Sinatra: how to respond with an image with the headings "content-type" => "image / jpeg"

Question

Example:

require 'sinatra'

get '/somekey' do
  headers('Content-Type' => "image/jpeg")
  ["http://upload.wikimedia.org/wikipedia/commons/2/23/Lake_mapourika_NZ.jpeg", "http://img.brothersoft.com/screenshots/softimage/j/jpeg_converter-4567-1.jpeg"].sample
end

I want to respond with an image that is not hosted on my server.

How do I know this?

Note: The link to the image is not secret (since it is posted on S3). It is for the site that identifiers are generated.

Checkout http://identico.in/[insert_any_key_here] . The reason is because I wanted the server to view if the image already exists on S3, use it, if not, generate it and then upload it to s3.

Note: If I did:

require "open-uri"
open ["http://upload.wikimedia.org/wikipedia/commons/2/23/Lake_mapourika_NZ.jpeg", "http://img.brothersoft.com/screenshots/softimage/j/jpeg_converter-4567-1.jpeg"].sample

, , , , , .

Answer 1

, , . send_file open('link') - .

require 'sinatra'
require 'open-uri'

get '/' do
  send_file open('http://upload.wikimedia.org/wikipedia/commons/2/23/Lake_mapourika_NZ.jpeg'),
        type: 'image/jpeg',
        disposition: 'inline'
end

, javascript, .

require 'sinatra'
get '/' do
  "<script>document.location = 'http://upload.wikimedia.org/wikipedia/commons/2/23/Lake_mapourika_NZ.jpeg'</script>
end