Javascript 如何在 Backbone 中获取单个模型？

How do I fetch a single model in Backbone?

提问by James A. Rosen

I have a Clockmodel in Backbone:

我Clock在 Backbone 中有一个模型：

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

I'm trying to get an instance of that that has the latest information from /clocks/123. Some things I've tried:

我正在尝试从/clocks/123. 我尝试过的一些事情：

a "class"-level method

“类”级方法

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

creating an instance and then calling fetchon it:

创建一个实例然后调用fetch它：

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

a collection

一个集合

I tried creating an AllClockscollection resource (even though I have no use for such a thing on the page):

我尝试创建一个AllClocks集合资源（即使我在页面上没有使用这样的东西）：

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

How do I just get oneAPI-backed Clock?

我如何只获得一个API 支持的时钟？

采纳答案by Andrew De Andrade

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

您的第二种方法是我使用的方法。尝试将以下内容添加到您的时钟模型中：

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.

这种方法假设您已经在 URL 中实现了带有 hashbang 的控制器，如http://www.mydomain.com/#clocks/123，但即使您还没有，它也应该可以工作。

回答by Hernan S.

Try specifying urlRootin the model:

尝试在模型中指定urlRoot：

From the docs:

从文档：

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

回答by makevoid

I personally recommend, following the Model#url method documentation

我个人推荐，遵循Model#url 方法文档

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:

在您的收藏中记得添加收藏网址：

url: "/models"

and in your View's initialize function do:

并在您的视图的初始化函数中执行以下操作：

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

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

这样，主干将使用此 url 执行 ajax 请求：

"/models/1"

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

您的模型将被更新并呈现视图，而无需修改 Collection#url 或 Model#urlRoot

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

注意：对不起，这个例子是在咖啡脚本中出现的，但是您可以轻松地将其转换为 js 添加 var 语句

回答by Ankit Garg

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

因此，您在

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

and you have the JSON response back.

并且您返回了 JSON 响应。

Enjoiiii !!!

享受吧！！！

回答by 4m1r

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

...如果您不想在模型 urlRoot 上使用尾部斜杠，请执行此操作：

    url : function() {                        
        return this.urlRoot + this.id;
    },

回答by ssobczak

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:

您可能应该通过集合访问对象并始终将其保存在集合中。这是如何做到的：

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

var allClocks = new AllClocks();
my_clock = allClocks.add({id: 123});
my_clock.fetch()

回答by Araell

I want to use RESTful url,but I couldn't understand why 'postId' can't be added to base url.

我想使用 RESTful url，但我不明白为什么不能将“postId”添加到基本 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:

然后我知道只有在模型中将 'idAttribute' 设置为 'postId' 后，我才能获得正确的 url。像这样：

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