mysql and express to write a easy login system.

database.js:

var mysql = require('mysql');
var config = require('../config/config');

var pool = mysql.createPool(config.mysql_dev);

var query=function(sql,callback){  
    pool.getConnection(function(err,conn){  
        if(err) console.log("POOL ==> " + err);
        else{  
            conn.query(sql,function(qerr,vals,fields){  
                //release connection  
                conn.release();
                callback(qerr,vals,fields);  

            });  
        }  
    });  
};  

module.exports=query;

index.js:

router.post('/login',function(req,res){ 
    var query = require('../modules/database');
    query("select * from managers where ManagerID =10001",function(err,vals,fields){  
        var temp=JSON.stringify(vals);

        var manager = JSON.parse(temp)[0];

        if(req.body.password===manager.password){
           req.session.manager = manager;
           res.redirect('/home');
        }
        res.send('ID or password wrong!');
    });
});

However, everytime when i get this error:

/opt/workspace/project/nodejs-demo/node_modules/mysql/lib/protocol/Parser.js:77
        throw err; // Rethrow non-MySQL errors
        ^

Error: Can't set headers after they are sent.
    at ServerResponse.OutgoingMessage.setHeader (_http_outgoing.js:344:11)
    at ServerResponse.header (/opt/workspace/project/nodejs-demo/node_modules/express/lib/response.js:718:10)
    at ServerResponse.send (/opt/workspace/project/nodejs-demo/node_modules/express/lib/response.js:163:12)
    at /opt/workspace/project/nodejs-demo/routes/index.js:40:7
    at Query._callback (/opt/workspace/project/nodejs-demo/modules/database.js:16:17)
    at Query.Sequence.end (/opt/workspace/project/nodejs-demo/node_modules/mysql/lib/protocol/sequences/Sequence.js:96:24)
    at Query._handleFinalResultPacket (/opt/workspace/project/nodejs-demo/node_modules/mysql/lib/protocol/sequences/Query.js:144:8)
    at Query.EofPacket (/opt/workspace/project/nodejs-demo/node_modules/mysql/lib/protocol/sequences/Query.js:128:8)
    at Protocol._parsePacket (/opt/workspace/project/nodejs-demo/node_modules/mysql/lib/protocol/Protocol.js:280:23)
    at Parser.write (/opt/workspace/project/nodejs-demo/node_modules/mysql/lib/protocol/Parser.js:73:12)

How to solve it? I do not know how to solve it and search for a long time. If i describe it not clearly, just comment and i will add anything i know.

Upvotes: 4

Views: 7910

Answers (3)

ZMath_lin
ZMath_lin

Reputation: 553

I should return in the if: 

if(req.body.password===manager.password)       
 {
    req.session.manager = manager;
    res.redirect('/home');
    return;
  }

Upvotes: 0

Ozgur
Ozgur

Reputation: 3766

I explained your problem in comments in code.

router.post('/login',function(req,res){ 
    var query = require('../modules/database');
    query("select * from managers where ManagerID =10001",function(err,vals,fields){  
        var temp=JSON.stringify(vals);

        var manager = JSON.parse(temp)[0];

        if(req.body.password===manager.password){
           req.session.manager = manager;


           //You are redirecting user to home
           res.redirect('/home');

           //You should add 'return'
           return;
        }

        //This will only accessible if password is not match
        res.send('ID or password wrong!');
    });
});

Upvotes: 1

Mukesh Sharma
Mukesh Sharma

Reputation: 9022

You have issues in the following snippet.

if(req.body.password===manager.password){
   req.session.manager = manager;
   res.redirect('/home');
}
res.send('ID or password wrong!');

It is clear from error stack trace that you are trying to set headers after it is being sent. It means that if statement executes first and if it true, it redirect to /home, after that it exits the if clause and tries to send message to user.

Possible Solution

if(req.body.password===manager.password){
   req.session.manager = manager;
   res.redirect('/home');
} else {
   res.send('ID or password wrong!');
}

Check it, if it helps you.

Upvotes: 0

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