[turba] Shared addressbook

[Kevin M. Myer]

Here's an attempt to summarize the different share options available in 
Turba. Some confusion likely arises from the use of the word "share", 
since it can
mean an object (Horde_Share) that permissions can be set on, and it can 
also be
a state that defines whether or not a preconfigured source is accessible by
more than one individual (i.e. the address book is shared).

In FRAMEWORK_3 code (Turba 2.X):
Check the 'public' and 'readonly' config options available for each 
source.  You
could create a read-only but public LDAP address book, which would serve as a
global shared address book, and also have a local private SQL addressbook.  Or
you could have a local private SQL address book (turba_objects table) and a
second SQL address book (turba_objects2 table, just clone the table name and
adjust the config accordingly, and set it to public).  And so on...

In HEAD code:
The above could still apply, although the config options have changed a 
bit.  A
new feature has been added that implements the Horde_Share concept.  It is
currently only supported for SQL address books, and I believe is largely
untested.  In answer to the question of why Turba didn't have this 
before? Likely because Turba was written before the concept of a Horde 
Share existed
and a wholesale replacement of the previous methods of sharing address books
would have broken backwards compatibility.  I'd guess you'd see a Share based
approach going forward and I'm sure testing and patches would be welcome and
would help that code advance more quickly.

Kevin

-- 
Kevin M. Myer
Senior Systems Administrator
Lancaster-Lebanon Intermediate Unit 13  http://www.iu13.org