JSON使用JQuery获取请求（跨域）

Question

I'm trying to make a simple JSON get request to an API on a domain that I do not control.

My code is simply:

$(document).ready(function () {
        $.ajax({
            type: 'GET',
            url: 'http://pubapi.cryptsy.com/api.php?method=marketdatav2',
            success: function (data) {
                console.log(data);
            }
        });
});

But since that is a cross-domain request, I am getting this error in the Chrome Console:

XMLHttpRequest cannot load http://pubapi.cryptsy.com/api.php?method=marketdatav2. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://fiddle.jshell.net' is therefore not allowed access.

And when I try to add the parameter dataType: 'jsonp' the Console returns with this error:

Uncaught SyntaxError: Unexpected token :

But when I examine the Network tab in Chrome I see that under Headers the Status Code is 200 OK and I can actually see the full response in the Response tab, but the console is still showing the "Unexpected Token :" error and the JQuery JSON request is still failing.

Here's the JS Fiddle link: http://jsfiddle.net/6Qcq2/ You can see the same results

I have tried running the url on http://www.hurl.it and it shows me Status OK and the response as well, so I must be doing something wrong.

I've pretty much wasted the whole day trying to figure out how to get around this problem.

Your help is very much appreciated.

Answer 1

The response from the API is JSON, not JSONP, so just changing the data type doesn't help.

You can use a proxy that makes the request and turns the JSON into JSONP:

$(document).ready(function () {
    $.ajax({
        type: 'GET',
        url: 'http://jsonp.guffa.com/Proxy.ashx?url=pubapi.cryptsy.com%2fapi.php%3fmethod=marketdatav2',
        dataType: 'jsonp',
        success: function (data) {
            console.log(data);
        }
    });
});

Demo: http://jsfiddle.net/6Qcq2/1/

Answer 2

You need to setup some type of proxy script. Due to the Same-origin policy , you can't make an ajax call to a resource that is on an external domain. You can get around this by setting up a simple PHP script that will query the data for you. Then, you would point your ajax call to your script (which will be hosted on your domain). The content type for that resource is application/json, so telling jQuery the type is jsonp won't help you.

Answer 3

AJAX requests do not work cross-domain for security reasons. Since you're reading JSON data, you may be able to make JSONP work.

Answer 4

Shouldn't the jsonp response direct to a callback?

What is JSONP all about?