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.
Related
Good morning guys. I have a little understanding problem with backbone.js. i have a javascript sdk from a backend as a service with some getter and setter methods to get datas from this platform.
I have load this javascript sdk with require.js an it´s work fine. Now i need to create some models that work with this getter and setter methods to get this data to my collection an finally to my view. I do not have any clue...maybe someone have the right idea for me.
This is my current model:
define(['jquery','underscore','backbone'], function($,_,Backbone) {
var holidayPerson = Backbone.Model.extend({
initialize: function() {
console.log("init model holidayPerson");
this.on("change", function(data) {
console.log("change model holidayPerson"+JSON.stringify(data));
});
}
});
return holidayPerson;
});
Actually i create an instance of my model in my view:
define(['jquery','underscore','backbone','text!tpl/dashboard.html','holidayPerson','apio'], function($,_,Backbone,tpl, holidayperson, apio) {
template = _.template(tpl);
var usermodel = new holidayperson();
var dashboardView = Backbone.View.extend({
id: 'givenname',
initialize: function() {
console.log("dashboard view load");
usermodel.on('change', this.render);
var user = new apio.User();
user.setUserName('xxx');
user.setPassword('xxx');
apio.Datastore.configureWithCredentials(user);
apio.employee.getemployees("firstName like \"jon\" and lastName like \"doe\"", {
onOk: function (objects) {
console.log("apio: " + JSON.stringify(objects));
usermodel.set({mail: objects[0]['data']['mail'],lastname: objects[0]['data']['lastName'], username: objects[0]['data']['userName'], superior: objects[0]['data']['superior']});
}
});
},
render: function() {
console.log("render dashboard view");
console.log(usermodel.get('mail'));
console.log(usermodel.get('lastname'));
this.$el.html(template());
return this;
}
});
return dashboardView;
});
I think this not the right way...can i override the getter and setter method from this model ? Or maybe the url function ? Anyone now what is the best practice ?
Thanks a lot :-)
First of all, make sure that your render operation is asynchronous, as your API call will be and the usermodel params won't be set until that operation completes. If you render method fires before that, it will render the empty usermodel, since the data will not be there yet.
Second, a model need not fetch its own data, in my opinion. If you are going to have multiple users, you could use a collection to hold those users and then override the collection's sync method to handle the fetching of data from the API, but if there's no collection, it seems logical to me to have a method that does the data fetching and setting thereafter, as you've done.
I am very new to backbone.js, to try it out I made a function to append an element using my array. But I don't know how to fetch the same from server or my local path.
I tried with some tutorial but still I couldn't get any good result. Can any one correct my function to fetch the data from local folder or server?
code :
this is my local path: '..data/data.json'
(function($){
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.
I'm building some JS to access Google places JS API using backbone. So far I'm really stuck with the model bindings.
I overrode 'fetch' to be able to use the Google API. The call to Google works just fine.
var Places = Backbone.Collection.extend({
model: Place,
fetch: function(options) {
// SNIPPET //
service = new google.maps.places.PlacesService(map);
service.nearbySearch(request, this.googlePlaceCallback);
// SNIPPET //
},
parse: function(response){
// nerver called
},
googlePlaceCallback: function(results, status) {
// I do something here and is properly called after Google returns a response
}
});
I also defined a very simple View:
var MapView = Backbone.View.extend({
initialize: function() {
this.model = new Places();
this.model.bind("reset", this.render, this);
this.model.fetch();
},
render : function () {
console.log( this.model.toJSON() );
}
});
I can't figure out how to populate the 'model'. Google returns the expected results, but I can set them to the backbone model. I there something I need to do in 'googlePlaceCallback'? I'll probably will need to override 'parse' also since Google results are not quite all interesting.
Assuming that results is a collection of the results you want, you should be able to implement the callback as follows:
googlePlaceCallback: function(results, status) {
this.add(results);
}
Since Places is a backbone Collection, you're just calling the following method in the above code: http://backbonejs.org/#Collection-add
You will also have to get the correct this reference inside the googlePlaceCallback function (you want this to be the Collection). One way to do that is to use Underscores bindAll method ( http://underscorejs.org/#bindAll ), which you can use to make sure all methods in the Backbone class have a this context of the Collection itself. You can do this on initialize as follows:
initialize: function() {
_.bindAll(this);
}
Also, the reason parse is not being called is because you are overriding fetch, and fetch calls parse. If you take a look at the annotated backbone code, you will be able to see the method call: http://backbonejs.org/docs/backbone.html
demo fiddle (with problem) http://jsfiddle.net/mjmitche/UJ4HN/19/
I have a collection defined like this
var Friends = Backbone.Collection.extend({
model: Friend,
localStorage: new Backbone.LocalStorage("friends-list")
});
As far as I'm aware, that's all I need to do to get local storage to work (in addition to including it below backbone.js)
One thing I wasn't sure about, does the name "friends-list" have to correspond to a DOM element? I'm trying to save the "friends-list" so I called it that in local storage, however, localstorage doesn't seem to require passing a class or an id.
Here's a fiddle where you can see what I'm trying to do http://jsfiddle.net/mjmitche/UJ4HN/19/
On my local site, I'm adding a couple friends, refreshing the page, but the friends are not re-appearing.
Update
I've also done the following in my code on my local site
console.log(Backbone.LocalStorage);
and it's not throwing an error.
My attempt to debug
I tried this code (taken from another SO answer) in the window.AppView but nothing came up in the console.
this.collection.fetch({}, {
success: function (model, response) {
console.log("success");
},
error: function (model, response) {
console.log("error");
}
})
From the fine manual:
Quite simply a localStorage adapter for Backbone. It's a drop-in replacement for Backbone.Sync() to handle saving to a localStorage database.
This LocalStorage plugin is just a replacement for Backbone.Sync so you still have to save your models and fetch your collections.
Since you're not saving anything, you never put anything into your LocalStorage database. You need to save your models:
showPrompt: function() {
var friend_name = prompt("Who is your friend?");
var friend_model = new Friend({
name: friend_name
});
//Add a new friend model to our friend collection
this.collection.add(friend_model);
friend_model.save(); // <------------- This is sort of important.
},
You might want to use the success and error callbacks on that friend_model.save() too.
Since you're not fetching anything, you don't initialize your collection with whatever is in your LocalStorage database. You need to call fetch on your collection and you probably want to bind render to its "reset" event:
initialize: function() {
_.bindAll(this, 'render', 'showPrompt');
this.collection = new Friends();
this.collection.bind('add', this.render);
this.collection.bind('reset', this.render);
this.collection.fetch();
},
You'll also need to update your render to be able to render the whole collection:
render: function() {
var $list = this.$('#friends-list');
$list.empty();
this.collection.each(function(m) {
var newFriend = new FriendView({ model: m });
$list.append(newFriend.render().el);
});
$list.sortable();
return this;
}
You could make this better by moving the "add one model's view" logic to a separate method and bind that method to the collection's "add" event.
And a stripped down and fixed up version of your fiddle: http://jsfiddle.net/ambiguous/haE9K/
I wish to read a whole database table to fill a Backbone.js Collection, before updating a View.
I am using fetch and listening to the reset event.
My problem is the reset event fires up before the http request is made to the server.
My question is: how can I render the view AFTER the data is received back from the server on a fetch?
Here is a jsfiddle showing the problem (with a debugger placed at reset):
http://jsfiddle.net/GhaPF/16/
The code:
$(document).ready(function() {
var Item = Backbone.Model.extend({
urlRoot : './items'
});
var ItemList = Backbone.Collection.extend({
model: Item,
url: './items/',
});
var ItemListView = Backbone.View.extend({
el: 'body',
initialize: function(myitemList) {
this.itemlist = myitemList;
this.itemlist.bind('reset', this.debuggThis());
},
debuggThis: function() {
debugger;
},
render: function() {
},
events: {
"keypress #new-item": "createOnEnter"
},
createOnEnter: function(e) {
}
});
$("#new-item").focus();
var itemlist = new ItemList();
var myitemListView = new ItemListView(itemlist);
itemlist.fetch();
});
The following code works, but it just doesn't feel like proper backbone.js (MVC) code since it would be placed outside of the View definition:
itemlist.fetch().complete(function(){
Maybe the issue is this line:
this.itemlist.bind('reset', this.debuggThis());
Should actually be:
this.itemlist.bind('reset', this.debuggThis);
Your debugThis function was getting run at the time you set up the listener for the 'reset' event - not when the event is triggered. This was telling JavaScript that you wanted debugThis to return a callback function instead of having debugThis "be" the callback function.
Also, orangewarp's comment about passing 'this' as the third parameter is probably relevant too. Sot it would end up as:
this.itemlist.bind('reset', this.debuggThis, this);
That's strange. When you fetch() the reset event should be triggered AFTER your collection is populated. So I'm thinking the phenomena that reset happens before the http request is fired up may not be what you think it is.
Instead of using the complete... you could always just use the success callback option like this:
itemlist.fetch({
success: function() {
// Whatever code you want to run.
itemlist.debuggThis();
}
});
Also, when binding your reset you probably want this:
this.itemlist.bind('reset', this.debuggThis, this);