- From: <noah_mendelsohn@us.ibm.com>
- Date: Tue, 18 May 2004 22:45:23 -0400
- To: xml-dist-app@w3.org
With apologies for not having gotten to it until the last minute, I've done a readthrough of the XOP draft. I understand that there may not be time to consider the following prior to last call, but I think at least some of these might merit attention. They're sorted roughly into most important, less important, and editorial. I haven't gotten to MTOM yet, and I'm at www2004. I will try to find some time before tomorrow's call to read and enter comments on that, but it looks unlikely I'll manage it. Maybe someone else can find the time to doublecheck it? Most Important -------------- * Section 1. The intro currently says: "When XOP is used as intended, binary data will never be encoded in base64 form. Indeed, to add binary data into an XML Document, a XOP-aware application will add the linking element at the correct location in the XML and place the binary data directly into the package. " That seems too strong, as we do intend that the characters be made available in a variety of situations including dsig, re-encoding into XML 1.0, etc. Furthermore, I strongly object to the suggestion that applications directly create xop:include elements, as this is quite likely to be done by middleware. How about: "In a number of important XOP applications, binary data need never be encoded in base64 form. If the data to be included is already available as a binary octet stream, then either an application or other software acting on its behalf can directly copy that data into a XOP package, at the same time preparing suitable linking elements for use in the root part; when parsing a XOP package the binary data can be made available directly to applications, or if appropriate, the base64Binary character representation can be computed from the binary." * Section 3: Suggest changing "An informative XML Schema" to "A non-normative XML schema". I hope it's informative either way, but the point is that it is not normative. Any reason not to just say that? * Section 3.2: see emails from me and from Gudge suggesting that we reference Schema datatypes anyURI for the lexical form of the content of the href attribute. I'm offline and don't have the archive link, but mine was sent on Tues 5/18. Less Important -------------- * Section 1. The introduction doesn't mention xop-mime:content-type. This seems to be a significant function, since it is for use in user content as opposed to just in the xop internals. Should we not set it up with a sentence or two of introduction? Perhaps something like: "This specification also introduces an attribute xop-mime:content-type which may be used in XML documents to indicate the media type of base64Binary content. XOP uses this attribute, if present, to provide suitable typing for MIME multipart/related parts." * Section 1.1 Note: "Mark proposes to change "any W3C recommendation-level version of XML" to "XML". The current text comes from the resolution of rec20 and rec22. Do we want to change it? " I'm inclined to keep it as is. I'm not sure that "XML" unqualified is sufficiently unambiguous. I'm not arguing that it's actually wrong, but I think we will get questions from users asking: can I use XML 1.1? Why not provide an answer in advance? See also item 1 in the instructions for reconstituting in section 4.2, which makes the connection from XML declarations to levels of the XML Recommendation. * Section 2: "The subsection below specifies how a particular packaging mechanism, MIME Multipart/Related, is used, but does not preclude the use of other packaging mechanisms with the XOP convention." I suggest adding the word normative as follows: "The subsection below specifies >normatively< how a particular packaging mechanism, MIME Multipart/Related, is used, but does not preclude the use of other packaging mechanisms with the XOP convention. " Reason: without this, it all seems sort of vague. You can do whatever you like. With this, it makes clear that there is a normative multipart representation with conformance requirements specified in the rec. Indeed, you can also use XOP as a framework for inventing your own, but the rules for building a multipart are normative when that's what you decide to do. * Section 5: "Note that there is currently no convention for structuring XOP-based media types." -> "Note that there is currently no convention for structuring >the names of< XOP-based media types. " Reason: this whole rec IS about conventions for structuring XOP media types. * Section 6: "The integrity of XOP Packages may need to be ensured. As such packages can be transformed to an XML Information Set, existing XML Digital Signature techniques can be used to protect such packages. " -> "The integrity of >Infosets optimized using XOP< may need to be ensured. As XOP packages can be transformed to recover such Infosets (see section 4.2), existing XML Digital Signature techniques can be used to protect such them. Note, however, that a signature over the Infoset does not necessarily protect against modifications of other aspects of the XOP packaging; for example, an Infoset signature check might not protect against an exchange of position of two non-root parts. To protect against such modifications, the serialization of the multipart related or other package would have to be signed, but no standard means is here proposed for computing package-level signatures." Reason: should be self-explanatory. DSigs over the infoset DO NOT protect the package, and one can imagine situations in which protection of the package is needed. In any case, we should be careful in making such claims. Editorial or minor ------------------ * Section 1. "In the reverse direction, XOP only allows to extract from an XML Infoset base64-encoded data that is in the canonical lexical form. " -> "In the reverse direction, XOP is capable of optimizing only base64-encoded Infoset data that is in canonical lexical form." * Section 3. "Infoset containing such element information item cannot be serialized using XOP. " -> ">Infosets< containing such element information >items< cannot be serialized using XOP. " * Section 3.1. "There MAY be zero or more namespace qualified element information items in its [children] property. Any such element information item MUST have a [namespace name] different of "http://www.w3.org/2003/12/xop/include". " I suggest: "There MAY be zero or more namespace qualified element information items in its [children] property. Any such element information item MUST have a [namespace name] and that name MUST NOT be "http://www.w3.org/2003/12/xop/include". " * Section 3.1: Suggest: "Any other namespace qualified attribute information items with a [namespace name] different of "http://www.w3.org/2003/12/xop/include". " -> "Other attribute information items; these MUST have a [namespace name] the value of which MUST NOT be "http://www.w3.org/2003/12/xop/include"." * Section 5: "To enable applications to identify the use of XOP as well as the original Infoset's media type, formats wishing to allow XOP serialization MUST register a distinct media type that identifies the format of the XOP Infoset." I think it's a bit clumsy to imply that formats can wish for things. How about: "To enable applications to identify the use of XOP as well as the original Infoset's media type, a distinct media type MUST be registered for each application of XOP to a particular XML application vocabulary." * Section 5: "For example, if the format identified by "application/soap+xml" wishes to enable applications to identify XOP serializations, it MUST register a XOP-specific media type (e.g., "application/soap_xop+xml")." for the same reason I suggest "For example, if the format identified by "application/soap+xml" is to be packaged as XOP serializations, then a XOP-specific media type (e.g., "application/soap_xop+xml") MUST be registered. " Notwithstanding the above comments, I think the recent draft is overall really good. Thanks to Herve and Mark, who I believe are responsible for most of the hard work on this. -------------------------------------- Noah Mendelsohn IBM Corporation One Rogers Street Cambridge, MA 02142 1-617-693-4036 --------------------------------------
Received on Tuesday, 18 May 2004 22:49:24 UTC