Version Control with Subversion

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Appendix C: WebDAV and Autoversioning

actually be quite difficult to implement, since Subversion uses the copy-modify-

merge model.

*

In Apache httpd-2.0, mod_dav supports the LOCK method by tracking locks in a pri-

vate database, assuming that the provider is willing to accept them. In Apache httpd-

2.1 or later, however, this locking support has been broken into an independent

module, mod_dav_lock. It allows any mod_dav provider to take advantage of the

lock database, including mod_dav_svn, even though mod_dav_svn doesn’t actually

understand locking.

Confused yet?

In a nutshell, you can use mod_dav_lock in Apache httpd-2.1 (or later) to create the

illusion that mod_dav_svn is honoring

LOCK requests. Make sure mod_dav_lock is

either compiled into httpd, or being loaded in your httpd.conf. Then simply add the

DAVGenericLockDB directive to your Location like so:

<Location /repos>

DAV svn

SVNPath /absolute/path/to/repository

SVNAutoversioning on

DavGenericLockDB /path/to/store/locks

</Location>

This technique is a risky business; in some sense, the mod_dav_svn is now lying to

the WebDAV client. It claims to accept the

LOCK request, but in reality the lock isn’t

being enforced at all levels. If a second WebDAV client attempts to

LOCK the same

resource, then mod_dav_lock will notice and correctly ...