[BXXPwg] Default per-channel content type

Greg Hudson ghudson@mit.edu
Wed, 13 Sep 2000 14:16:16 -0400 (EDT)


I think I have a reasonable compromise on the default content-type
issue:

	* If there is a default content type, it has to be reported
	  during channel creation.  It can't be implicit in the name
	  of the profile.

	* We say that a default content type SHOULD NOT be used, but
	  it MAY be used if the application is very sensitive to
	  per-message bandwidth overhead.

Some possible variations on which I have no strong opinion:

	* We could forbid the specification of a default content-type
	  except when the profile explicitly allows it, under the
	  assumption that creators of profiles are more likely to be
	  thoughtful than creators of implementations.

	* We could say that the content-type SHOULD be explicitly
	  specified in each message even if it is text/xml, again
	  unless the application is very sensitive to per-message
	  bandwidth overhead.  (But in that case, why are you using
	  XML?)

This compromise has the following properties:

	* Protocol tracing tools which have access to the entire TCP
	  stream always know the content type of each message.

	* Protocol tracing tools which only have access to parts of
	  the stream will usually know the content type of each
	  message (as long as they have whole messages), because it
	  will usually be specified explicitly.

	* If we go with the second variation, protocol tracing tools
	  will never be in the position of erroneously assuming that a
	  message has text/xml content.