Mongoose model.save() not persisting to database on update

Question

I am developing a mongoose / node.js / express app.

in my routes I am using express' app.param() method to get my model instance into the request - instead of fetching it in each controller action.

i got show and create actions working in my controller - however I am stuck implementing the update action.

here is my relevant controller code:

// mymodel-controller.js
var mongoose = require('mongoose')
var MyModel = mongoose.model('MyModel');
var utils = require('../../lib/utils');

"use strict";

exports.update = function (req, res, next) {

  var mymodel = req.mymodel;
  mymodel.set(req.body);
  mymodel.slug = utils.convertToSlug(req.body.title);

  mymodel.save(function(err, doc) {
    if (!err) {
      console.log('update successful');
       // here i see the correctly updated model in the console, however the db is not updated
      console.dir(doc); 
      return res.redirect('/mymodels/' + mymodel.slug);
    } else {
      console.error('update error', err);
      return res.render('mymodels/edit', {
        title: 'Edit Model',
        model: mymodel,
        errors: err.errors
      });
    }
  });
}

The strange thing is, the mongoose save goes through successfully, I don't get any error. I see 'update successful' and the correctly updated model printed on the console, but not persisted in the database. I tried also fetching the model manually before updating and saving it, instead of using app.param(..) but I had the same effect. Any idea what I am missing here?

update

this is the code where I set the req.mymodel - part of a longer routes file. In my show actions e.g. I also use req.mymodel to display it and it works fine so far.

/**
 * mymodel ROUTES
 */
app.param('mymodel', function(req, res, next, id){
  MyModel.findOne({ 'slug': id }, function(err, mymodel) {
    if (err) {
      next(err);
    } else if (mymodel) {
      req.mymodel = mymodel;
      next();
    } else {
      res.status(404).render('404', {title: "Not found", errorMessage: "The requested mymodel was not found."});
    }
  });
});
app.get('/mymodels',                 mymodelsController.index);
app.get('/mymodels/new',             mymodelsController.new);
app.post('/mymodels',                mymodelsController.create);
app.get('/mymodels/:mymodel',        mymodelsController.show);
app.get('/mymodels/:mymodel/edit',   mymodelsController.edit);
app.put('/mymodels/:mymodel',        mymodelsController.update); // that's the one not working with the code above
app.del('/mymodels/:mymodel',        mymodelsController.destroy);

update2

This code, on the other hand, works in my controller and updates the database (I'd much prefer using instance.save() though)

exports.update = function (req, res, next) {

  var mymodel = req.param('mymodel');


  var query = { slug: mymodel };

  var update = {};
  update.title = req.param('title');
  update.body = req.param('body');
  update.points = req.param('points');
  update.location = req.param('location');
  update.slug = utils.convertToSlug(req.param('title'));

  MyModel.update(query, update, function (err, numAffected) {
    if (err) return next(err);

    if (0 === numAffected) {
      return next(new Error('no model to modify'), null);
    }

    res.redirect('/mymodels/' + update.slug);
  });
}

Answer 1

The problem was indeed the way I set the req.param value in my routes.

Instead of doing this in my routes file:

app.param('mymodel', function(req, res, next, id){
  MyModel.findOne({ 'slug': id }, function(err, mymodel) {
    if (err) {
      next(err);
    } else if (mymodel) {
      req.mymodel = mymodel;
      next();
    } else {
      res.status(404).render('404', {title: "Not found", errorMessage: "The requested mymodel was not found."});
    }
  });
});

I had to declare a controller action that loads the instance each time, like

app.param('mymodel', mymodelController.load);

which pretty much looks like in this example.