relative URIs in Location header

The old specification of HTTP defined the values of a Location header to be absolute URI's.

https://datatracker.ietf.org/doc/html/rfc2616#section-14.30

Location = "Location" ":" absoluteURI

Nowadays, because there are so many broken implementations, relative URI's seem to be allowed as well:

https://datatracker.ietf.org/doc/html/rfc7231#section-7.1.2

Location = URI-reference

Sometimes this leads to errors.

Wouldn't it be better if tornado completes the URI or at least give a chance to do it?

For example I expected self.reverse_url() to return an absolute URI or at least that self.redirect() does that for me.

useful would be to add:

    def reverse_absolute_url(self, name, *args):
        return self.request.protocol + "://" + self.request.host + self.reverse_url(name, *args)

Start by tracing the behavior of self.reverse_url() and self.redirect(), then compare their handling of relative Location values with the RFC 7231 and RFC 2616 references in the issue. Done requires an agreed approach for absolute or relative URI handling and corresponding behavior in the affected entry points.