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PHP : Function Reference : LDAP Functions : ldap_modify


Modify an LDAP entry (PHP 4, PHP 5)
bool ldap_modify ( resource link_identifier, string dn, array entry )

Code Examples / Notes » ldap_modify


To pinpoint the delete issue:
with newer OpenLdap versions this will fail:
$values["mail"] = "";
ldap_modify($conn_id, $dn, $values);
$values["mail"][0] = "";
ldap_modify($conn_id, $dn, $values);
BUT this works:
$values["mail"] = array();
ldap_modify($conn_id, $dn, $values);
$values["mail"][0] = array();
ldap_modify($conn_id, $dn, $values);


To delete entries:
$data["description"] = array();
ldap_modify($conn, $dn,$data);


The behaviour of OpenLDAP from 1.x to 2.x changed; in 1.x, when you passed ldap_modify the array, if the value was empty that attribute would be deleted.  In 2.x, you get an "Invalid Syntax" error and the modify fails.
This requires the ldap_mod_del function; unfortunately, that operation requires the attribute to be deleted have it's *old* value specified -- as you can imagine, if you're taking input from a CGI form, the attribute to be deleted's value is now missing (i.e., the user blanked out that textbox in the form and clicked Submit).
So, you're in a bit of a conundrum -- you want to delete "empty" form values, but you need their old value to delete them.  There are many ways to handle this, but I chose this approach:
// The first is what to add, the second to remove
// Imagine if you will, $o and $title are
// form fields with text boxes for data
if($o!="") { $entry["o"]="$o"; } else { $delval[]="o"; }
if($title!="") { $entry["title"]="$title"; } else { $delval[]="title"; }
// First try the normal modify with $entry
// $ldap, $dn, $BASEDN are all set up earlier
if (@ldap_modify($ldap, $dn, $entry)) {
 // then do the dirty work
 $filter = sprintf("(&(uid=%s)(sn=%s))",$uid,$sn);
 $sres = ldap_search($ldap, $BASEDN, $filter, $delval);
 $delent = ldap_first_entry($ldap, $sres);
 $delarr = ldap_get_attributes($ldap, $delent);
 for($i=0; $i<$delarr["count"]; $i++) {
   $attr = $delarr[$i];
   $totl = $delarr[$attr]["count"];
   for($z=0; $z<$totl; $z++) {
     if ($totl = 1) {
     } else {
 if(@ldap_mod_del($ldap, $dn, $findel)) {
   print("<H3>Modified Entry!</H3>\n");
 } else {
   print("<H3>Attribute Delete Failed!</H3>\n");
} else {
 print("<H3>Modify Failed!</H3>\n");


The $entry parameter can be an array of values for an attribute. Just be careful that your array's indices are numerically contiguous. For example, when using this $entry array, ldap_modify will fail with little explanation:
  $entry = array( 0 => 'foo', 2 => 'bar' );
While this one will work just fine:
  $entry = array( 0 => 'foo', 1 => 'bar' );
Hope this helps someone out.


Some comments on ldap_modify, and especially the user comment from tengel at fluid dot com
OpenLDAP 2.1.22
If an attribute is tagged as MUST in the schema, the attribute must be there. Wheter it may contain and empty value depends on the SYNTAX for that attribute.
DirectoryString MAY NOT be empty; OctetString MAY be empty. As far as I can see, IA5String MAY NOT be empty.
If an attribute is defined as MAY in the schema, the attribute may or may not be there. If it is there, it MAY or MAY NOT be empty, depending on its SYNTAX.
PHP 4.3.1
It seems that ldap_modify() will take an array of attributes to modify.
For multivalued attributes, passing an empty array, wil DELETE the attribute, regardless of it's previous value(s), and regardless if the attribute was there before the modify.
If the multivalued attribute is defined as MAY, this will work. If the attribute is defined as MUST, OpenLDAP will generate the error: 'LDAP error 65: Object class violation'
If an attribute's SYNTAX defines that it MAY NOT be empty, trying to add or modify the attribute with an empty value will genereate the error: 'LDAP error 21: Invalid syntax'.
Also, in the logfile, if set with sufficient debuglevel, the string
value #0 invalid per syntax
will be present.
Trying to pass an empty array to ldap_add() for a any attribute (multi or single valued) will result in the error 'LDAP error 2: Protocol error', regardless if the attribute is defined as MUST or MAY.
Note that this differs form passing an array with elements that have no value. In the latter case, it depends on the SYNTAX for that attribute if that is allowed.
If the attribute is single-valued, passing an array with one element, WILL change the value of the attribute. In the user comments on it is suggested that if you want to modify a single valued attribute, you must pass a string, not an array with one element. My experience is that an array with a single element will work just as well.
website: *


Remember that you can NOT modify the attribute 'objectclass' with ldap_modify!
If you use a search result as basis for your changes, be sure to 'unset()' all numbered indices, 'count' indicies AND index 'objectclass' !


Nick T.'s comment above is out of date.
The PHP LDAP interface currently supports direct modification of the DN using the ldap_rename() function.


Modifying existing LDAP information using ldap_modify()
The link_identifier must result from a call to connect to the server with authority to update entries, usually requiring an authenticated bind - ie you provide a suitable dn and password in the ldap_bind() call.

The  dn  must be a single specific dn that exists on the LDAP server.   There is no wildcard mechanism in LDAP to globally change multiple dn entries.  

The entry array must be in one of two different forms, according to whether just one entry is to be stored in the directory for a particular attribute, or whether multiple entries are to be stored for the attribute.

Where a single entry is to be stored for an attribute - say just a single email address - then you use the general form
            $newinfo[ <attribute_name> ]="whatever" ;
for example ...
            $newinfo["mail"]="" ;
Where multiple entries are to be stored for an attribute  -  say a number of email addresses for one person  -  then you use the general form
            $newinfo[ <attribute_name> ][0] = "whatever" ;
            $newinfo[ <attribute_name> ][1] = "another" ;
for example ...
            $newinfo["mail"][0]="" ;
            $newinfo["mail"][1]="" ;
Further notes on ldap_modify()
The modify call leaves entries for all other attributes unaltered.   So if you just want to update the entry for the "mail" attribute, then all that is required is:
    ldap_modify($valid_ldaplink, $valid_dn, $newinfo);
However, if there were multiple entries for the mail attribute present on the LDAP database when you run the above code, then all the existing mail entries would be deleted and be replaced by the single "mail" entry.

If you have reason to expect multiple values for a particular attribute (more that one email entry, for example) you should make sure you read all the entries from the ldap server first, and then save a modified array.

The PHP LDAP interface does not currently support direct modification of the dn.  If the dn needs changing, the only option is to read all entries for the dn and save these to a new, modified, dn before deleting the complete entry for the original dn.


If you're writing a multiple values for an attribute with ldap_modify (), the function will attempt to write all entries in the value array even if those entries are blank.  Setting blank entries to a blank array in the manner used for attribute deletion, ie:
$attributes[$attr_name][3] = array ();
results in the string "Array" being written to the directory for that value.  The only way I was able to find to do what I wanted - only write the values for the attribute that were submitted on the form - was to check if each attribute had multiple values and unset () blank values, eg:
               foreach ($attributes as $key => $cur_val) {
                       if ($cur_val== '') {
                               $attributes[$key] = array ();
                       if (is_array ($cur_val)) {
                               foreach ($cur_val as $mv_key => $mv_cur_val) {
                                       if ($mv_cur_val == '') {
                                               unset ($attributes[$key][$mv_key]);
                                       else {
                                               $attributes[$key][$mv_key] = $mv_cur_val;                      


If you're seeing confusing "Type or value exists" errors from ldap_modify, the reason could be that you're attempting to add two identical values for a multi-valued attribute.  ie, something like:
$le = array("mail" => array("", ""));
$result = ldap_modify($ldap_link, $dn, $le);


If you want to disable an account in an Active Directory of Windows,
you may try this (it works for me in a Win2k environment):
( should be replaced in "$ldapBase" to the correct
domain, e.g. "DC=phpfreackx,DC=com" if your domain is
domctrl = domain controller
domadlogin = domain admin login
domadpw = domain admin password
username = loginname of useraccount (e.g. "john.doe")
enable =1 (if you want to enable it, 0 if it should be disabled)
function userchange($username,$enable=1,$domadlogin,$domadpw,$domctrl)
$ldapServer = $domctrl;
$ldapBase = 'DC=foo,DC=bar';
$ds = ldap_connect($ldapServer);
if (!$ds) {die('Cannot Connect to LDAP server');}
$ldapBind = ldap_bind($ds,$domadlogin,$domadpw);
if (!$ldapBind) {die('Cannot Bind to LDAP server');}
ldap_set_option($ds, LDAP_OPT_PROTOCOL_VERSION, 3);
$sr = ldap_search($ds, $ldapBase, "(samaccountname=$username)");
$ent= ldap_get_entries($ds,$sr);
// Deactivate
$ac = $ent[0]["useraccountcontrol"][0];
$disable=($ac |  2); // set all bits plus bit 1 (=dec2)
$enable =($ac & ~2); // set all bits minus bit 1 (=dec2)
if ($enable==1) $new=$enable; else $new=$disable; //enable or disable?
ldap_modify($ds, $dn, $userdata); //change state
$sr = ldap_search($ds, $ldapBase, "(samaccountname=$username)");
$ent= ldap_get_entries($ds,$sr);
$ac = $ent[0]["useraccountcontrol"][0];
if (($ac & 2)==2) $status=0; else $status=1;
return $status; //return current status (1=enabled, 0=disabled)
// use this to disable an account:
// userchange('',0,'', 'secret','');
// ..but this to enable it:
// userchange('',1,'', 'secret','');


If you are trying to change the userPassword attribute when using md5 hashes, try the following lines:
$new["userPassword"] = '{md5}' . base64_encode(pack('H*', md5($newpass_in_plaintext)));
ldap_modify($ds, $dn, $new);


Following goetz at rvs dot uni-hannover dot de's comment, it is not exactly true that ldap_modify can't change objectclass.
In fact, it's impossible to add an objectclass which is set as STRUCTURAL in the schema description. But you can add an objectclass set as AUXILIARY. See OpenLDAP FAQ below for explanation why :
For example, if you have an ldap entry of type "device", which is a structural objectclass, named "cn=myNetCard,ou=Networks,dc=example,dc=com", you can do this :
$entry["objectclass"][0] = "device";
$entry["objectclass"][1] = "ieee802Device"; // add an auxiliary objectclass
$entry["macAddress"][0] = "aa:bb:cc:dd:ee:ff";
ldap_modify ($cnx, "cn=myNetCard,ou=Networks,dc=example,dc=com", $entry);
But this will not work :
$entry["objectclass"][0] = "device";
$entry["objectclass"][1] = "ipNetwork"; // add a structural objectclass
$entry["ipNetworkNumber"][0] = "";
ldap_modify ($cnx, "cn=myNetCard,ou=Networks,dc=example,dc=com", $entry);
You will get the following error : "Cannot modify object class"

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