Overview#The LDAP Pre-Read Control is a type of supportedControl that may be attached to an LDAP Delete Request, Modify Request, or ModifyDNRequest 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 220.127.116.11.1.13.1, and the value should be encoded in the same way as the AttributeSelection in a SearchRequest. The response control has an OID of 18.104.22.168.1.13.1 (the same as the OID for the request control), and the value should be encoded in the same was as a SearchResultEntry.
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=example,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