Groups are useful for more than just populating the user’s
LDAPBackend would not be complete without
some way to turn a user’s LDAP group memberships into Django model permissions.
In fact, there are two ways to do this.
Ultimately, both mechanisms need some way to map LDAP groups to Django groups.
LDAPGroupType will have an
algorithm for deriving the Django group name from the LDAP group. Clients that
need to modify this behavior can subclass the
LDAPGroupType class. All of the built-in
implementations take a
name_attr argument to
specifies the LDAP attribute from which to take the Django group name. By
cn attribute is used.
Using Groups Directly¶
The least invasive way to map group permissions is to set
LDAPBackend will then find all of the LDAP
groups that a user belongs to, map them to Django groups, and load the
permissions for those groups. You will need to create the Django groups and
associate permissions yourself, generally through the admin interface.
To minimize traffic to the LDAP server,
LDAPBackend can make use of Django’s cache
framework to keep a copy of a user’s LDAP group memberships. To enable this
AUTH_LDAP_CACHE_TIMEOUT, which determines the timeout
of cache entries in seconds.
AUTH_LDAP_CACHE_TIMEOUT = 3600
The second way to turn LDAP group memberships into permissions is to mirror the groups themselves. This approach has some important disadvantages and should be avoided if possible. For one thing, membership will only be updated when the user authenticates, which may be especially inappropriate for sites with long session timeouts.
True, then every time a user logs
LDAPBackend will update the database with
the user’s LDAP groups. Any group that doesn’t exist will be created and the
user’s Django group membership will be updated to exactly match their LDAP group
membership. If the LDAP server has nested groups, the Django database will end
up with a flattened representation. For group mirroring to have any effect, you
of course need
ModelBackend installed as
an authentication backend.
By default, we assume that LDAP is the sole authority on group membership; if
you remove a user from a group in LDAP, they will be removed from the
corresponding Django group the next time they log in. It is also possible to
have django-auth-ldap ignore some Django groups, presumably because they are
managed manually or through some other mechanism. If
AUTH_LDAP_MIRROR_GROUPS is a list of group names, we will manage
these groups and no others. If
AUTH_LDAP_MIRROR_GROUPS_EXCEPT is a
list of group names, we will manage all groups except those named;
AUTH_LDAP_MIRROR_GROUPS is ignored in this case.
LDAPBackend has one more feature pertaining
to permissions, which is the ability to handle authorization for users that it
did not authenticate. For example, you might be using
to map externally authenticated users to Django users. By setting
LDAPBackend will map these users to LDAP
users in the normal way in order to provide authorization information. Note that
this does not work with
AUTH_LDAP_MIRROR_GROUPS; group mirroring is
a feature of authentication, not authorization.