The meaning of life and death

In a discussion taking place on the DASL list, it's become somewhat unclear
to me how to interpret section 3.1, which says "A live property has its
syntax and semantics enforced by the server".  I don't have a clear sense
of what is meant by "enforce", and hence what it means to have a life.  If
someone could answer the questions below it would help those of use
designing DASL.

1. What is life?

Suppose a property is stored (on the server) in an SQL table in a column
whose datatype is integer.  When the server does the PROPPATCH, it parses
the string to get the integer.  Does this parsing (regardless of how errors
are handled) suffice to make the property live?  Even if errors are
silently ignored?

Suppose a property is stored (on the server) as a compound data structure,
and expressed (on the wire) in XML as a set of marked up elements.  If the
server parses the XML to generate the data structure, is this a live property?

If not, suppose further that the datastructure has some optional elements,
with default values.  If the server provides these when creating the
datastructure, is it now live?

2. What is enforcement?
 
Clearly, rejecting a PROPPATCH with 409 Conflict is one form of enforcement. 
But is this the only kind of enforcement?

Suppose, in the examples above, the server is designed so that if the
parsing fails for any reason (e.g., the integer is malformed, or the XML
encoding is well-formed but not valid) it does not reject the PROPPATCH,
but instead simply neglects to change the value, or stores an XML element
indicating the failure. Is such behavior violation of the specification, or
does it simply consitute enforcement (albeit perhaps a poorly designed
one), and hence make the property live?

I don't see anyplace in the spec that says that the value returned by a
PROPFIND must be byte for byte identical with that deposited by PROPPATCH.
Even aside from access control, servers are surely allowed to do Unicode
canonicalization.  Or is this also an example of "enforcing" semantics?

best regards

Jim






------------------------------------
http://www.parc.xerox.com/jdavis/
650-812-4301

Received on Wednesday, 22 July 1998 01:01:04 UTC