Every HTTP library I have ever used parses HTTP headers and puts them in a nice hash for you ready to consume. If we go for "Name: Value" then that's all there is to it. If we go for "Attribute: name=value" as is currently proposed (which is arguably cleaner, follows cookies' "prior art" and avoids Amazon's prefix hack) then you just have to split on '='.
To illustrate how clean this is by example:
#!/usr/bin/python
import urllib2
response = urllib2.urlopen('http://cloud.example.com/myvm')
representation = response.read()
metadata = response.info()
print metadata['occi-compute-cores']
As soon as you start talking about payloads you have to fire up a parser (JSON/XML/Atom/etc.) or write your own (previous text rendering) which is
significantly more work to do at both design and run times. Not to mention more work for us to do now and more scope for interoperability problems.
Sam