[DAS2] starting the validation work

[Andrew Dalke]

Hi all,

  I've started to work on the validation.  I'm going through
the HTML spec in CVS.  Fixed a couple of small typos already.

Here's things I haven't been able to resolve so far.

The sources request document starts like this (I changed
it to a local DTD for testing)

<?xml version="1.0" standalone="no"?>
<!DOCTYPE DAS2DSN SYSTEM "das-source.dtd">
<SOURCES>

According to http://www.w3.org/TR/REC-xml/

     Validity constraint: Root Element Type

     The Name in the document type declaration MUST match the
     element type of the root element.

I think that means the doctype should be

<!DOCTYPE SOURCES SYSTEM "das-source.dtd">
           ^^^^^^^--- this changed

It looks like we could also do

<!DOCTYPE SOURCES PUBLIC "-//OBF DAS2 DSN//DTD/EN"
                    "http://www.biodas.org/das2dsn.dtd">

which would let an XML reader check if it knows the
public name and if not fetch it from the given URL.

If I follow it correctly we could just have a single
DTD URL for everything we return because the first
term in the doctype specifies the start element in
the DTD.  Something like

<!DOCTYPE SOURCES PUBLIC "-//OBF DAS2 DSN//DTD/EN"
                    "http://www.biodas.org/das2.dtd">

<!DOCTYPE SOURCE PUBLIC "-//OBF DAS2 DSN//DTD/EN"
                    "http://www.biodas.org/das2.dtd">

<!DOCTYPE TYPES PUBLIC "-//OBF DAS2 DSN//DTD/EN"
                    "http://www.biodas.org/das2.dtd">


Second, in reading through things it looks like the
general decision in the XML community is to use the
phrase "URI" instead of "URN".  Eg, see the XML schema
document at http://www.w3.org/TR/xmlschema-2/#anyURI
where it uses URI and not URN.  Indeed RFC 2396 says

http://www.ietf.org/rfc/rfc2396.txt
    A URI can be further classified as a locator, a name, or both.  The
    term "Uniform Resource Locator" (URL) refers to the subset of URI
    that identify resources via a representation of their primary access
    mechanism (e.g., their network "location"), rather than identifying
    the resource by name or by some other attribute(s) of that resource.
    The term "Uniform Resource Name" (URN) refers to the subset of URI
    that are required to remain globally unique and persistent even when
    the resource ceases to exist or becomes unavailable.

This is different than what we use in the DAS2 spec,
which says things like

   The id attribute is a  URN (typically in the form of a relative URL)

Shall I go through and change the "URN"s to "URI"s in the docs?


					Andrew
					dalke at dalkescientific.com