xml-dev - RE: Binary XML

["Arnold, Curt" <Curt.Arnold@hyprotech.com>]

There has a been a decent amount of debate on the Xerces-J-dev mailing list in the last few months over proposed Requirement 39  (http://xml.apache.org/xerces-j/issues.html#req.39) for Xerces 2:

The parser should allow for automatic detection of compressed/encrypted documents.

Unfortunately, the mailing list archive is having its own problems, so I can't give you links to any of the significant postings.

Basically, my idea when I proposed it was that in the event that a binary stream was not recognized as any supported encoding family, then the application should have a chance to see if it recognizes
it as a compressed or encrypted stream and would be able to wrap the input stream from URL resolution with a decompression/decryption wrapper before trying encoding detection again.  In my reading,
this would fall under the "wrapper of some kind" described in the encoding detection section of the XML recommendation.

When you know that a document is compressed or encrypted and does not have any external resources, then it you could pass a stream wrapped with decompression/decryption wrapper.  However, when you are
dealing with a document that might have compressed or encrypted external entities, DTDs, schemas, XInclude's, XLink's, etc, then that approach is insufficient.  There has been some discussion that you
might be able to use either the entity resolution mechanism or use a platform mechanism to address it, but I'm not convinced that those are sufficient.  If so, then the requirement would be a gimmee.

This requirement will probably come up for a vote (where only committer's votes are binding) in the next week or so.  There have been a couple of people who have expressed that they want the
requirement to be rejected.