POST JSON response to HTTP request in Ruby - ruby

Question

I'm running a Ruby app on Heroku. The app returns a JSON which is accessible when I go to the debugger of my browser. The JSON response is of the following template:
rates = {
"Aluminium" => price[1],
"Copper" => price_cu[1],
"Lead" => price_pb[1],
"Nickel" => price_ni[1],
"Tin" => price_sn[1],
"Zinc" => price_zn[1],
}
Sample response:
{
"Aluminium":"1765.50",
"Copper":"7379.00",
"Lead":"2175.00",
"Nickel":"14590.00",
"Tin":"22375.00",
"Zinc":"2067.00"
}
the code i wrote to achieve this is:
Test.rb
class FooRunner
def self.run!
#calculations_for_rates
rates.to_json
end
if __FILE__ == $0
puts FooRunner.run!
end
app.rb
require 'sinatra'
require './test.rb'
result = FooRunner.run!
File.open('output.json','w') do |f|
f.write result
end
content_type :json
result
When I try to access this link using
$.getJSON('app-url',function(data){
console.log(data);
});
it gives me an error saying
No 'Access-Control-Allow-Origin' header is present on the requested resource.
Is there a way for me to directly access the JSON response by writing the JSON to the HTTP response?

Answer 1

So I am guessing that the page you are making the get request from is not served up by Sinatra. You can add the header Access-Control-Allow-Origin: * to that request to make it work.
This answer shows how to do it by either using response['Access-Control-Allow-Origin'] = * or headers( "Access-Control-Allow-Origin" => "*" )
That answer also lists this blog post as a reference to Cross Origin Resource Sharing in Sinatra.