LDAP pre-read control

The LDAP pre-read control is a type of control that may be attached to an LDAP delete operation, modify operation, or modify DN operation operation to request that the server return a copy of the target entry exactly as it was immediately before the processing for that operation. It is one of the LDAP read entry controls defined in RFC 4527.

The pre-read request control has an OID of 1.3.6.1.1.13.1, and the value should be encoded in the same way as the search attributes in a search operation. The response control has an OID of 1.3.6.1.1.13.1 (the same as the OID for the request control), and the value should be encoded in the same was as a search result entry.

The following example shows the use of the pre-read control in an ldapmodify request:

$ ldapmodify -h localhost -p 1389 -D "cn=directory manager" -w password \
--preReadAttributes=telephoneNumber
dn: uid=aaltay,ou=People,dc=example,dc=com
changetype: modify
replace: telephoneNumber
telephoneNumber: +1 995 589 4444

Processing MODIFY request for uid=user.199,ou=People,dc=exampele,dc=com
MODIFY operation successful for DN uid=aaltay,ou=People,dc=example,dc=com 
Target entry before the operation:
dn: uid=aaltay.199,ou=People,dc=example,dc=com 
telephoneNumber: +1 995 589 3333