Express return post

Question

Good afternoon,

I am having a problem in the return of POST on express, I wanted to register users using the following code :

router.post('/user', (req,res,next) =>{

  var obj =   {name:req.body.des_name,
              email:req.body.des_email,
              endereco:req.body.des_endereco,
              cep:req.body.num_cep,
              phone:req.body.num_phone,
              password:req.body.des_password}



        user.verifyUserTest(obj.name, function(err, rows) {
             if (rows.length > 0){
               res.send({res : "usuário já cadastrado"})
             }
             else{
              user.setUserByParams(obj,res)
              next()
              }
         })

},Function(obj,res){

res.send("ok")

})

I need to catch the return of VerifyUser to make an if if if user exists display an error message, and if it does not exist it calls the next by passing Obj as parameter so that the other function setUserByParams enter the user in the database.

the problem is that the console.log(user.verifyUser(obj,res)) is returning Undefined and I needed it to return the user or a full value of what I send to the POST

the other methods:

Midleware

function verifyUser(req,res){

  return con.query(`SELECT * FROM TB_USER WHERE des_name like "${req.name}"`,res)
}

Database/Query:

function query(sqlQry,res){
  connection.query(sqlQry,function (err,results,fields) {
    if(err){
      res.json(err)
    }else{
      console.log("Query Executada: "+ JSON.stringify(results))
      res.json(results)

    }
  })
}

Detail that the post sending and execution of the method is ok because it returns me the objects containing the user in POSTMAN including I put a log in the query (query executed:) that is returning me the query result correctly.

I appreciate the help, thank you!.

Code setUsersByParams:

function setUserByParams(req,res){

  return con.query(`INSERT INTO db_lifeapp.tb_user (des_name,
                                                    des_email,
                                                    des_endereco,
                                                    num_cep,
                                                    num_phone,
                                                    des_password)
                          VALUES ('${req.name}',
                                  '${req.email}',
                                  '${req.endereco}',
                                  ${req.cep},
                                  ${req.phone},
                                  '${req.password}')`,res)

      }

Uses the same database query call.

Answer 1

You have to create asynchronous logic in that middleware to wait for the comic’s answer before calling the next. You can do it like this:

router.post('/user', (req, res, next) => {
  var obj = {
    name: req.body.des_name,
    email: req.body.des_email,
    endereco: req.body.des_endereco,
    cep: req.body.num_cep,
    phone: req.body.num_phone,
    password: req.body.des_password
  }

  user.verifyUser(obj.name, function(err, rows) {
    if (rows.length > 0) next();
    else user.setUserByParams(req, next)
  })
}, function(req, res){
   // esta função corre quando o `next` anterior for chamado 
   // e aqui o utilizador já estava ou está agora registado
   res.send('Ok!');
});

function verifyUser(name, cb) {
  con.query(`SELECT * FROM TB_USER WHERE des_name like "${name}"`, cb)
}

function query(sqlQry, cb) {
  connection.query(sqlQry, cb)
}

function setUserByParams(obj, cb) {
  con.query(`
    INSERT INTO db_lifeapp.tb_user (
       des_name, des_email, des_endereco, num_cep, num_phone, des_password
    ) VALUES (
      '${obj.name}', '${obj.email}', '${obj.endereco}', ${obj.cep}, ${obj.phone}, '${obj.password}')`, cb)
}

I think the logic of your code limits you.

So I changed my answer. What you have (in question) is the answer of this SELECT to be solved within dat function query with res.json(results) and so does not allow what you need.

Who should treat this result is the function that calls the query, because the funçãoquery` should be "blind" and only do what you are asked and return the result.