ZCCADCDEDB567ABAE643E15DCF0974E503Z 更新一个不存在的文档

Question

I have a function that should update a token, based on an user's email. The thing is, the following code returns a token even if there isn't any document with the specified email in the mongoDB database and the function return the response code 200 to my server function. I'd like to prevent the updating of the document (and any further actions) when the specified e-mail isn't in the database or i'd like to return some information (regardless of the response code) to prevent further code from executing.

const vnosZetona = (req,res) =>{
    if(!req.body.ePosta ){
        return res.status(400).json({
            "sporočilo": "Epošta uporabnika manjka! Parameter je obvezen"
        });
    }
    if(!(new RegExp("[a-z]{2}[0-9]{4}@student.uni-lj.si").test(req.body.ePosta))){
        return res.status(400).json({
            "sporočilo": "Izgleda da nisi študent UL! Hm, "
        });
    }
    var generiranZeton = generirajObnovitveniZeton();
    User
    .updateOne( {email: req.body.ePosta},
                { $set: {zetonZaObnavljanjeGesla:generiranZeton}},
                (napaka) => {
                    if(napaka){
                       return res.status(400).json(napaka);
                    }else{
                        return res.status(200).json({
                            zeton : generiranZeton,
                            "sporočilo" : "Žeton uspešno dodan."
                        });
                    }         
                }
    )
  
  };

Answer 1

So after a series of trials & errors I finally figured out what's really wrong. When I issued the query (whith an email which was not in any document) direcly into the mongoDB shell I got the following response:
{ "acknowledged": true, "matchedCount": 0, "modifiedCount": 0 }
The result clearly says that the wasn't any update ( modifiedCount is 0) but the query was still executing without any errors, so I had to "collect" that text and then continue the execution based on the "modifiedCount" value.

const vnosZetona = (req,res) =>{
     //check for errors and other stuff
    var generiranZeton = generirajObnovitveniZeton(); //generate random token
     User
    .updateOne( {email: req.body.ePosta},
                { $set: {zetonZaObnavljanjeGesla:generiranZeton}},
                (napaka, sporociloQueryja) => {
                    if(napaka){
                       return res.status(400).json(napaka);
                    }else{
                        return res.status(200).json({
                            zeton : generiranZeton,
                            status: JSON.stringify(sporociloQueryja),
                            //the field "status" returns the result mentioned above 
                            //although slightly different than  in the mongoDB shell:
                            //{"n":0,"nModified":0,"ok":1}
                            "sporočilo" : "Žeton uspešno dodan."
                        });
                    }         
                }
    );
    
  };

//The following code calls the API above when we complete the form on the page and hit submit
const posljiZahtevoZaObnovoGesla = async (req,res,next) =>{
    
    //check for a valid email address 
   
    try{
        let odgovor = await axios.put(apiParametri.streznik + "/api/uporabniki/vnosZetona",{
            ePosta : req.body.ePosta
        });

        if(odgovor.status == 200){
           
            //If the query had no errors,regardless if anything was updated
            // we read the data that was returned from the API -> 
            // with a nonexistent mail, the  "odgovor.data.status" equals "{"n":0,"nModified":0,"ok":1}"
            var o = JSON.parse(odgovor.data.status);
        
            if(o.nModified == 0){
                //nothing was modified, the no document with the specified email exists
                // the user gets redirected to registration form
                return res.redirect("/registracija");
            }
            //the code sends the instructions to the specified mail that exists in database
            //using nodemailer and redirects to user sign in
            res.redirect("/prijava");
        }
        else if (odgovor.status >= 400){
            res.status(odgovor.status).json(
                {"sporocilo": "Nekaj si zafrknil! Rollbackaj na začetno stanje!"}
            );
          
        }
    }catch(napaka){
        next(napaka);
    }
};