Express with node

Question

I'm trying to return some rows from a db, connection works fine and everything but when express calls the function that retrieves the data it doesn't wait for the response.

I've tried many ways to write a callback to no avail, I've even tried using async (see code below), and it still runs all the way to the end before the data is even there. Any help?

router.get('/db/selectAllReadings', function(req, res) {
  async.waterfall([
    function(next){
      console.log('function 1');
      var rows = dbFunctions.selectAllReadings();
      next(rows);
    },
    function(next, rows){
      console.log('function 2');
      console.log(rows);
      next(rows);
    },
    function(next, rows){
      console.log('function 3');
      res.json(rows);
    }
  ]);
});

which function is fetching the data from the database.? – Ravi Shankar Bharti Dec 16 '16 at 10:14 — Ravi Shankar Bharti, Dec 16 '16 at 10:14
@ravishankar var rows = dbFunctions.selectAllReadings(); – Artemio Ramirez Dec 16 '16 at 10:16 — Artemio Ramirez, Dec 16 '16 at 10:16

score 0 · Answer 1 · answered Dec 16 '16 at 20:20

0

I finally managed it to work, thanks to @imran khan for helping me see things clearer.

router.get('/db/selectAllReadings', function(req, res) {
  dbFunctions.selectAllReadings(function(rows){
    res.json(rows);
  });
});

answered Dec 16 '16 at 20:20

Artemio Ramirez

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score -1 · Answer 2 · answered Dec 16 '16 at 14:13

router.get('/db/selectAllReadings', function(req, res) {
  async.waterfall([
    function(next){
      console.log('function 1');
      dbFunctions.selectAllReadings(function(err,data){
        if(err){
        }else{
          var rows = data;
          next(rows);
        }
      });

    },
    function(next, rows){
      console.log('function 2');
      console.log(rows);
      next(rows);
    },
    function(next, rows){
      console.log('function 3');
      res.json(rows);
    }
  ]);
});

//need to do little bit change in your dbFunction

if (err) {
            callback(err,null);
        }
        else if (data.length > 0) {
            callback(null,data);
        }

i hope u will get an better idea of it..

While your answer didn't quite work, it help me understand things better and finally make it work, thanks — Artemio Ramirez, Dec 16 '16 at 20:19

Express with node

2 Answers2