nodejs: Async and find issues

Question

I have an array, and for each row I need to do findIfExist and save into mongodb. The code is here:

router.post('/namespaceUpload', function(req, res,next) {
   var data=req.body;
   var totalRows=data.allRows.length;

   var conceptObject ={};
   var existingConcept;

   for (var i=0;i<totalRows;i++){
        async.series([
            conceptPrepare,
            conceptFind,
            conceptSave,
            ], function (err, result) {
                    console.log('kraj');
                    res.json('Ok'); 
        });
    }

    function conceptPrepare(callback){
        conceptObject.name= data.allRows[i].name;
        conceptObject.user= data.userId;
        callback();
    }
    function conceptFind(callback){
        namespaces.find({name: conceptObject.name}, function(err, result) { 
        if (err)
            next(err);
        else {
            if (result.length==0){
                console.log('0');
                existingConcept='';
            } else {
                console.log(result.length);
                existingConcept=result[0];
            }
        }
        callback();
        });
    }


    function conceptSave(callback){
        var namespace = new namespaces();
        if (existingConcept==''){
            namespace.name=conceptObject.name;
            namespace.description=conceptObject.description;
            namespace.lastUpdate.user=conceptObject.user;
            namespace.save(function(err) {
            if (err)
             return next(err);
             callback();             
            })

        }

    }

So I Used async.series, but only last record is written in database as much times as many array members i have. Also, I get an error " Can't set headers after they are sent." Any idea?

Possible duplicate of [Node.js Error: Can't set headers after they are sent](http://stackoverflow.com/questions/7042340/node-js-error-cant-set-headers-after-they-are-sent) — alexmac, Apr 18 '16 at 22:54
@AlexanderMac I think the bigger issue here is the "loop control" and not realizing the concept that you send the response when the loop is complete. Actually only just [answered a similar issue](http://stackoverflow.com/a/36705570/2313887) within the last hour. That shows how to handle the flow and respond only when the loop is complete. — Neil Lunn, Apr 18 '16 at 23:58

score 0 · Answer 1 · answered Apr 18 '16 at 22:56

0

You're getting the Can't set headers after they are sent error message because you 're not allowed to return smtg eg : res.send,res.render more than one time but in your for loop, it goes totalRows times try to return one value at the end of the loop

answered Apr 18 '16 at 22:56

Akram Saouri

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nodejs: Async and find issues

1 Answers1