在 Backbone 我怎样才能找到一个单一的模型？

我在 Backbone 有一个 Clock模型:

var Clock = Backbone.Model.extend({});

我正在尝试从 /clocks/123中获取最新的信息，我尝试了以下几种方法:

“类”级别的方法

Clock.fetch(123)
// TypeError: Object function (){ ... } has no method 'fetch'

创建一个实例，然后对其调用 fetch:

c = new Clock({id: 123})
c.fetch()
// Error: A 'url' property or function must be specified

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我尝试创建一个 AllClocks收集资源(尽管我在页面上不需要这样的东西) :

var AllClocks = Backbone.Collection.extend({
model: Clock,
url: '/clocks/'
});
var allClocks = new AllClocks();
allClocks.fetch(123);
// returns everything from /clocks/

我如何才能得到 一 API 支持的时钟？

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最佳答案

Your second approach is the approach I have used. Try adding the following to your Clock model:

url : function() {
var base = 'clocks';
if (this.isNew()) return base;
return base + (base.charAt(base.length - 1) == '/' ? '' : '/') + this.id;
},

This approach assumes that you have implemented controllers with the hashbang in your URL like so, http://www.mydomain.com/#clocks/123 , but it should work even if you haven't yet.

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I personally recommend, following the Model#url method documentation

model = new Model(id: 1)
view = new View(model: model)
collection = new Collection([model])
model.fetch()

in your collection remember to add the collection url:

url: "/models"

and in your View's initialize function do:

this.model.bind("change", this.render)

this way backbone will do an ajax request using this url:

"/models/1"

your model will be updated and the view rendered, without modifying Collection#url or Model#urlRoot

note: sorry this example came out in coffee script, but you can easily translate it to js adding var statements

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Try specifying urlRoot in the model:

From the docs:

var Book = Backbone.Model.extend({urlRoot : '/books'});
var solaris = new Book({id: "1083-lem-solaris"});
solaris.fetch();
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var Person = Backbone.Model.extend({urlRoot : '/person/details'});
var myName = new Person({id: "12345"});
myName.fetch();

As a result you make a Ajax request on the 

URL http://[domainName]/person/details/id

and you have the JSON response back.

Enjoiiii !!!

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...and do this if you don't want the trailing slash on the model urlRoot:

    url : function() {
return this.urlRoot + this.id;
},
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You probably should be accessing the object trough a collection and keeping it in the collection all the time. This is how to do it:

var AllClocks = Backbone.Collection.extend({
model: Clock,
url: '/clocks/'
});


var allClocks = new AllClocks();
my_clock = allClocks.add({id: 123});
my_clock.fetch()
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I want to use RESTful url,but I couldn't understand why 'postId' can't be added to base url.

var PostModel = Backbone.Model.extend({
urlRoot: 'getBlogPost',
defaults: {
postTitle: "defaultTitle",
postTime: "1970-01-01",
postContent: "defaultContent",
postAuthor: "anonymous"
}
});


var post = new PostModel({
postId: 1
});
alert(post.url());

Then I know only after I set 'idAttribute' as 'postId' in Model can I get the right url. like this:

var PostModel = Backbone.Model.extend({
idAttribute: 'postId',
urlRoot: 'getBlogPost',
defaults: {
postTitle: "defaultTitle",
postTime: "1970-01-01",
postContent: "defaultContent",
postAuthor: "anonymous"
}
});

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