tornado-problem-details 1.1.0

RFC-7807 Error Documents for Tornado

This library provides a version of tornado.web.RequestHandler.send_error that speaks application/problem+json instead of HTML. The easiest way to use this library is to inherit from problemdetails.ErrorWriter and raise problemdetails.Problem exceptions instead of HTTPError.

class MyHandler(problemdetails.ErrorWriter, web.RequestHandler):
   def get(self):
      if not self.do_something_hard():
         raise problemdetails.Problem(status_code=500,
                                      title='Failed to do_something_hard')

HTTP/1.1 500 Internal Server Error
Content-Type: application/problem+json

{
   "status": 500,
   "title": "Failed to do_something_hard",
   "type": "https://tools.ietf.org/html/rfc7231#section-6.6.1"
}

You can easily construct more substantial response documents by passing additional keyword parameters to the problemdetails.Problem initializer. They become top-level properties in the response document.

You can also call send_error directly and produce a response docuemnt. The following snippet produces the same output as the previous snippet.

class MyHandler(problemdetails.ErrorWriter, web.RequestHandler):
   def get(self):
      try:
         self.do_something_hard()
      except SomeException as error:
         self.send_error(500, title="Failed to do_something_hard")

The interface of tornado.web.RequestHandler.send_error is less expressive since keyword parameters may be swallowed by intervening code. The only parameters that are recognized are: instance, title, and type. Use the exception-based interface for more substantial documents.