I am creating simple book library using backbone.js. Functionalities are very simple.
1.) Get All Books
2.) Get Particular Book (from server)
3.) Display Books
from the collection i can get all the books. But how can I get single book from server using Models ? I need to make ajax call to server to get the book details. since the details may update pretty soon (I don't want to get it from all books collection)
So far I created Views, Model, Collections as follows
var Book: Backbone.Model.extend({
defaults:{
name: "",
id: ""
}
});
var Library: Backbone.Collection.extend({
model: Book,
url: function(){
return "/books";
},
fetchBooks: function(){
fetch({
success: success_callback,
error: error_callback
});
},
fetchBook: function(bookId){
//how to get single book ?
}
});
How do I get single item from the server using my existing models and collections ?
If you need to use your Model outside the scope of a collection, you need to specify the urlRoot property:
var Book: Backbone.Model.extend({
defaults: {
name: ""
// ** See Note on Defaults below ...
},
urlRoot: "/books"
});
After that you can initialize the Model with a given ID and fetch it:
fetchBook: function(bookId){
var book = new Book({ id: bookId });
book.fetch({
success: function() {
console.log('Received book: ' + book.toJSON());
}
});
}
This will result in a GET request to `/books/{id}'. Assuming the server returns JSON, all your results will be populated as attributes on the book instance.
** NOTE on Defaults: You definitely shouldn't have an id default to an empty string, as Backbone uses the presence or absence of an id to determine if a model has been saved on the server or not. For instance if you ever use model.save(...), Backbone will issue a POST if the id does not exist, or a PUT if the id does exist.
Related
I have this Backbone.js model and view code, where I am trying to get a value from a text field, and fetch data from REST api based on this value. I am having problems modifying the base URL.
Model with base URL:
var TodoItem = Backbone.Model.extend({
urlRoot : 'http://localhost/Codeigniter/index.php/testcontroller',
initialize: function(){
this.set('id', 1);
},
defaults: {
name: '',
age: ''
}
});
var todoitem = new TodoItem({name: "name"});
Function where I am setting new URL:
getUrl: function(celebname){
var urlstr = "http://localhost/Codeigniter/index.php/testcontroller/getdatabasedata?searchvalue="+celebname;
return urlstr;
},
Function that fetches data from the REST api.
getdata: function (event) {
var celebname = $('#celebname').val();
this.model.set({name: celebname});
this.model.save({}, { urlRoot: this.getUrl(celebname)});
this.model.fetch();
},
At the moment I am getting this error:
GET http://localhost/Codeigniter/index.php/testcontroller/1
I cannot change the base url using the getURL function to search for the value from input field.Instead is using the base url and the id at the end.
If I am not setting out the ID in the initialize function of the model, then I get this error:
POST http://localhost/Codeigniter/index.php/testcontroller/getdatabasedata?searchvalue=Rome
From what I have read online this is because there is no id assigned to the model.
How can I get the input field value, build the URL, and fetch data using the GET method?
Thank you
Backbone works incredibly well with true RESTful APIs. Part of the issue here is that the API you have does not really map well with the Backbone model i.e. it's not exactly RESTful. As a result, you're going to have to resort to "hacks" to have the client and server get along. Dynamically modifying the route of a model is an example of one such hack.
What might help get you better answers is if you could elaborate a bit more on the use-case you have in mind.
From what I can tell, you're not really trying to persist a TodoItem. Rather, you're trying to pre-populate it with some base data. If this is true, then you really should not be doing a save -- you should just be doing a fetch.
getdata: function (event) {
var celebname = $('#celebname').val();
var id = this.model.id;
this.model.id = 'getdatabasedata';
this.model.fetch({data: {searchvalue: celebname}});
this.model.id = id;
}
Passing the data option will tell jQuery to use it as a query string param.
Again, this is very hacky and I would not recommend it, but it will accomplish what you're trying to do.
Using Backbone.js as a front-end framework for my Rails app. In terms of Rails models I have a Publication model and an Article model. Each publication is associated with many articles and each article only belongs to one publication. When the user decides to delete a publication I want all the associated articles also deleted. When I say deleted I mean removed from the database.
The following code works in terms of deleting the specified Publication from the database but does not work for deleting the associated articles:
// destroys the proper publication but still needs to update the view
delete_publication: function(id){
var publication = new SimpleGoogleReader.Models.Publication({id: id});
publication.fetch({
success: function(x){
}
});
publication.destroy();
var articles = new SimpleGoogleReader.Collections.Articles();
articles.fetch({
data: {publication_id: id},
success: function(x){
}
});
articles.destroy();
}
});
I also tried moving the articles.destroy() line inside the success function but that did not work either. I could be wrong but I think by the time I call the .destroy() function on articles I am no longer working with a Collection object. Am I going about this wrong? I want a Collection object just not containing every Model, only the specified ones.
Any ideas?
Have you tried to delete the articles first :
// destroys the proper publication but still needs to update the view
delete_publication: function(id){
var articles = new SimpleGoogleReader.Collections.Articles();
articles.fetch({
data: {publication_id: id},
success: function(x){
}
});
articles.reset(); // empty the collection
articles.sync(); // persist the state of the collection to the server
var publication = new SimpleGoogleReader.Models.Publication({id: id});
publication.fetch({
success: function(x){
}
});
publication.destroy();
}
});
HI my basic model which fetches data from server is working perfect. I want to implement a search feature. When user enters any data the request goes to browser and desired model is returned.
var Book = Backbone.Model.extend({
urlRoot: '/books'
});
render: function(options) {
books = new Book({id:options.name});
books.fetch();
}
where
name = "search/"+dynamic_data;
Request URL that is being formed when i pass --> 'life' in variable dynamic_data
http://host/path/search%2Flife
Request URL that i want
http://host/path/search/life
How can I encode/escape my string to achieve the desired result. I have tried escape(), encodeURI(), encodeURIComponents
A workaround to solve this is create one more model with urlRoot as /books/search and pass just name . I don't think this is correct. Should I use this ?
According to your additionnal precisions stating that life is actually a book name...
It looks like Backbone is better integrated with RESTful API's. In REST, your urls should not contain verbs and to search books, you would do a GET /books/?name=life.
In that case, you would only have to define a Backbone.Collection like:
var BooksCollection = Backbone.Collection.extend({
model: Book,
url: '/books'
});
The to fetch books:
var books = new BooksCollection();
books.fetch({data : {name: 'life'}}); //GET /books/?name=life
If you really want your search operation to target /search/:name, you will have to check the Backbone.Collection api, but I think you will want to look at http://backbonejs.org/#Sync
You could override your collection's sync method to something like:
Backbone.Collection.extend({
...
sync: function (method, model, options) {
//for read operations, call the search url
if (method === 'read') {
options.url = '/search/' + options.data.name;
delete options.data.name;
}
//call the default sync implementation
return Backbone.Collection.prototype.sync.apply(this, arguments);
}
});
In this cased calling books.fetch({data : {name: 'life'}}); will result in GET /books/life.
Here's a fiddle that shows the example.
this would work:
books = new Book({id:options.name}, {url: options.name));
decodeURIComponent() will decode http://host/path/search%2Flife to http://host/path/search/life.
I have the following Model:
window.MyModel = Backbone.Model.extend({
initialize: function(props){
this.url = props.url;
}
parse: function(){
// #override- parsing data fetched from URL
}
});
// instantiate
var mod = new MyModel({url: 'some/url/here'});
I use this global variable 'mod' to fetch some data into this model from backend.
// fetch
mod.fetch({
success: function(){ ...},
error: ...
});
All above works well....
My Issue: I want to reuse this model by changing resetting the url and call fetch but it does not update the url somehow. I have tried the following:
mod.fetch({
data: {url:'/some/other/url'},
postData: true,
success: function(){ //process data},
error: ...
});
mod.set({url: '/some/other/url'});
// called fetch() without data: and postData: attributes as mentioned in previous
How do I set the url for my model so that I could call fetch() and it fetches data from updated url? Am I missing something. Thanks for any pointers..
UPDATE 1: Basically, I am unable to get updated values if I did
model.set({url: 'new value'});
followed by
model.fetch();
'model' is a global variable. Creating a fresh instance of 'model' works:
model = new Model({url:'/some/other/url'});
model.fetch();
however, works as required. Does this mean that a model instance is permanently attached to a url and it cannot be reset?
ANSWER TO MY QUESTION in UPDATE 1 Model instance is not permanently attached to a url. It can be reset dynamically. Please read through #tkone's thorough explanation and then #fguillens' solution for a better understanding.
After have understood the #tkone 's explanation...
If you still want to have a dynamic Model.url you always can delay its construction to run time, try this:
window.MyModel = Backbone.Model.extend({
url: function(){
return this.instanceUrl;
},
initialize: function(props){
this.instanceUrl = props.url;
}
}
Well the answer here is that you want to do:
mod.url = '/some/other/url'
The URL isn't part of the instance of the model itself, but rather an attribute of the MyModel object that you're creating your model instance from. Therefore, you'd just set it like it was an normal JavaScript object property. set is used only when the data you're setting (or conversely getting with get) is actually an attribute of the data you want to send/receive from the server.
But why you're changing the URL is the question we should be asking. The idea behind Backbone's model/collection system is that you speak to a REST endpoint and each model has a corresponding endpoint.
Like you've got a blog and that blog has an "entry" object which is available at:
/rest/entry/
And you've got a Backbone model for Entry:
Entry = Backbone.Model.extend({urlBase: '/rest/entry'});
Now when you save or fetch Backbone knows how this works.
So like you're making a new model:
e = new Entry();
e.set({title: "my blog rulez", body: "this is the best blog evar!!!!1!!"});
e.save();
This would then make Backbone do an HTTP POST request to /rest/entry with the body:
{
"title": "my blog rulez",
"body": "this is the best blog evar!!!!1!!"
}
(When you do your mod.set({url: '/some/other/url'}); you're actually adding a field called url to the dataset, so the server would send "url": "/some/other/url" as part of that JSON POST body above:
{
"title": "my blog rulez",
"body": "this is the best blog evar!!!!1!!",
"url": "/some/other/url"
}
The server would then respond with an HTTP 200 (or 201) response with the same model, only with, like, say, and ID attached:
{
"id": 1,
"title": "my blog rulez",
"body": "this is the best blog evar!!!!1!!"
}
And that's not what you're looking for, right?)
Now you've got this model and it's got an ID. This means if you change it:
e.set('title', 'my blog is actually just ok');
e.save()
Backbone now makes an HTTP PUT request on /rest/entry/1 to update the resource on the server.
The server sees that you're talking about ID 1 on the /rest/entry/ endpoint, so knows to update an existing record (and send back an HTTP 200).
TL;DR
Don't change the URL, Backbone will. Make a new model for a new piece of data.
model.urlRoot = "/your/url"
OR
model.urlRoot = function(){ return "/your/url"; }
OR
model.url = "/your/url"
OR
model.url = function(){ return "/your/url"; }
Default 'url' property of a Backbone.Model object is as below. Backbone.js doc says:
Default URL for the model's representation on the server -- if you're using Backbone's restful methods, override this to change the endpoint that will be called.
url: function() {
var base = getValue(this, 'urlRoot') || getValue(this.collection, 'url') || urlError();
if (this.isNew()) return base;
return base + (base.charAt(base.length - 1) == '/' ? '' : '/') + encodeURIComponent(this.id);
},
Clearly, It first gets the value of urlRoot, if not available, it will look at the url of the collection to which model belongs. By defining urlRoot instead of url has an advantage of falling back to collection url in case urlRoot is null.
You can set url as option in fetch function, like this:
var mod = new MyModel();
mod.fetch({
url: '/some/other/url',
data: {}
});
I have an API that filters a set of objects based on the ID present in the URL, like so:
http://localhost:8000/api/v1/goal_update/?goal__id=12&format=json
I have a collection that does a GET request on the above URL. Here is the code for the collection:
var GoalUpdateList = Backbone.Collection.extend({
// Reference the Goal Update model
model: GoalUpdate,
// Do HTTP requests on this endpoint
url: function() {
return "http://localhost:8000/api/v1/goal_update/?goal__id=" + this.goal_id + "&format=json";
},
// Set the goal ID that the goal update list corresponds to
initialize: function(goal_id) {
this.goal_id = goal_id;
},
});
I want to pass in the ID when I create a new instance of the collection, so I created a view that has this code:
this.collection = new GoalUpdateList(this.model.get("id"));
It thinks that I am passing in model parameters, though. I am trying to pass in information that tells the collection what URL to use. So it runs the ID through a validate function and messes up the rest of the backbone code.
Backbone's collections expect model data as the first parameter, as you've already noted. But you can specify a second parameter as an object literal, like other Backbone objects. Just pass null or undefined as the first parameter, and then in your collection initialize method, get the options as the second parameter.
GoalUpdateList = Backbone.Collection.extend({
initialize: function(data, options){
this.goal_id = options.goal_id;
}
});
new GoalUpdateList(null, model.get("goal_id"));