是什么VS urlRoot URL之间的区别 [英] What is the difference between url vs urlRoot

问题描述

我想知道什么是使用之间的网​​址或 urlRoot 的差异。我已阅读文档（ backbonejs.org/#Model-url ），但我还是觉得我缺乏知识，在这一领域我想知道更多。如果你有使用网​​址？而在另一种情况下你必须使用时， urlRoot ？

解决方案

.urlRoot 仅在模型可用，并且是唯一有用的当任一种模式是无法一部分集合，或当你想忽略它的模型是部分集合的的.url 属性。

在换句话说，一个模型不需要也不的.url 也不 .urlRoot 属性时，它的一部分以的.url 属性设置的集合，在这种情况下，这种模式将使用该集合的的.url ，因为它是自己的 .urlRoot 。

下面几个例子说明的差别。当您运行脚本，在HTTP请求中可以看到浏览器的网络面板。

的例1。的帖子不是集合的一部分。 urlRoot 定义网址的基本组成部分。当一个模型是牵强，它的ID被追加到 urlRoot 。

\r

\r

VAR邮政= Backbone.Model.extend（{\r
  urlRoot：H​​TTP：//jsonplaceholder.typi$c$c.com/posts\r
}）;\r
\r
VAR secondPost =新邮（{ID：2}）;\r
secondPost.fetch（）;\r
/ *请求HTTP：//jsonplaceholder.typi$c$c.com/posts/2 * /

\r

＆LT;脚本的src =HTTP：//$c$c.jquery。 COM / jquery.js和'＆GT;＆LT; / SCRIPT＆GT;\r
＆LT;脚本的src =HTTP：//underscorejs.org/underscore.js'>＆LT; / SCRIPT＆GT;\r
＆LT;脚本的src =HTTP：//backbonejs.org/backbone.js'>＆LT; / SCRIPT＆GT;

\r

\r

\r

的例2 的调用获取一个模型，它是一个集合的一部分，采用了集合的网​​址为 urlRoot

\r

\r

VAR邮政= Backbone.Model.extend（）;\r
VAR帖子= Backbone.Collection.extend（{\r
  网址：'HTTP：//jsonplaceholder.typi$c$c.com/posts'，\r
  型号：帖子\r
}）;\r
\r
VAR帖=新帖（）;\r
posts.add（{ID：2}）;\r
posts.first（）取（）。\r
/ *请求HTTP：//jsonplaceholder.typi$c$c.com/posts/2 * /

\r

＆LT;脚本的src =HTTP：//$c$c.jquery。 COM / jquery.js和'＆GT;＆LT; / SCRIPT＆GT;\r
＆LT;脚本的src =HTTP：//underscorejs.org/underscore.js'>＆LT; / SCRIPT＆GT;\r
＆LT;脚本的src =HTTP：//backbonejs.org/backbone.js'>＆LT; / SCRIPT＆GT;

\r

\r

\r

的例3。的网​​址设置模型将逐字将该网址用于任何模型的实例。

\r

\r

VAR邮政= Backbone.Model.extend（{\r
  网址：'HTTP：//jsonplaceholder.typi$c$c.com/posts\r
}）;\r
VAR secondPost =新邮（{ID：2}）;\r
secondPost.fetch（）;\r
/ *请求HTTP：//jsonplaceholder.typi$c$c.com/posts * /

\r

＆LT;脚本的src =HTTP：//$c$c.jquery。 COM / jquery.js和'＆GT;＆LT; / SCRIPT＆GT;\r
＆LT;脚本的src =HTTP：//underscorejs.org/underscore.js'>＆LT; / SCRIPT＆GT;\r
＆LT;脚本的src =HTTP：//backbonejs.org/backbone.js'>＆LT; / SCRIPT＆GT;

\r

\r

\r

的例4。的网​​址可以是一个功能，它开始再次意义。

\r

\r

VAR邮政= Backbone.Model.extend（{\r
  网址：函数（）{\r
    回归的http：//jsonplaceholder.typi$c$c.com/posts/'+ this.get（'塞'）;\r
  }\r
}）;\r
VAR secondPost =新邮（{弹头：2}）;\r
secondPost.fetch（）;\r
/ *请求HTTP：//jsonplaceholder.typi$c$c.com/posts/2 * /

\r

＆LT;脚本的src =HTTP：//$c$c.jquery。 COM / jquery.js和'＆GT;＆LT; / SCRIPT＆GT;\r
＆LT;脚本的src =HTTP：//underscorejs.org/underscore.js'>＆LT; / SCRIPT＆GT;\r
＆LT;脚本的src =HTTP：//backbonejs.org/backbone.js'>＆LT; / SCRIPT＆GT;

\r

\r

\r

I would like to know what is the difference between using url or urlRoot. I have read the documentation (backbonejs.org/#Model-url), but I still feel that I lack knowledge in this area and I would like to know more. When do you have to use url? And in another instance when do you have to use urlRoot?

解决方案

.urlRoot is only available in a Model, and is only useful when either a model is not part of a collection, or when you want to override the .url property of the collection which that model is part of.

In other words, a model doesn't require neither .url nor .urlRoot property when it is part of a collection with a .url property set, in which case this model will use that collection's .url as it's own .urlRoot.

Here are several examples that show the difference. When you run the scripts, the http requests can be seen in browser's network panel.

Example 1. Post is not part of a collection. urlRoot defines the base part of the url. When a model is fetched, it's id is appended to the urlRoot.

var Post = Backbone.Model.extend({
  urlRoot: 'http://jsonplaceholder.typicode.com/posts'
});

var secondPost = new Post({ id: 2 });
secondPost.fetch();
/*requests http://jsonplaceholder.typicode.com/posts/2 */

<script src='http://code.jquery.com/jquery.js'></script>
<script src='http://underscorejs.org/underscore.js'></script>
<script src='http://backbonejs.org/backbone.js'></script>

Example 2. Calling fetch on a model which is a part of a collection uses the collection's url as the urlRoot

var Post = Backbone.Model.extend();
var Posts = Backbone.Collection.extend({
  url: 'http://jsonplaceholder.typicode.com/posts',
  model: Post
});

var posts = new Posts();
posts.add({id: 2});
posts.first().fetch();
/*requests http://jsonplaceholder.typicode.com/posts/2 */

<script src='http://code.jquery.com/jquery.js'></script>
<script src='http://underscorejs.org/underscore.js'></script>
<script src='http://backbonejs.org/backbone.js'></script>

Example 3. url set on a model will literally use that url for any model instance.

var Post = Backbone.Model.extend({
  url: 'http://jsonplaceholder.typicode.com/posts'
});
var secondPost = new Post({ id: 2 });
secondPost.fetch();
/*requests http://jsonplaceholder.typicode.com/posts */

<script src='http://code.jquery.com/jquery.js'></script>
<script src='http://underscorejs.org/underscore.js'></script>
<script src='http://backbonejs.org/backbone.js'></script>

Example 4. url can be a function and it starts to make sense again.

var Post = Backbone.Model.extend({
  url: function(){
    return 'http://jsonplaceholder.typicode.com/posts/' + this.get('slug');
  }
});
var secondPost = new Post({ slug: 2 });
secondPost.fetch();
/*requests http://jsonplaceholder.typicode.com/posts/2 */

<script src='http://code.jquery.com/jquery.js'></script>
<script src='http://underscorejs.org/underscore.js'></script>
<script src='http://backbonejs.org/backbone.js'></script>

这篇关于是什么VS urlRoot URL之间的区别的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！