Just a few quick notes:
Apache2 ships DAV as a core module. Get the Apache2 tarball and look in modules/dav. I believe it is compiled in by default. The Apache2 crew is very bullish on DAV.
The Apache2 internals look very different from AOLserver, but they are not that different in practice. Much of the difference is cosmetic, and much more is simply things missing - for instance, there is no (yet) DB connection pooling API in Apache2. There are some scary things in terms of data structures (Apache2 uses some pool & table structs I haven't quite approved of yet), allocation methods (Apache2's approach to controlling memory leaks is a pool allocation scheme, so when the webserver wants to clean up a thread, it just nukes the pool; reminiscent of process clean-up), and there are some options not available in AOLserver, mostly more places in the request cycle to funge with things, and the ability to filter inputs & outputs from each and every module. Despite all that, I do not think it wise to re-implement everything. It is not, in any sense, a representative sample, but when I moved mod_scheme to ns_scheme, I think I changed 10 lines of code. I should however note that 1) I wrote the original code, and 2) I wrote it to be portable; but it *is* possible.
Certain parties have been goading me into working on an ns_dav built from mod_dav components. I'll add more later today when I have the time.
