在node.js的express.js中使用jsonp

问题描述

我正在创建一个简单的JSON API，它使用node-js使用jsonp返回一个对象这是服务器端的代码:

I am creating a simple JSON API that just returns me an object using jsonp using node-jsHere is the code for server side :

app.get('/vit',function  (req,res,next) {
    res.type('application/json');
    res.jsonp(items);  //items is the object
});

在部署到nodejitsu并转到url/vit时，我得到了对象项.这意味着它可以在服务器端工作.

On deploying to nodejitsu , and going to url /vit i get the object items.That means its working on the server side.

我有一个另一个域，我想从这里使用jsonp获取此对象这是客户端代码:

I have another domain from where I wanna get this object using jsonpHeres the client-side code :

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
    $.getJSON('http://trial.jit.su/vit',function  (data) {
       console.log(data) ;
    });
</script>

但是我在控制台上收到以下错误:

But I get the following error on the console:

XMLHttpRequest cannot load http://trial.jit.su/vit. Origin http://jquer.in is not allowed by Access-Control-Allow-Origin.

好像我不了解Jsonp.

Seems like I have not understand Jsonp.

推荐答案

引用jQuery文档

http://api.jquery.com/jQuery.getJSON/

您需要一个带有问号的占位符的查询字符串参数.

You need a query string param with a question mark as placeholder.

并查看 http://trial.jit.su/vit 的响应，缺少回调函数.您只是返回不带P的纯JSON，例如如果网址包含?callback=bacon，则您的响应必须为

And looking at the response of http://trial.jit.su/vit you're missing the callback function. You're just returning plain JSON without the P, e.g. if the url contains ?callback=bacon your response needs to be

bacon({"your": "json string"});

但是只要您提供callback参数，express就会为您完成此操作.

But express will do this for you, as long as you supply a callback param.

所以只需更改以下内容:

So just change the following:

$.getJSON('http://trial.jit.su/vit?callback=?',function  (data) {
    console.log(data) ;
});

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