The biggest item has to do with having to know the response code for the request without processing the request. Specifically, 14.24 (If-Match) and the others have a requirement like:
If the request would, without the If-Match header field, result in anything other than a 2xx status, then the If-Match header MUST be
ignored.
This implies that we have to attempt the request, check the
status, and act on the If-Match header only if the request resulted
in an non-error status. That seems rather expensive for the server.
For example, if we have a GET request that recomputes uncached data
or something like that.
Furthermore, for many operations, such as PUT, COPY, MOVE and DELETE, we'd have to back out the successful operation, since I might not know that PUT will fail without actually trying it first.
Next up, 14.25 (If-Modified-Since) implies in the first paragraph that it applies to all methods, but then only proceeds to describe what to do with a GET, and even then, a GET with no Range header. If I get an IMS for a PUT, is that a valid request? How about a DAV COPY? Presumably in that case would apply, if valid, to the source resource, not the destination.
-wsv
smime.p7s
Description: S/MIME cryptographic signature
