Read Entry Controls


Overview

Added support for RFC 4527 - Read Entry Controls in Directory Server 1.3.2. The Directory Server now supports the pre & post read entry response controls. If one of these response controls is requested by a client, an ldap search entry is returned that contains the pre/post changes to the entry. This entry only contains for the changes for the attribute that was listed in the control.

Use Cases

Now that 389 DS has converted most of its plug-ins that perform internal write operations to betxn plug-ins, we can return an entry that was modified by a plug-in with the post-read control. This is very useful when using plug-ins like DNA or memberOf.

ldapmodify example showing how the attribute description was modified:

ldapmodify -D "cn=directory manager" -w password  -e \!preread=description -e \!postread=description 
dn: cn=entry,dc=example,dc=com
changetype: modify
replace: description
description: new description

modifying entry "cn=entry,dc=example,dc=com"
control: 1.3.6.1.1.13.1 false MEIEHGNuPWV4YW1wbGUsZGM9ZXhhbXBsZSxkYz1jb20wIjAg
 BAtkZXNjcmlwdGlvbjERBA9uZXcgZGVzY3JpcHRpb24=
# ==> preread
dn: cn=entry,dc=example,dc=com
description: old description
# <== preread
control: 1.3.6.1.1.13.2 false MEkEHGNuPWV4YW1wbGUsZGM9ZXhhbXBsZSxkYz1jb20wKTAn
 BAtkZXNjcmlwdGlvbjEYBBZuZXcgZGVzY3JpcHRpb24gZm9yIFFF
# ==> postread
dn: cn=entry,dc=example,dc=com
description: new description
# <== postread

Design

pre-read entry control:  1.3.6.1.1.13.1
post-read entry control: 1.3.6.1.1.13.2

The pre-read control returns a copy of the entry before it was modifed, and the post-read control returns the entry after the modify. Both controls can be used for the same operation. The control is added just before the result is returned to the client.

Implementation

None.

Major configuration options and enablement

None.

Replication

None.

Updates and Upgrades

None.

Dependencies

Available on 1.3.2 and up.

External Impact

None.

Author

mreynolds@redhat.com

Last modified on 13 October 2014