Socket.io and Node.js with mysql not returning results as expeted -

edit: i'm rephrasing question: socket.io not waiting callback , connection never accepted. please see edit 2/attempt 1 below

this check authentication token against database. can spot wrong here?

var checkauth = function(auth) {     var rs = 0;     var sql = 'select * clients pword=\''+auth+'\'';      // copied debug session , got results: select * clients pword='d98e623c7a74a178703d17e1fd536b1488724acd41e71f178331c768c385bda2c82d2bcb60cbb4650be375ad4734c63fb694bd164c138f9abe0c51f37f9a7e33'     var query = connection.query(sql);     query         .on('error', function(err) {             console.log( err );         })         .on('result', function( row ) {             rs = number(row.client_id); // never fires!!?!?!         })         .on('end',function(){          });     if (rs == 0) {         sql = 'select * users pword=\''+auth+'\'';         query = connection.query(sql);         query             .on('error', function(err) {                 console.log( err );             })             .on('result', function( row ) {                 rs = number(row.client_id); // never fires!!?!?!             })             .on('end',function(){             });     }     return rs; } 

edit 1: use follwoing loop authenticate socket.io connections runs function, ok understand have wait db finish, put callback?

io.use(function(socket, next){     console.log("query: ", socket.handshake.query);     // return result of next() accept connection.     socket.clientid = 0;     socket.clientid = checkauth(socket.handshake.query.auth);     console.log("cid:"+socket.clientid);     if (socket.clientid != 0) {         return next();     }     // call next() error if need reject connection.     next(new error('authentication error')); }); 

edit 2/ attempt 1 according johannes' suggest:

var checkauth = function(auth, cb) {     var rs = 0;     var sql = 'select * clients pword=?';     var query = connection.query(sql, [auth]);     query         .on('error', function(err) {             console.log(err);         })         .on('result', function(row) {             rs = number(row.client_id);         })         .on('end', function() {             if (rs == 0) {                 sql = 'select * users pword=?';                 query = connection.query(sql, [auth]);                 query                     .on('error', function(err) {                         console.log(err);                     })                     .on('result', function(row) {                         rs = number(row.client_id);                     })                     .on('end', function() {                         cb(rs);                     });             }         }); }  io.use(function(socket, next){     console.log("query: ", socket.handshake.query);     // return result of next() accept connection.     socket.clientid = 0;     var auth = socket.handshake.query.auth;      checkauth(auth, function(clientid){         socket.clientid = clientid;         if (clientid != 0) {             return next();         }         console.log('clienid', clientid);         next(new error('authentication error'));     });      // if (socket.clientid != 0) {     //     return next();     // }     // // call next() error if need reject connection.     // next(new error('authentication error')); }); 

this whole process async. have 2 things:

move event callback , add callback or promise checkauth function. should escape inserted data.

edited solution

var checkauth = function(auth, cb) {     var rs = 0;     var sql = 'select * clients pword=?';     var query = connection.query(sql, [auth], (err, client) => {         if(err || !client || client.length < 1) return cb(err || new error('unkown client'));          sql = 'select * users pword=?';         query = connection.query(sql, [auth], (err, user) => {             if(err || !user || user.length < 1) return cb(err || new error('unkown user'));             cb(null, client[0].client_id);         });     }); } 

note: why doing 2 queries in first place , storing password each client of user?

original answer:

var checkauth = function(auth, cb) {     var rs = 0;     var sql = 'select * clients pword=?';     var query = connection.query(sql, [auth]);     query         .on('error', function(err) {             console.log(err);         })         .on('result', function(row) {             rs = number(row.client_id); // never fires!!?!?!         })         .on('end', function() {             if (rs == 0) {                 sql = 'select * users pword=?';                 query = connection.query(sql, [auth]);                 query                     .on('error', function(err) {                         console.log(err);                     })                     .on('result', function(row) {                         rs = number(row.client_id); // never fires!!?!?!                     })                     .on('end', function() {                         cb(rs);                     });             }         }); }  checkauth(123, function(clientid){     console.log('clienid', clientid); });