Sinatra, JavaScript Cross-Domain Requests JSON

Question

I run a REST-API build on top of Sinatra. Now I want to write a jQuery Script that fetches data from the API.

Sinatra is told to response with JSON

befor         


        

Answer 1

Use JSONP (JSON with padding). There is a JSONP extension for Rack.

Basically, you'll call:

$.ajax({
  type: 'get',
  url: 'http://api.com/posts',
  dataType: 'jsonp',
  success: function(data) {
     // do something
  }
})

which translates to a request like:

http://api.com/posts?callback=someJSFunc

and your server will respond, e.g.:

someJSFunc({"json":"obj"});

Of course, clients can do JSONP requests without jQuery. The trick with JSONP is you serve scripts, which can be cross-domain, rather than pure JSON, with cannot.