I am very new to backbone.js, to try it out I made a function to append an element using my array. But I don't know how to fetch the same from server or my local path.
I tried with some tutorial but still I couldn't get any good result. Can any one correct my function to fetch the data from local folder or server?
code :
this is my local path: '..data/data.json'
(function($){
var student = [
{name:'student1'},
{name:'student2'},
{name:'student3'}
]
var model = Backbone.Model.extend({
defaults:{
name:'default name'
}
});
var collection = Backbone.Collection.extend({
model:model
});
var itemViews = Backbone.View.extend({
tagname:'li',
render:function(){
this.$el.html(this.model.get('name'));
return this;
}
})
var view = Backbone.View.extend({
el: $("#contacts"),
initialize:function(){
this.collection = new collection(student);
this.render();
},
render:function(){
var that = this;
_.each(this.collection.models, function(item){
that.renderName(item);
})
},
renderName:function(item){
var itemView = new itemViews({model:item});
this.$el.append(itemView.render().el);
}
});
Collections have the url property which links to the url where the models can be fetched (in a proper JSON format of course).
If you have a RESTful API you can tie them directly to a collection on your backend.
In your case you can modify the collection definition as follows
var collection = Backbone.Collection.extend({
model:model,
url: '..data/data.json' //OR WHATEVER THE URL IS
});
Then when instantiating your collection you have to call the fetch() method to fill in the collection.
myCollection = new collection();
myCollection.fetch();
For more information see this post
Backbone will call GET, POST, DELETE, etc on that same url depending on what needs to be sent or received from the server. So if you are building the REST api, your controller or router should route the appropriate functions to those methods. See below for exact mapping:
create → POST /collection
read → GET /collection[/id]
update → PUT /collection/id
delete → DELETE /collection/id
As a side note, if you have no control over the JOSN that is returned from the server, you can format it in any format you like in the parse function.
parse: function(response) { return response.itemYouWantAdded; }
This would be the case if your server is returning an object within an object, such as twitter feeds.
Or you could simply populate the model from the response manually in the parse function
parse: function(response) { var tmpModel = {
item1:response.item1,
item2:response.item2
};
return tmpModel; }
Hope this helps.
You can set a URL for your model or for your collection. Then when you run fetch it will read your JSON straight into either a single model or a collection of models. So in your case, your collection might look like
var collection = Backbone.Collection.extend({
url: '..data/data.json',
model: model
});
collection.fetch(); // Could also use collection.reset()
You just need to make sure your JSON is formatted properly to match your model's attributes.
Related
var app = {};
var FoodModel = Backbone.Model.extend({
url: "http://localhost/food"
});
var FoodCollection = Backbone.Collection.extend({
model: FoodModel,
url: "http://localhost/food"
});
var FoodView = Backbone.View.extend({
render: function(){
console.log(this.model.toJSON());
}
});
app.FoodModel = new FoodModel();
app.FoodCollection = new FoodCollection;
app.FoodCollection.fetch();
var myView = new FoodView({model: app.FoodModel})
In this piece of code, the console.log always returns null for data in this.model
If console.log the collection it is full of data, how can i get this.model inside the view to reflect the data in the collection?
I'm not sure where your app is triggering FoodView.render(). It won't happen automatically when you instantiate FoodView and it won't happen when the json response triggers a callback to app.FoodCollection.fetch() unless you are manually calling that in a success callback. If you are doing this, your context may have been lost.
Also, there are a few typos in your code (app.FoodCollection = new FoodCollection();). If not, then can you provide the exact code? Please include whatever code is calling render()
Also, I'm not sure your view is being associated with your model. Try:
var FoodView = Backbone.View.extend({
model: FoodModel,
render: function(){
console.log(this.model.toJSON());
}
});
Otherwise, Backbone has no way of knowing what model you are referring to.
Im having trouble figuring out how to populate a model's attributes from the server and then add the populated model to a collection and have that collection rendered by a view. Here's the code I have:
var movieDetails = new cinephile.Models.MovieDetailsModel({ id: movie.get('id') });
this.collection.add(movieDetails);
Inside of the MovieDetailsModel:
cinephile.Models.MovieDetailsModel = Backbone.Model.extend({
url: function()
{
return '/cinephile/api/index.php?action=getMovieDetails&movieId=' + this.id;
},
initialize: function()
{
this.fetch();
}
});
And this.collection is just a collection with the model set to be a cinephile.Models.MovieDetailsModel
I am listening for items to be added to the collection and when they are, the following is executed:
displayMovie: function(movie)
{
var view = new cinephile.Views.MovieView({
model: movie,
className: 'movie clearfix',
template: JST['app/scripts/templates/MovieView.ejs'],
});
this.$("#my-movies").append(view.el);
},
MovieView looks like this:
cinephile.Views.MovieView = Backbone.View.extend({
initialize: function(options)
{
this.template = options.template;
this.render();
},
render : function()
{
this.$el.html(this.template(this.model.attributes));
return this;
},
});
The problem I have is that the template I'm using is trying to access an attribute of the model that is undefined. Im pretty sure it's undefined because the MoveDetailsModel hasn't finished fetching before the model is added to the collection and subsequently rendered to the view.
How can I solve this issue? I'd like to be able to create a MovieDetailsModel that takes in an id, use that id to get the movie details from the server and then add the populated model to a collection and then render that collection to the screen.
Any help is appreciated.
Backbone fetch returns a jqXHR object, which is a Deferred objects Promise.
When fetch is called, the attributes are not populated yet. Promise objects have a don
ejqXHR function, where a callback can be passed to be executed once the request is done.
I would recommend moving the fetch into another method not the constructor, because there You can return the jqXHR object and access its done function.
Here is an example:
var movieDetails = new cinephile.Models.MovieDetailsModel({ id: movie.get('id') });
var promise = movieDetails.fetch();
promise.done(function() {
var view = new cinephile.Views.MovieView({model: movieDetails});
view.render();
});
I need to query the database using a backbone collection. I have no idea how to do this. I assume that I need to set a url somewhere, but I don't know where that is. I apologize that this must be a very basic question, but I took a backbone course on CodeSchool.com and I still don't know where to begin.
This is the code that I have for the collection:
var NewCollection = Backbone.Collection.extend({
//INITIALIZE
initialize: function(){
_.bindAll(this);
// Bind global events
global_event_hub.bind('refresh_collection', this.on_request_refresh_collection);
}
// On refresh collection event
on_request_refresh_collection: function(query_args){
// This is where I am lost. I do not know how to take the "query_args"
// and use them to query the server and refresh the collection <------
}
})
The simple answer is you would define a URL property or function to your Backbone.Collection like so:
initialize: function() {
// Code
},
on_request_refresh_collection: function() {
// Code
},
url: 'myURL/whateverItIs'
OR
url: function() {
return 'moreComplex/' + whateverID + '/orWhatever/' + youWant;
}
After your URL function is defined all you would have to do is run a fetch() on that collection instance and it will use whatever you set your URL to.
EDIT ------- Making Collection Queries
So once you set the URL you can easily make queries using the native fetch() method.
fetch() takes an option called data:{} where you can send to the server your query arguments like so:
userCollection.fetch({
data: {
queryTerms: arrayOfTerms[], // Or whatever you want to send
page: userCollection.page, // Pagination data
length: userCollection.length // How many per page data
// The above are all just examples. You can make up your own data.properties
},
success: function() {
},
error: function() {
}
});
Then on your sever end you'd just want to make sure to get the parameters of your request and voila.
Hi i have a nested collection.
{"Categories":[{},{},{}],"Preference":[{},{},{}],"Users":[{},{},{}]}
Now what i what is to pass Categories to another collection, preference to another collection and users to another collection too. Is it still confusing? I've read that you can do this on a model but will it do the work? Any ideas?
If you have control over your backend, what you probably want to do is split the retrieval of the collection into three different Ajax calls:
var Categories = Backbone.Collection.extend({
url: "/categories"
});
var Preferences = Backbone.Collection.extend({
url: "/preferences"
});
var Users = Backbone.Collection.extend({
url: "/users"
});
var categories = new Categories();
categories.fetch();
...
If you can't change the routes on your server for some reason, then you can manually create the models by passing the arrays into the constructor:
var categories = new Categories(data["Categories"]);
If the data is in JSON format you can use jQuery to parse into a Javascript object:
jQuery.parseJSON(data);
I'm just beginning out on Backbone.js. Here's my code.
$(function(){
//Backbone Model
var Cat = Backbone.Model.extend({});
// create a collection
var CatCollection = Backbone.Collection.extend({
model: Cat,
url: 'http://localhost/cats/index.php/cats/index'
});
var catCollection = new CatCollection();
catCollection.fetch();
// Backbone view
var CatView = Backbone.View.extend({
el: $("#contents"),
initialize: function() {
this.render();
},
render: function() {
this.el.html(catCollection);
}
});
var catView = new CatView();
});
What I am doing is.
Create a backbone model
Create a collection using the model I created.
Fetch data from MySQL database - this returns a JSON data object.
Display the fetched data in the div "#contents".
On google Chrome, I can see that the "fetch()" method works, because I can see my JSON object returned as
[{"id":"1","name":"stella","age":"5"},{"id":"2","name":"Max","age":"2"}]
But if I do "alert(catCollection)" after the fetch, it displays "[object] [object]".
What is the best way of displaying this?
You should use the templates in JST array.
$(this.el).html($(JST["comments/item"](model.toJSON())));
"comments\item" is the template path and name
If you are using Rails, just use the Jammit and write templates with ERB (default) or Jade
The backbone.js documentation give an example like so:
alert(JSON.stringify(catCollection));
http://backbonejs.org/#Collection-toJSON
Use console.log.