Mongoose Pre Command not working as Expected - node.js

Question

Hi I am New to Mongoose And trying to use pre command to Convert a given password in String to Hash values before saving it in the database. I am not Getting any Syntax error but my password is not getting converted into Hash IDS.
My Controller Code is as follows:
User.save(req.body,function(err,data){
if (err) {
res.json({
sucess:false,
exception:err
});
}
else{
res.json({
sucess:true,
User:data
});
}
});
User.pre('save',function(next){
bcrypt.genSalt(SALT_WORK_FACTOR, function(err, salt){
if(err){
return res.json({
success:false,
exception:err
});
}
bcrypt.hash(password, salt, function(err, hash) {
if(err){
return res.json({
success:false,
exception:err
});
}
password=hash;
});
});
next();
});
Using Node inspector I found out that command line is not entering the User.pre .So Can somebody let me know where I am making a mistake.

Answer 1

There's various things wrong with your code, the main part being that hooks should be attached to the schema and not the model, which seems to be what you're doing.
Also, it looks like you're trying to add a pre-save hook for every request, which is not how hooks are supposed to work: they should be declared just once, on the schema (as said above) and before you create the model.
The order should be similar to this:
var UserSchema = new mongoose.Schema(...);
UserSchema.pre('save', ...);
var User = mongoose.Model(UserSchema);
This means that you can't send an error response from your pre-save hook, as you're trying to do now, but you don't really want that anyway IMO (you should keep your Mongoose schema/models separated from your Express route handlers). Instead, catch any errors that are thrown during .save() and handle them there.
To give an idea on what a proper hook might look like, here's an example (I took a guess as to your User schema so it may be using the wrong field names):
UserSchema.pre('save', function(next) {
var document = this;
bcrypt.genSalt(SALT_WORK_FACTOR, function(err, salt) {
if (err) return next(err);
bcrypt.hash(document.password, salt, function(err, hash) {
if (err) return next(err);
document.password = hash;
next();
});
});
});