如何在Jquery Ajax中使用Json数据

Question

I have a URL, which gives response on browser: https://api.sandbox.paypal.com/retail/merchant/v1/locations

It gives:

{
    "errorCode": 600031,
    "message": "Missing access token",
    "developerMessage": "You must provide an access token when calling this API. It can be passed as either a header of the form \"Authorization: Bearer \" or as a query parameter called access_token.",
    "errorType": "oauth/missing_access_token",
    "correlationId": "4de95cd8aa090"
}

I tried this:

$.ajax({
    url: "https://api.sandbox.paypal.com/retail/merchant/v1/locations",
    dataType: 'json',
    type: 'POST',
    success: function (data) {

        console.log(data); 
        alert("success", data);
    },
    error: function (data) {
        alert("fail", data);
        console.log(data);
        alert("Sorry..Please try again later"); 
    },
});

But I am not getting the same response as I am getting on browser. I am getting error.

Please check here http://jsfiddle.net/ajitksharma/wehGy/

However while debugging on Browser console I got the error:

XMLHttpRequest cannot load https://api.sandbox.paypal.com/retail/merchant/v1/locations . No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.

Answer 1

You can make AJAX calls to a backend API which is on another domain, however, it needs to return JSONP format and not just JSON, otherwise you get and error. This is due to same origin policy: https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy .

This discussion may be helpful to understand JSONP: Can anyone explain what JSONP is, in layman terms?

Since you don't have control over PayPal's API and you can't ask them to return JSONP to you, these requests to PayPal's API need to be done from the server-side script of your application.

Answer 2

Running this from any other location, for example JSFiddle, will give you the Access-Control-Allow-Origin error since you're making a cross-domain request. Please read further about the same-origin policy .

As for the first error, its because your request needs an API key from paypal. See this page about getting an API key and making a simple request.

Answer 3

As Lisa Stoz and kaminari suggested it is not possible to call a service in another domain without some patch work. Now as you see the response when you hit that url via browser it says you need to add an extra header to your ajax request something like 'authorisation'