[DAS2] more small changes

[Andrew Dalke]

Here's some more small changes I would like to make upon
reviewing the spec some more.  These are all pushing for
consistency of the Content-Type and DTD names.  As I
expect it isn't a problem I'll go ahead and make the
changes, subject to reversal in the future if so decided.

 > Fetching Information about Data Sources: The Sources Request
 >
 > Performing a GET on the DAS base URL is known as a "sources"
 > request, ... of type text/x-das-source+xml, and a compact
 > tab-delimited format of type text/x-das-source+compact.
   ...
 >   <?xml version="1.0" standalone="no"?>
 >   <!DOCTYPE DAS2DSN SYSTEM "http://www.biodas.org/dtd/das2dsn.dtd">

It's called "sources" so I think the content types should be
"text/x-das-sources+xml" and "text/x-das-sources+compact" instead
of the singular "source".

I also think the DOCTYPE line should be

  <!DOCTYPE SOURCES SYSTEM "http://www.biodas.org/dtd/das2sources.dtd">

in part because I don't know what "dsn" means.  DAS Source something?


 > Fetching Information About a Versioned Source: The Versioned
 >   Source Request
 >
 > By adding the version to the end of the path, the URL becomes an 
identifier
 > for the versioned data source. Retrieving it returns a document that
 > provides metadata about the data source and the capabilities that the
 > DAS/2 server provides for manipulating the data source.
 >
 > REQUEST:
 > http://www.wormbase.org/das/genome/volvox/2
 >
 > RESPONSE:
 > Content-Type: text/x-das-source-details+xml

The word "details" does not exist in the description.  The word
"version" does, in several forms.  I propose using the

Content-Type: text/x-das-source-version+xml

Similarly I propose changing
<!DOCTYPE DAS2DSNDETAILS SYSTEM 
"http://www.biodas.org/dtd/das2dsndetails.dtd">
  to use
<!DOCTYPE SOURCE SYSTEM 
"http://www.biodas.org/dtd/das2sourceversion.dtd">

Sadly that's a very long name.  I could go with "das2version".


 > Fetching Information About Feature Types: The "Types" Request
  ...
 > Content-Type: text/x-das-featuretype+xml
  ...
 > Content-Type: text/x-das-featuretype+compact

In here I suggest using
   Content-Type: text/x-das-types+xml
   Content-Type: text/x-das-types+compact

The DOCTYPE DTD URL is fine.


 > Fetching Information About Features: The Feature Request

I haven't figured out the rule for when something is a
singular request vs. when it's a plural request.  Earlier
it was a "Types" request when "type/" is appended to a
versioned data source URL.  It seems that this should be
a "Features" request.

 > The Das2XML-Formatted Feature Response
  ...
 > Content-Type: text/x-das-feature+xml
  ...
 > <!DOCTYPE DAS2FEATURE SYSTEM 
"http://www.biodas.org/dtd/das2feature.dtd">

This returns a list of features so should be "features"

  Content-Type: text/x-das-features+xml
  <!DOCTYPE FEATURES SYSTEM "http://www.biodas.org/dtd/das2features.dtd">

 > Retrieving Regions & Assemblies

by homology this should be
  Retrieving Regions & Assemblies: the "Regions" request

 >  Content-Type: text/x-das-region+xml
 >  <!DOCTYPE DAS2REGIONS SYSTEM 
"http://www.biodas.org/dtd/das2regions.dtd">

and those should be
   Content-Type: text/x-das-regions+xml
   <!DOCTYPE REGIONS SYSTEM "http://www.biodas.org/dtd/das2regions.dtd">

 > Retrieving Controlled Vocabularies of Property Types
  ...
 > Content-Type: text/x-das-property+xml
  ...
 >  <!DOCTYPE DAS2PROPERTIES SYSTEM 
"http://www.biodas.org/dtd/das2properties.dtd">

By now you all have probably gotten the hang of things ;)

  Content-Type: text/x-das-properties+xml
  <!DOCTYPE PROPERTIES SYSTEM 
"http://www.biodas.org/dtd/das2properties.dtd">


One last point. The sources request is one request that can
return a list of 0 or more <SOURCE> elements.  It is described
with a schema that allows zeroOrMore SOURCE elements.

A source request (for a single source and not a list of sources)
returns an XML document that is described with the same schema.
It looks like
   <SOURCES>
    <SOOURCE>
      <!-- there is one and only one SOURCE in this list -->
    </SOURCE>
   </SOURCES>

In use there will only be one SOURCE in the SOURCES so a
more precise schema could enforce that.

Personally I'm okay with it is as it is.  That makes for
about 3 fewer schemas and the expense of one extra check
in the client.  I'm just pointing it out.  'Cause that's
the way I am.  :)

					Andrew
					dalke at dalkescientific.com