在控制器中呈现JSON [英] Rendering JSON in controller

问题描述

我正在阅读一本书，并且在有关控制器的一章中谈到渲染内容时，对于JSON，它有一个这样的示例，但没有详细介绍，因此我无法弄清楚该示例的大图适合:

I was reading a book and in a chapter about Controllers when it talks about rendering stuff, for JSON it has an example like this but doesn't go in to details so I couldn't figure out the bigger picture that this example fits in:

render :json => @projects, :include => tasks

还有一些将JSONP与回调函数一起使用的示例:

And also some example with JSONP using it with callback functions:

render :json => @record, :callback => 'updateRecordDisplay'

有人可以解释这些吗?

推荐答案

您通常会返回 JSON ，因为:

A)您正在将部分/全部应用程序构建为单页应用程序(SPA)，并且需要客户端JavaScript能够提取其他数据而无需完全重新加载页面.

A) You are building part / all of your application as a Single Page Application (SPA) and you need your client-side JavaScript to be able to pull in additional data without fully reloading the page.

或

B)您正在构建供第三方使用的API，并且已决定使用JSON序列化数据.

B) You are building an API that third parties will be consuming and you have decided to use JSON to serialize your data.

_{或者，也许您正在吃自己的狗粮并同时做}

在两种情况下，render :json => some_data都会对提供的数据进行JSON验证.第二个示例中的:callback键需要更多说明(请参见下文)，但这是同一想法的另一种变体(以JavaScript可以轻松处理的方式返回数据.)

In both cases render :json => some_data will JSON-ify the provided data. The :callback key in the second example needs a bit more explaining (see below), but it is another variation on the same idea (returning data in a way that JavaScript can easily handle.)

JSONP(第二个示例)是解决相同起源政策的一种方法是每个浏览器内置安全性的一部分.如果您的API位于api.yoursite.com，并且将要从services.yoursite.com提供服务，则JavaScript(默认情况下)将无法从services向XMLHttpRequest(XHR-aka ajax)请求>.人们绕过该限制的方式(在跨源资源共享规范之前最终)是通过从服务器发送JSON数据(就好像是JavaScript而不是JSON )来完成的.因此，而不是发回:

JSONP (the second example) is a way of getting around the Same Origin Policy that is part of every browser's built-in security. If you have your API at api.yoursite.com and you will be serving your application off of services.yoursite.com your JavaScript will not (by default) be able to make XMLHttpRequest (XHR - aka ajax) requests from services to api. The way people have been sneaking around that limitation (before the Cross-Origin Resource Sharing spec was finalized) is by sending the JSON data over from the server as if it was JavaScript instead of JSON). Thus, rather than sending back:

{"name": "John", "age": 45}

服务器将发回邮件:

valueOfCallbackHere({"name": "John", "age": 45})

因此，客户端JS应用程序可以创建指向api.yoursite.com/your/endpoint?name=John的script标记，并具有名为的valueOfCallbackHere函数(必须在客户端JS中定义).另一个来源的数据.)

Thus, a client-side JS application could create a script tag pointing at api.yoursite.com/your/endpoint?name=John and have the valueOfCallbackHere function (which would have to be defined in the client-side JS) called with the data from this other origin.)

这篇关于在控制器中呈现JSON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！