I have a problem:
In Meteor, I would like to be able to first fetch data from mongodb and then be able to update/edit the fetched data before returning it to the template.
So for example I have movies in the database in the following format:
{ name: "...", released: "..." }
In the code i would do something like this:
var movie = Movies.findOne({name: "Inception"});
Then I would like to get and edit the "release" data from the movie -variable. How to do it?
Use a transform:
return Movies.find({}, {transform:function(movie) {
if(movie.release) movie.release = movie.release + " _ This has been appended to release".
return movie;
});
Related
i have two collections in my DB
const FastFood = mongoose.model("fast-food", foodSchema)
const Liquid = mongoose.model("liquid", foodSchema)
both of them have whole bunch of data inside. i want to get a data like:
{
fast-food: {
//data here
},
liquid: {
// data here
}
}
await FastFood.find({})this code returns only data in fast-food but i want all.i dont want to write one by one like
await FastFood.find({})
await Liquid.find({})
and so on.
is there any way of achieving this. smth like myDB.getallData() which return all data inside. Thank You!
Using mongoose by the way
Given the data structure below in firebase, i want to run a query to retrieve the blog 'efg'. I don't know the user id at this point.
{Users :
"1234567": {
name: 'Bob',
blogs: {
'abc':{..},
'zyx':{..}
}
},
"7654321": {
name: 'Frank',
blogs: {
'efg':{..},
'hij':{..}
}
}
}
The Firebase API only allows you to filter children one level deep (or with a known path) with its orderByChild and equalTo methods.
So without modifying/expanding your current data structure that just leaves the option to retrieve all data and filter it client-side:
var ref = firebase.database().ref('Users');
ref.once('value', function(snapshot) {
snapshot.forEach(function(userSnapshot) {
var blogs = userSnapshot.val().blogs;
var daBlog = blogs['efg'];
});
});
This is of course highly inefficient and won't scale when you have a non-trivial number of users/blogs.
So the common solution to that is to a so-called index to your tree that maps the key that you are looking for to the path where it resides:
{Blogs:
"abc": "1234567",
"zyx": "1234567",
"efg": "7654321",
"hij": "7654321"
}
Then you can quickly access the blog using:
var ref = firebase.database().ref();
ref.child('Blogs/efg').once('value', function(snapshot) {
var user = snapshot.val();
ref.child('Blogs/'+user+'/blogs').once('value', function(blogSnapshot) {
var daBlog = blogSnapshot.val();
});
});
You might also want to reconsider if you can restructure your data to better fit your use-case and Firebase's limitations. They have some good documentation on structuring your data, but the most important one for people new to NoSQL/hierarchical databases seems to be "avoid building nests".
Also see my answer on Firebase query if child of child contains a value for a good example. I'd also recommend reading about many-to-many relationships in Firebase, and this article on general NoSQL data modeling.
Given your current data structure you can retrieve the User that contains the blog post you are looking for.
const db = firebase.database()
const usersRef = db.ref('users')
const query = usersRef.orderByChild('blogs/efg').limitToLast(1)
query.once('value').then((ss) => {
console.log(ss.val()) //=> { '7654321': { blogs: {...}}}
})
You need to use limitToLast since Objects are sorted last when using orderByChild docs.
It's actually super easy - just use foreslash:
db.ref('Users').child("userid/name")
db.ref('Users').child("userid/blogs")
db.ref('Users').child("userid/blogs/abc")
No need of loops or anything more.
I have an iOS app using Cloud Firestore and have problems with updating the data. My goal is to add urls to a dictionary one by one, but all I get is rewritten one value. How should I use setData and updateData? Tried it different ways
storageRef.child("users/" + currentUser.value!.documentID + "/" + faceRef.documentID + ".jpg")
.putData(data!).observe(.success) { (snapshot) in
guard let downloadURL = snapshot.metadata?.downloadURL()?.absoluteString else { return }
let db = self.fsReference.document(self.currentUser.value!.documentID)
var dict = ["faces": ["": ""]]
dict["faces"] = ["newvalue\(downloadURL.hashValue)": downloadURL]
db.updateData(dict)
completion?()
Here's what I tried. Any advice would be nice, thanks in advance!
UPD: Tried to move my dictionary to subcollection, but after .collection("newCollection").document("newdocument") collection does not appear. What might be the problem?
So what I am seeing is you are using cloud storage to save profile pictures and you want to save each one of the urls those pictures. You need to understand that both setValue() and updateValue() do just about the same thing. A note with updateValue() is it will create that document if it doesn't already exist. So, when updating values in Firestore understand that it sets the value to what you give it, which can be misleading at first.
1st When updating any document start by getting the document first. If people are constantly updating different document you may want to consider using Firestore transactions: https://firebase.google.com/docs/firestore/manage-data/transactions#transactions
This will make sure that your data is updated correctly.
2nd Append the URL to the to the array, I am not how you set it up, but I would setup the firestore to look something like this
"users" = [
"unique_id = "{
"firstname": "John",
"lastname": "Doe",
"unique_id": "document_id_here"
"faces": [ {key: value} ]
}
]
When you serialize that object your faces object should be this [[String: Any]]
3rd, last step would be to get the document and update just that value
// Get the value in the completion with the data use this code
// Drill down to the property you want to update using the completion data ex.
var faces = completedData.faces
faces.append("[key: value]")
// Update the data back to firestore
let path = Firestore.firestore().collection("users").document("unique_user_id")
// Merging is so important. otherwise it will override your document
path.setData(["facesKey: faces"], merge: true) {(error in
if let error = error {
// good error handling here
}
// Successfully updated document
)}
I am not able to update my mongoose schema because of a CastERror, which makes sence, but I dont know how to solve it.
Trip Schema:
var TripSchema = new Schema({
name: String,
_users: [{type: Schema.Types.ObjectId, ref: 'User'}]
});
User Schema:
var UserSchema = new Schema({
name: String,
email: String,
});
in my html page i render a trip with the possibility to add new users to this trip, I retrieve the data by calling the findById method on the Schema:
exports.readById = function (request, result) {
Trip.findById(request.params.tripId).populate('_users').exec(function (error, trip) {
if (error) {
console.log('error getting trips');
} else {
console.log('found single trip: ' + trip);
result.json(trip);
}
})
};
this works find. In my ui i can add new users to the trip, here is the code:
var user = new UserService();
user.email = $scope.newMail;
user.$save(function(response){
trip._users.push(user._id);
trip.$update(function (response) {
console.log('OK - user ' + user.email + ' was linked to trip ' + trip.name);
// call for the updated document in database
this.readOne();
})
};
The Problem is that when I update my Schema the existing users in trip are populated, means stored as objects not id on the trip, the new user is stored as ObjectId in trip.
How can I make sure the populated users go back to ObjectId before I update? otherwise the update will fail with a CastError.
see here for error
I've been searching around for a graceful way to handle this without finding a satisfactory solution, or at least one I feel confident is what the mongoosejs folks had in mind when using populate. Nonetheless, here's the route I took:
First, I tried to separate adding to the list from saving. So in your example, move trip._users.push(user._id); out of the $save function. I put actions like this on the client side of things, since I want the UI to show the changes before I persist them.
Second, when adding the user, I kept working with the populated model -- that is, I don't push(user._id) but instead add the full user: push(user). This keeps the _users list consistent, since the ids of other users have already been replaced with their corresponding objects during population.
So now you should be working with a consistent list of populated users. In the server code, just before calling $update, I replace trip._users with a list of ObjectIds. In other words, "un-populate" _users:
user_ids = []
for (var i in trip._users){
/* it might be a good idea to do more validation here if you like, to make
* sure you don't have any naked userIds in this array already, as you would
*/in your original code.
user_ids.push(trip._users[i]._id);
}
trip._users = user_ids;
trip.$update(....
As I read through your example code again, it looks like the user you are adding to the trip might be a new user? I'm not sure if that's just a relic of your simplification for question purposes, but if not, you'll need to save the user first so mongo can assign an ObjectId before you can save the trip.
I have written an function which accepts an array, and in callback returns with an array of ObjectId. To do it asynchronously in NodeJS, I am using async.js. The function is like:
let converter = function(array, callback) {
let idArray;
async.each(array, function(item, itemCallback) {
idArray.push(item._id);
itemCallback();
}, function(err) {
callback(idArray);
})
};
This works totally fine with me, and I hope should work with you as well
I'm designing an API and also consuming it with Backbone.js. Part of the API will include search operations. For example when searching for cars, I might have something like:
http://api.mysite.com/search/cars?q=volvo
With backbone, I can see two options for consuming the results.
Option 1: A search is a Collection
var CarSearch = Backbone.Collection.extend({
model: Car,
initialize : function(models, options){
this.query = options.query;
},
url: function(){
return "http://api.mysite.com/search/cars?q="+this.query;
}
});
var volvos = new CarSearch([], {query:'volvo'});
volvos.fetch();
Option 2: A search is a Model, and the results are a Collection
var CarSearchResults = Backbone.Collection.extend({
model: Car
});
var CarSearch = Backbone.Model.extend({
defaults: {
"query":"",
"carSearchResults":null
},
url: function(){
return "http://api.mysite.com/search/cars?q="+this.get('query');
},
parse: function(resp,xhr){
resp.carSearchResults = new CarSearchResults(resp.carSearchResults);
return resp;
}
});
var volvoSearch = new CarSearch();
volvoSearch.set({query:'volvo'});
volvoSearch.save();
What are the advantages / disadvantages of these options? Is there a backbone-y way of designing this?
I'm leaning towards option 2 because it seems easier to add things to the response like pagination details, or a next url. But option 2 seems messier in a couple of ways. For example, would I generate an ID on the server for the search model when it is saved? Don't think I need to get that model by ID, deleting or updating it doesn't really make sense either cause I'm not persisting it.
i dont know if its a good practice,
but i use for my search the "data" option in the "fetch" method.
https://stackoverflow.com/a/6659501/1067061
Maybe it helps.
Good Luck!
EDIT
This is the right way to pass query parameters in your collections url,
The reference to the Docs shows how to pass the data attribute in fetch options, the data attribute is actually an object with key value pairs referring to query params and their values
I would go with option one. At least imo a model should correspond to a single search result and the collection to the entire set of search results. so if you search for volvo and there are 6 items returned, each item should be a model contained within your collection.
Now this will largely depend on how you are representing a result on your server. If say for instance you have car instances then you just do the search server side using the query and return the resulting objects as json. Then you can have the returned list be the collection of car models that match the criteria. but if you are planning on returning the query results some other way then you will have to think about how the model should represent the data
I would recommend using a collection, like in option 1, but without the need to define a new collection just for the search.
Take a look at my blog post about this here: http://willdemaine.ghost.io/restful-search-with-backbone/
var SearchableCollection = Backbone.Collection.extend({},{
search: function(query, options){
var search = $.Deferred();
options = options || {};
var collection = new this([], options);
collection.url = _.result(collection, 'url') + 'search?q=' + query;
var fetch = collection.fetch();
fetch.done(_.bind(function(){
Backbone.Events.trigger('search:done');
search.resolveWith(this, [collection]);
}, this));
fetch.fail(function(){
Backbone.Events.trigger('search:fail');
search.reject();
});
return search.promise();
}
});
Then you can do:
var Cars = SearchableCollection.extend({});
var findCars = Cars.search('volvo');
findCars.done(function(cars){
var carsView = new CarsView({
collection: cars
});
carsView.render();
});