Question

Some JSON data services on the Internet are designed to be consumed only by servers and neglect the possibility of being consumed directly by a web-only app.

Due to cross-site concerns, such services would work if they either provided a JSONP format or enabled CORS support.

I want to make a little JavaScript tool that can call an online resource that only returns JSON and not , and does not support .

One example case was a single-page app I was making for which the only data source I could find didn’t provide CORS or JSONP. Being a single-page app, it had no server of its own so was subject to the same-origin policy.

What strategies are available in such cases?

Answer 1

**One way is to find a proxy that can access a JSON data source and then serve it to your web app transformed to work with JSON, CORS, or any other format that you can handle without worrying about cross-site concerns.

One such proxy is Yahoo’s “YQL”.

YQL supports both JSONP and CORS.

So if your browser also supports CORS you can think of it as a free JSON to JSON proxy server. If not, then it is also a free JSON to JSONP proxy:

Here’s an example of how I used it with jQuery:

$.getJSON("http://query.yahooapis.com/v1/public/yql",
  {
    q:      "select * from json where url=\"http://airportcode.riobard.com/airport/" + code + "?fmt=JSON\"",
    callback: gotJSON, // you don't even need this line if your browser supports CORS
    format: "json"
  },
  function(data){
    if (data.query.results) {
      /* do something with
        data.query.results.json.code
        data.query.results.json.name
        data.query.results.json.location
      */
    } else {
      /* no info for this code */
    }
  }
);

And a version on jsfiddle…