Sails.js/Waterline populate deep nested association - javascript

I understand that there is no built-in way in Sails.js/Waterline of populating deep nested associations yet, so I am trying to use bluebird promises to accomplish that but I'm running into a problem.
I'm successfully retrieving the user, and all the posts (populated with the images collection) associated with it (console.log shows me that everything is filled properly). However, when I override the property "post" of the user and try to assign the fully populated posts retrieved before, it does not fill properly the images property of Post.js. It is like the ORM is preventing the image collection of Post.js to be manually assigned.
What am I doing wrong? What is the best way of populating deep nested one-to-many associations?
Bellow I've pasted all the code that I'm executing....
// Populate nested association
nested: function (req, res, next){
var username = req.param("id");
User
.findOneByUsername(username)
.populateAll()
.then(function (user){
var posts = Post.find({
"user": user.id
})
.populate('images')
.populate('category')
.then(function (posts){
return posts;
});
return [user, posts];
})
.spread(function (user, posts){
user.posts = posts; // This won't work.... It assigns all the fields properly but the images collection attribute
res.json(user);
}).catch(function (err){
if (err) return res.serverError(err);
});
}
// --- User.js Model --- //
module.exports = {
attributes: {
.....,
posts: {
collection: "post",
via: "user"
},
.....
}
}
// --- Post.js Model --- //
module.exports = {
attributes: {
....,
user: {
model: "user"
},
images: {
collection: "postImage",
via: "post"
},
....
}
}
// --- PostImage.js Model --- //
module.exports = {
attributes: {
....,
post: {
model: "post"
}
},
}
Regards,
Sávio Lucena

This might be an old question, but its better to have an answer, so sails.js users can benefit of it.
Your issue here is that when sails returns a record (Inside an array), the keys of that record that correspond to associations, are in fact getters/setters, and it seems that the setter does not allows what you want. You can use Object.getOwnPropertyDescriptor(user, 'posts') to confirm.
So what you need to do in order to be able to override that property as you want, is to call .toObject on it, (or clone its properties via _.clone or manually looping but you'll get a lot of junk with it, so stick to the .toObject), in any case you get a new object with the properties you need, and there is no restriction in how you modify it now.
So your code will look like this:
User
.findOneByUsername(username)
.populateAll()
.then(function (user){
var posts = Post.find({
"user": user.id
})
.populate('images')
.populate('category')
.then(function (posts){
return posts;
});
return [user, posts];
})
.spread(function (user, posts){
user = user.toObject() // <- HERE IS THE CHANGE!
user.posts = posts; // It will work now
res.json(user);
}).catch(function (err){
if (err) return res.serverError(err);
});
}

You have to overwrite each post id object in user.posts array. For more info check this answer https://stackoverflow.com/a/26452990/4261327.

Related

Creating new mongoose sub-doc and appending to existing parent doc

I'm building a website with a database using NodeJS, MongoDB, Express, Mongoose etc.
I have two schema set up: Events and a sub-doc schema Categories (among others).
The function pulls in array which contains the data needed to create several categories (this bit works) as well as the Event ID appended to the end.
The first few bits below just grab that ID, then remove it from the array (probably a better way to do this, but again, it works).
As mentioned above, the Categories then create correctly (and even do validation), which is amazing, BUT...
They don't get appended to the Event doc. The doc updates the "categories" field to an applicable number of "null" values, but I cannot for the life of me get it to actually take the IDs of the newly created categories.
I nabbed (and adjusted) the below code from somewhere, so this is where I'm at...
exports.addCategories = catchAsync(async (req, res, next) => {
const categories = req.body;
const length = categories.length;
const eventID = categories[length - 1].eventId;
categories.pop();
Event.findOne({ _id: eventID }, (err, event) => {
if (err) return res.status(400).send(err);
if (!event)
return res.status(400).send(new Error("Could not find that event"));
Category.create(categories, (err, category) => {
if (err) return res.status(400).send(err);
event.categories.push(category._id);
event.save((err) => {
if (err) return res.status(400).send(err);
res.status(200).json(category);
});
});
});
});
Currently the mongoose debug output is showing the following (which confirms that MOST of it is working, but the IDs just aren't being pulled correctly):
> Mongoose: events.updateOne({ _id: ObjectId("614bc221bc067e62e0790875")}, { '$push': { categories: { '$each': [ undefined ] } }, '$inc': { __v: 1 }}, { session: undefined })
Nevermind! I realised that "category" was still an array, rather than an element of the categories array as I'd assumed.
So I replaced that section with this, and now... it works!
Category.create(categories, (err, categories) => {
if (err) return res.status(400).send(err);
categories.forEach((category) => {
event.categories.push(category._id);
});
event.save((err) => {
if (err) return res.status(400).send(err);
});
});

Cannot Update / Add fields on an object in parse

I'm having a problem updating an object field with a key and a value on the user instance. The code runs successfully by saving but does not update the key on the object. Here is the code that I'm running
let query = new Parse.Query(Parse.User);
app.post("/saveListName", function (req, res) {
query.get(req.body.userObjectId, {
success: function (user) {
console.log(user);
user.set("list.foo", "Hello world"); //this is what I'm updating
user.save(null, {
useMasterKey: true
}).then(function (res) {
console.log("User saved");
console.log(res);
}).catch(function (err) {
console.log(err);
})
res.send(true);
},
error: function (err) {
console.log(err);
res.send(false);
}
})
})
foo is the key I'm trying to update on the list object. And I want to dynamically add new keys to the list object but not only one key. Please, I need help with this. I'm wondering if this feature(dynamically appending/removing fields on an object) is even supported in parse because going through documentation http://docs.parseplatform.org/js/guide/#updating-objects and I have not seen anything like that. Thanks

How to query all articles from a specific user?

CODE:
server-side
/**
* List of Articles
*/
exports.list = function (req, res) {
Article.find({ 'user.displayName': 'GIGANTOR !' }).sort('-created').populate('user', 'displayName').exec(function (err, articles) {
if (err) {
return res.status(422).send({
message: errorHandler.getErrorMessage(err)
});
} else {
res.json(articles);
}
});
};
SITUATION:
What I tried above does not work. I checked the mongoose docs: http://mongoosejs.com/docs/queries.html
but can't seem to get the query to work. Currently, the query just returns nothing.
QUESTION:
How to query all articles by a user with a specific displayName ?
TL;DR You can't query a document by a field that belongs to a populated object.
Since article simply has a ref to User, you'll have just get all articles, and then filter them in memory. Or, since the article.user field is an _id, you can find articles by the user ID (but your question is asking about finding them by user.displayName).
Mongoose populate does not do the populating in the MongoDB server itself; it populates on the application server. This means that multiple round-trips to the database are happening (see article Understanding Mongoose Population.) Therefore, you can't query by a field that exists as part of a populated object.
So, here's your 2 solutions:
Article.find({}).sort('-created').populate('user', 'displayName').exec(function (err, articles) {
if (err) {
return res.status(422).send({
message: errorHandler.getErrorMessage(err)
});
} else {
let filteredArticles = articles
.filter(article => article.user.displayName === 'GIGANTOR !');
res.json(filteredArticles);
}
});
Or, if you can query by _id, you can do this:
Article.find({ user: 'somemongoobjectidofuser' }).sort('-created').populate('user', 'displayName').exec(function (err, articles) {
if (err) {
return res.status(422).send({
message: errorHandler.getErrorMessage(err)
});
} else {
res.json(articles);
}
});
It gets to be a bit hairy and out of scope of the question, but another solution is the aggregation pipeline, which is only usually recommended for backend analytics. But, it'll provide you more flexibility in your query (especially if you user MongoDB's new $graphLookup).
Or, you can always store a copy of the user as a denormalized object inside the article document itself, but then you run into the much-discussed issue of maintaining denormalized documents in-sync.
Just putting the code I ended up using here for people who could need it:
/**
* List of Articles
*/
exports.list = function (req, res) {
Article.find({ user: req.user._id.toString() }).sort('-created').populate('user', 'displayName').exec(function (err, articles) {
if (err) {
return res.status(422).send({
message: errorHandler.getErrorMessage(err)
});
} else {
res.json(articles);
}
});
};

MongoDB - Save vs Update for specific fields in document

Using the MEAN stack, I'm attempting to have an admin account update another user's information, in this case, their title/role on the site. The problem I have is that the only function available when editing a user is the save() function. It might be that I can utilize the update function, and if that is the case please let me know, but it doesn't look possible:
The problem arises that when the user is saved, it creates a new document, and overwrites the user's password and salt to some value. I'd like to be able to call an "update" function that will only update the one field, but I can't figure out how to. Is there a way to do this with the save function?
Relevant Code:
exports.updateUserRoles = function(req, res) {
var currUser = req.body;
User.findById(currUser._id, function(err, user) {
//user.roles = currUser.roles;
user.save( { _id : '56467b28ba57d8d890242cfa', roles : 'admin' } );
//THE BELOW WAS A PREVIOUS ATTEMPT
/*user.save( function(err) {
if (err) {
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
} else {
res.jsonp(user);
console.log('test2');
}
});*/
});
};
Trying something else that seems very close, but still not quite there yet.
Here's what I'm running:
exports.updateUserRoles = function(req, res) {
var currUser = req.body;
User.findById(currUser._id, function(err, user) {
//user.roles = currUser.roles;
//user.roles.set(0, 'admin');
console.log('test');
user.update(
{ _id: '56467b28ba57d8d890242cfa' },
{
$set: {
roles: 'admin',
},
}
);
console.log('test2');
});
};
Upon hitting the user.update line, we have the user in the local variables, seen:
user.update goes into this Document.prototype.update function, seen:
The args look to be building right, which _id we are targeting and what the action is, seen:
But then after running, nothing seems to change. I'm very much stumped.
For updates various fields in mongodb you can use update with different atomic operators, like $set, $unset, $push etc.
Example:
var updateUserRoles = function(db, callback) {
db.collection('users').updateOne(
{ "_id", : "user_id", },
{ $set: { "password": "new_password" } },
function(err, results) {
console.log(results);
callback();
}
);
};

Node.js, MongDB (Mongoose) - Adding to data retrieved.

I currently have the following code:
User.find({ featuredMerchant: true })
.lean()
.limit(2)
.exec(function(err, users) {
if (err) {
console.log(err);
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
} else {
_.forEach(users, function(user){
_.forEach(user.userListings, function(listing){
Listing.find({
user: user
}).populate('listings', 'displayName merchantName userImageName hasUploadedImage').exec(function(err, listings){
user.listings = listings;
});
});
});
res.jsonp(users);
}
});
As you can see I am trying to add the retrieved listings to each 'user' in the 'users' lean object that I have returned. If I do a console.log(user) inside the Listing.find exec method after adding 'user.listings = listings', the result is as I would expect; a user object with a listings property, with this listing property containing all the listings retrieved.
However, if I console.log the 'users' object, the listings for each user cannot be found.
I'm pretty sure I'm doing something stupid here, but I really cannot work out what. Any help would be greatly appreciated. Thank you!
you right about stupid thing !
No offense, I think this is a common mistake :)
_.forEach(users, function(user){
_.forEach(user.userListings, function(listing){
Listing.find({
user: user
})
.populate('listings', 'displayName merchantName userImageName hasUploadedImage')
.exec(function(err, listings){
user.listings = listings;
});
});
});
// Listing.find inside foreach hasn't finish yet
// I suppose it's always an asynchronous call
res.jsonp(users);
Maybe you can fix it using promises. This an example with q library.
var promises = [];
_.forEach(users, function(user){
_.forEach(user.userListings, function(listing){
var deferred = q.defer();
promises.push(deferred);
Listing.find({
user: user
})
.populate('listings', 'displayName merchantName userImageName hasUploadedImage')
.exec(function(err, listings){
user.listings = listings;
deferred.resolve(user);
});
});
});
q
.all(promises)
.done(function(allUsers){
// Do what you want here with your users
res.jsonp(allUsers);
});
Check this and don't hesitate to fix it because I can't test it.
Thank you both for your input. It's truly appreciated. I managed to solve this an easier way which now I come to think of it is pretty obvious - but hey we live and learn. Basically, my 'userListings' model field was an array of Object Id's and I wanted to add the physical listings from the listings model into the data returned. The following code did the trick for me.
exports.findFeaturedMerchants = function(req, res, next) {
User.find({ featuredMerchant: true })
.populate('userListings')
.limit(2)
.exec(function(err, data) {
_.forEach(data, function(user){
Listing.populate(user.userListings, '', function(err, user){
if (err) {
console.log(err);
return res.status(400).send({
message: errorHandler.getErrorMessage(err)
});
}
});
});
console.log(data);
res.jsonp(data);
});
};
I simply had to populate each userListings object into the user, by using the populate function twice - once for the user and another time for each listing. I was finding it tricky to get my head around - probably because I didn't understand how the populate function worked exactly, but there we go :)
Jamie

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