- From: <Noah_Mendelsohn@lotus.com>
- Date: Fri, 21 Sep 2001 10:57:44 -0400
- To: francis@redrice.com
- Cc: "Champion, Mike" <Mike.Champion@SoftwareAG-USA.com>, xml-dist-app@w3.org, xml-dist-app-request@w3.org
Francis Norton writes: >> Why do you exclude the payload? Are SOAP payloads >> allowed to contain DTDs and PIs? As I said in my previous note, having a way to allow a payload to carry an entire XML document would be a good thing. Bad news: XML itself doesn't allow it, one of the primary failings of XML IMO (a hierarchical format that can't contain itself.) Why? Well among other reasons, you can't have multiple internal subset DTD's in an XML document. There's no scoping mechanism for them. You might also want to switch encodings (e.g. a schema in UTF8 describing a document in BIG5, both in the same envelope.) General entities can't have conflicting names in the same document, etc., etc. So, a good goal, but if we don't revise XML itself we will have to either use encoding tricks, something like SOAP+attachments, etc. You cannot in general carry a complete XML document, or even just an extra payload-oriented internal subset DTD, within what is otherwise an XML SOAP envelope document. BTW: the statements about schema are true. It doesn't let you declare entities. As I said in my previous note, entities are useful, but they do have performance implications. I'm not convinced that for applications like web services messaging they are worth the cost. ------------------------------------------------------------------------ Noah Mendelsohn Voice: 1-617-693-4036 Lotus Development Corp. Fax: 1-617-693-8676 One Rogers Street Cambridge, MA 02142 ------------------------------------------------------------------------
Received on Friday, 21 September 2001 11:06:11 UTC