[DAS2] search by segment id

[Andrew Dalke]

One thing I came up with yesterday when moving from local identifiers
to URIs for the segment names.  There are two possible identifiers
for a given segment

<das:SEGMENTS xmlns:das="http://www.biodas.org/ns/das/genome/2.00"
        xml:base="http://localhost/das2/">
  <das:SEGMENT uri="segment/chr1" title="Chromosome 1" length="246127941"
    synonym="http://dalkescientific.com/human35v1/chr1"
    doc_href="http://www.ensembl.org/Homo_sapiens/mapview?chr=1" />


The local name is "http://localhost/das2/segment/chr1" while
the well-known global name (of which the local name is an alias) is
"http://dalkescientific.com/human35v1/chr1"

The global name can be anything.  It can be "urn:lsid:chr1" or
anything else.  It only needs to be unique across all identifiers.

Now, are range queries done with the local name or the global one?

That is,   
features?segment=http://localhost/das2/segment/chr1&range=100:200

      or  
features?segment=http://dalkescientific.com/human35v1/chr1&range=100: 
200
    ( or features?segment=urn:lsid:chr1&range=100:200 if that was the  
uri)


If it's the local name then the client must first query all servers
to get the mapping from global name to local name, and perform the
translation itself.

I propose that the client can query using the global name, and not
need to do the mapping to the local name.  In addition, a server
may support both names in the query, since by using URIs we guarantee
there are no accidental id collisions.

					Andrew
					dalke at dalkescientific.com