upload-policy.txt

{"expiration": "20014-01-01T00:00:00Z",
  "conditions": [ 
    {"bucket": "www.keyboard-layout-editor.com"}, 
    ["starts-with", "$key", "layouts/"],
    {"acl": "public-read"},
    {"success_action_redirect": "http://www.keyboard-layout-editor.com"},
    {"Content-Type": "application/json"},
    ["content-length-range", 0, 8192]
  ]
}