Working on an API I want to do a full document update of a MongoDB object.
This is my current code that works but it feels wrong to have to delete the _id every time. Is there a better way to do this?
PutDoco : function(doco){
return new Promise(function(Resolve,Reject){
delete doco._id;
db.collection('docos').updateOne(
{"details.ID":doco.details.ID},
doco,
function(err,result){
if(err)
return Reject(err);
Resolve(result);
}
);
});
},
You can use replaceOne instead when replacing all contents of a document (besides _id which is immutable). And because replaceOne returns a promise if you don't pass it a callback, you can reduce your whole function down to:
return db.collection('docos').replaceOne({"details.ID":doco.details.ID}, doco);
However, it might be clearer (and faster) to find the document to replace using _id instead:
return db.collection('docos').replaceOne({_id: doco._id}, doco);
Related
When using Mongoose (with bluebird in my case, but using callbacks to illustrate), the following codes all return a document from the collection:
model.findOne({}, function(err, document) {
//returns a document
})
model.findOne(null, function(err, document) {
//returns a document
})
model.findOne([], function(err, document) {
//returns a document
})
I would like to know if and how I can disable this kind of behaviour, as it is becoming a liability to my code where I infer queries from data a user feeds into the system. Especially the null query returning a valid document worries me.
As of right now I check the input for being an non-empty, non-array, non-null object, but it's becoming a bit cumbersome at scale.
What would be the best way to exclude this behaviour?
Not sure if it is the best way to go about it, but right now I've settled on using a pre-hook on the model itself which checks for the _conditions property of the 'this' object (which I inferred from printing seems to hold the query object) to not be empty.
Inserting a self-defined object in the next functionality causes the Promise to reject in which the query was originally called from.
( _ is the underscore package)
//model.js
//model is a mongoose.Schema type in the following code
model.pre('findOne', function(next) {
var self = this
if (_.isEmpty(self._conditions)) {
next(mainErrors.malformedRequest)
} else {
next()
}
})
Save() giving me error like "Object has no method 'save'"
Country.update({id:req.param('country_id')},model).exec(function(err,cntry){
if(err) return res.json(err);
if(!cntry.image){
cntry.image = 'images/countries/'+filename;
cntry.save(function(err){ console.log(err)});
}
})
Any Idea about how to save model within update query . ??
Assuming you're using Waterline and sails-mongo, the issue here is that update returns an array (because you can update multiple records at once), and you're treating it like a single record. Try:
Country.update({id:req.param('country_id')},model).exec(function(err,cntry){
if(err) return res.json(err);
if(cntry.length === 0) {return res.notFound();}
if(!cntry[0].image){
cntry[0].image = 'images/countries/'+filename;
cntry[0].save(function(err){ console.log(err)});
}
});
This seems to me an odd bit of code, though; why not just check for the presence of image in model before doing Country.update and alter model (or a copy thereof) accordingly? That would save you an extra database call.
When using mongoose (3.8) to update the database directly the callback function receives 3 parameters, none of then is a mongoose object of the defined model. The parameters are:
err is the error if any occurred
numberAffected is the count of updated documents Mongo reported
rawResponse is the full response from Mongo
The right way is, first you fetch and then change the data:
Country.findOne({id: req.param('country_id')}, function (err, country) {
// do changes
})
Or using the update method, the way you intended:
Country.update({id: req.param('country_id'), image: {$exists: false}}, {image: newValue}, callback)
I have this:
exports.deleteSlide = function(data,callback){
customers.findOne(data.query,{'files.$':1},function(err,data2){
if(data2){
console.log(data2.files[0]);
data2.files[0].slides.splice((data.slide-1),1);
data2.files[0].markModified('slides');
data2.save(function(err,product,numberAffected){
if(numberAffected==1){
console.log("manifest saved");
var back={success:true};
console.log(product.files[0]);
callback(back);
return;
}
});
}
});
}
I get the "manifest saved" message and a callback with success being true.
When I do the console.log when I first find the data, and compare it with the console.log after I save the data, it looks like what I expect. I don't get any errors.
However, when I look at the database after running this code, it looks like nothing was ever changed. The element that I should have deleted, still appears?
What's wrong here?
EDIT:
For my query, I do {'name':'some string','files.name':'some string'}, and if the object is found, I get an array of files with one object in it.
I guess this is a subdoc.
I've looked around and it says the rules for saving subdocs are different than saving the entire collection, or rather, the subdocs are only applied when the root object is saved.
I've been going around this by grabbing the entire root object, then I do loops to find the actual subdoc I that I want, and after I manipulate that, I save the whole object.
Can I avoid doing this?
I'd probably just switch to using native drivers for this query as it is much simpler. (For that matter, I recently dropped mongoose on my primary project and am happy with the speed improvements.)
You can find documentation on getting access to the native collection elsewhere.
Following advice here:
https://stackoverflow.com/a/4588909/68567
customersNative.update(data.query, {$unset : {"slides.1" : 1 }}, function(err){
if(err) { return callback(err); }
customersNative.findAndModify(data.query, [],
{$pull: {'slides' : null } }, {safe: true, 'new' : true}, function(err, updated) {
//'updated' has new object
} );
});
I have streamlined this question for simplicity. Value is passed to the function, and if there is no document with {field1: value}, create that document; otherwise, call another function. However, this query will always find a document, or perhaps fires whatever_function() regardless. Why can I not get (!doc) to be true? This database is operative and queries/updates appropriately except for this issue.
db.doc.find({field1: value}, function(err, doc) {
if (!doc) {
db.doc.save({field1: value});
}
else {
whatever_function();
}
});
Find returns a cursor to the selected documents. Then, you should check that doc length is 0.
NodeJS + Express, MongoDB + Mongoose
I have a JSON feed where each record has a set of "venue" attributes (things like "venue name" "venue location" "venue phone" etc). I want to create a collection of all venues in the feed -- one instance of each venue, no dupes.
I loop through the JSON and test whether the venue exists in my venue collection. If it doesn't, save it.
jsonObj.events.forEach(function(element, index, array){
Venue.findOne({'name': element.vname}, function(err,doc){
if(doc == null){
var instance = new Venue();
instance.name = element.vname;
instance.location = element.location;
instance.phone = element.vphone;
instance.save();
}
}
}
Desired: A list of all venues (no dupes).
Result: Plenty of dupes in the venue collection.
Basically, the loop created a new Venue record for every record in the JSON feed.
I'm learning Node and its async qualities, so I believe the for loop finishes before even the first save() function finishes -- so the if statement is always checking against an empty collection. Console.logging backs this claim up.
I'm not sure how to rework this so that it performs the desired task. I've tried caolan's async module but I can't get it to help. There's a good chance I'm using incorrectly.
Thanks so much for pointing me in the right direction -- I've searched to no avail. If the async module is the right answer, I'd love your help with how to implement it in this specific case.
Thanks again!
Why not go the other way with it? You didn't say what your persistence layer is, but it looks like mongoose or possibly FastLegS. In either case, you can create a Unique Index on your Name field. Then, you can just try to save anything, and handle the error if it's a unique index violation.
Whatever you do, you must do as #Paul suggests and make a unique index in the database. That's the only way to ensure uniqueness.
But the main problem with your code is that in the instance.save() call, you need a callback that triggers the next iteration, otherwise the database will not have had time to save the new record. It's a race condition. You can solve that problem with caolan's forEachSeries function.
Alternatively, you could get an array of records already in the Venue collection that match an item in your JSON object, then filter the matches out of the object, then iteratively add each item left in the filtered JSON object. This will minimize the number of database operations by not trying to create duplicates in the first place.
Venue.find({'name': { $in: jsonObj.events.map(function(event){ return event.vname; }) }}, function (err, docs){
var existingVnames = docs.map(function(doc){ return doc.name; });
var filteredEvents = jsonObj.events.filter(function(event){
return existingVnames.indexOf(event.vname) === -1;
});
filteredEvents.forEach(function(event){
var venue = new Venue();
venue.name = event.vname;
venue.location = event.location;
venue.phone = event.vphone;
venue.save(function (err){
// Optionally, do some logging here, perhaps.
if (err) return console.error('Something went wrong!');
else return console.log('Successfully created new venue %s', venue.name);
});
});
});