var express = require('express');
var db = require('../db');
var router = express.Router();

//member/:
router.post('/', function(req, res, next) {
        console.log('/member');
        console.log(JSON.stringify(req.body, null, 2));
        var email = req.body.email;
        var username = req.body.username;
        var password = req.body.password;

        console.log("email: "+email+", username: "+username+", password: "+password);
        var sql = "INSERT INTO member(email, username, password) VALUES(?,?,?)";
        var input = [email, username, password];

        console.log("db before");

        try{
                console.log("db before2");
                db.get().query(sql, input, function(err, res){
                        console.log("db");
                        if(err){
                                console.log(JSON.stringify(err, null, 2));
                                res.json({message:"error",code:401,result:false});
                        }else {
                                console.log(JSON.stringify(res, null, 2,));
                                res.json({message:"Signed up successflly.", code:100, result:true});
                        }
                });
        }catch(e){
                console.log(e);
        }
});

...

const mariadb = require('mariadb');

var pool;

exports.connect = function(done){
  console.log("Trying to connect DB...");
  pool = mariadb.createPool({
    host: 'localhost',
    user: 'root',
    password: 'simple123SNS',
    database:"SimpleSNS",
    connectionLimit: 5 // Why 5 ???
  });

  pool.getConnection()
      .then(conn=>{
    console.log("DB connected. id: "+conn.threadId);
  conn.end(); //release to pool
}).catch(err=>{
    console.log("DB failed connection: "+err);
});
}

function makeToken(){
  console.log("makeToken()");
  var text="";
  var possible="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
  for(var i=0;i<32;i++){
    text+=possible.charAt(Math.floor(Math.random()*possible.length));
  }
  return text;
}

function dbHelper(){
  console.log("dbHelper()");
  this.emailRequest=function(email,num){
    console.log("emailRequest");
    pool.getConnection()
        .then(conn=>{
      conn.query("INSERT INTO email_verification(email, code) VALUES(?,?)",[email,num]);
    conn.end(); //release to pool
  })
  .catch(err=>{
      console.log("not connected due to error: "+err);
  });
  }

  this.verify=async function(email,num){
    console.log("verify");
    let conn;
    var result=false;
    try{
      conn=await pool.getConnection();
// within 3minutes
      const rows=await conn.query("SELECT count(*) FROM email_verificaiton WHERE email=? AND code=? AND req_time >= NOW() - INTERVAL 3 MINUTE",[email,num]);
      if(rows[0]["count(*)"]>0){
        result=true;
      }
    }catch(err){
      throw err;
    }finally{
      if(conn)conn.end();
    }
    return result;
  }

  this.verifyUpdate=function(email,num){
    console.log("verifyUpdate");
    pool.getConnection()
        .then(conn=>{
      conn.query("UPDATE email_verification SET status = 1 WHERE email=? AND code=?",[email,num]);
    conn.end(); //release to pool
  })
  .catch(err=>{
      console.log("not connected due to error: "+err);
  });
  }

  this.emailRegister=async function(email,pass,nick,devid){
    console.log("emailRegister");
    let conn;
    var result;
    try{
      conn=await pool.getConnection();
      var rows=await conn.query("SELECT count(*) FROM email_verification WHERE email=? AND status = 1",[email]);
      if(rows[0]["count(*)"]>0){
        rows=await conn.query("SELECT count(*) FROM member WHERE email=?",[email]);
        if(rows[0]["count(*)"]==0){
          var token=makeToken();
          rows=await conn.query("INSERT INTO member (email,password,username,device_id,login_method,token) VALUES(?,?,?,?,0,?)",[email,pass,nick,devid,token]);
          if(rows["affectedRows"]>0){
            result={result:true,code:200,message:"success",data:[{email:email,token:token}]};
          }else{
            result={result:false,code:401,message:"db error"};
          }
        }else{
          result={result:false,code:402,message:"already registered id"};
        }
      }else{
        result={result:false,code:403,meesage:"email not verified"};
      }
    }catch(err){
      throw err;
    }finally{
      if(conn)conn.end();
    }
    return result;
  }

  this.emailLogin=async function(email,pass,devid){
    console.log("emailLogin");
    let conn;
    var result;
    try{
      conn=await pool.getConnection();
      rows=await conn.query("SELECT * FROM member WHERE email=?",[email]);
      if(rows.length==1){
        if(rows[0]["password"]==pass){
          var token=makeToken();
          rows=await conn.query("UPDATE member SET device_id = ?, token = ? WHERE email=?",[devid,token,email]);
          console.log(rows)
          if(rows["affectedRows"]>0){
            result={result:true,message:"Sign up Success.",code:200,data:[{email:email,token:token}]};
          }else{
            result={result:false,message:"db error",code:401};
          }
        }else{
          result={result:false,message:"wrong password",code:402};
        }
      }else{
        result={result:false,message:"not registered id",code:403};
      }
    }catch(err){
      throw err;
    }finally{
      if(conn)conn.end();
    }
    return result;
  }
}

exports.get=function(){
  console.log("exports.get");
  return pool;
}
// module.exports = new dbHelper;

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var db = require('./db');

//var passport = require('./passport');
//var auth = require('./routes/auth');

var memberRouter = require('./routes/member');
var indexRouter = require('./routes/index');
var emailRouter = require('./routes/email');
var googleRouter = require('./routes/google');
var facebookRouter = require('./routes/facebook');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

db.connect(function(err){
        console.log(err);
        if(err){
                console.log('Unable to connect to MariaDB.');
                process.exit(1);
        }
});
...