mongoosejs upsert with on save hook - mongodb

Question

I'm trying to add data to my mongo database with mongoose, but there is a high probability that most of the data is already in the database, only a small number of fields need to be updated. Creation time for the record and last time updated need to be saved.
My first attempt at solving this problem included using the Model.save function, given that my model is called server, and data is an object coming from an external http service, which specifies the unique _id in data.
var instance = new Server(data);
instance.save(function(err){
if(err)
console.log(err);
});
also my pre-save hook:
ServerSchema.pre('save', function(next) {
this.lastseen = Date.now();
if (!this.isNew)
return next() //if the entry isn't new, lets not change the date registred
this.registered = Date.now();
next() //Don't forget this!
})
The problem here is that on duplicate _id the save chokes, with error E11000 duplicate key error index...
This now makes sense as save only does an update when the document instance is not created using the new operator.
So in my next attempt, I added code to attempt to lookup the document, then used underscore.js's _.extend to merge the new document with the one found in the database, then saved that to the database. The problem with this approach is that it require an extra call to the database for each chunk of data being processed.
My third attempt uses the Model.findByIdAndUpdate with {upsert:true} this works, in terms of stroring the data in the database, but schema defaults and my pre-save hook isn't triggered.
The fourth attempt uses code suggested by #aheckmann in this gist: https://gist.github.com/2764948
var server = new Server();
server.init(ping);
server.save(function(err){
if(err) {
console.log("DB Error: ",err);
return res.send('DB Error')
}
//if server approved, tell the inworld server to sync textures
if(server.approved)
res.send('success')
else
res.send('skip')
user.servers.addToSet(ping._id); //add the server to the user's list
user.save(function(err, usr){
if(err)
console.log("DB Error: ", err);
})
})
Here again, the pre-save hook isn't triggered. Am I to understand that the only to upsert with hooks is to attempt to find the document first with a findById ?
Q:
Is there a way to "upsert" Insert or Update based on the primary unique key without making more than one database call per chunk of data? Is there a method, or obvious fact that I am overlooking?

Answer 1

I don't think that you can do it with less then two calls to DB, unless you'll drop mongoose part and use mongo driver directly. But you can create a static method to do all the job for you:
ServerSchema.statics.findOrCreate(function(doc, next) {
this.findById(doc._id, function(err, res) {
res || (res = new this);
_.extend(res, doc); // add new data to the document
next(err, res); // if (err != null) then something went wrong
});
});
findByIdAndUpdate not triggers presave hook because it calls mongo driver directly.