ldap_read()

(PHP 4, PHP 5, PHP 7)

Read an entry

说明

ldap_read(resource $link_identifier,string $base_dn,string $filter[,array $attributes= array("*")[,int $attrsonly= 0[,int $sizelimit= -1[,int $timelimit= -1[,int $deref= LDAP_DEREF_NEVER[,array $serverctrls= array()]]]]]]): resource

Performs the search for a specified$filteron the directory with the scope LDAP_SCOPE_BASE. So it is equivalent to reading an entry from the directory.

参数

$link_identifier

An LDAP link identifier, returned by ldap_connect().

$base_dn

The base DN for the directory.

$filter

An empty filter is not allowed. If you want to retrieve absolutely all information for this entry, use a filter ofobjectClass=*. If you know which entry types are used on the directory server, you might use an appropriate filter such asobjectClass=inetOrgPerson.

$attributes

An array of the required attributes, e.g. array("mail","sn","cn"). Note that the "dn" is always returned irrespective of which attributes types are requested.

Using this parameter is much more efficient than the default action(which is to return all attributes and their associated values). The use of this parameter should therefore be considered good practice.

$attrsonly

Should be set to 1 if only attribute types are wanted. If set to 0 both attributes types and attribute values are fetched which is the default behaviour.

$sizelimit

Enables you to limit the count of entries fetched. Setting this to 0 means no limit.

Note:

This parameter can NOT override server-side preset sizelimit. You can set it lower though.

Some directory server hosts will be configured to return no more than a preset number of entries. If this occurs, the server will indicate that it has only returned a partial results set. This also occurs if you use this parameter to limit the count of fetched entries.

$timelimit

Sets the number of seconds how long is spend on the search. Setting this to 0 means no limit.

Note:

This parameter can NOT override server-side preset timelimit. You can set it lower though.

$deref

Specifies how aliases should be handled during the search. It can be one of the following:

• LDAP_DEREF_NEVER-(default)aliases are never dereferenced.
• LDAP_DEREF_SEARCHING- aliases should be dereferenced during the search but not when locating the base object of the search.
• LDAP_DEREF_FINDING- aliases should be dereferenced when locating the base object but not during the search.
• LDAP_DEREF_ALWAYS- aliases should be dereferenced always.

$serverctrls

Array of LDAP Controls to send with the request.

返回值

Returns a search result identifier or FALSE on error.

更新日志

Clarification of the ldap_read command syntax: 
If you just want to pull certain attributes from an object and you already know it's dn, the ldap_read command can do this as illustrated below. It will be less overhead than ldap_search.
The string base_dn which is normally used to set the top context for a recursive ldap_search is used slightly differently with this command. It is used to specify the actual object with the full dn. (Hopefully this saves someone else a couple hours trying this command out.)
<?php
$ds = ldap.myserver.com // your ldap server
 $dn = "cn=username,o=My Company, c=US"; //the object itself instead of the top search level as in ldap_search
 $filter="(objectclass=*)"; // this command requires some filter
 $justthese = array("ou", "sn", "givenname", "mail"); //the attributes to pull, which is much more efficient than pulling all attributes if you don't do this
   $sr=ldap_read($ds, $dn, $filter, $justthese);
     $entry = ldap_get_entries($ds, $sr);
echo $entry[0]["mail"][0] . "is the email address of the cn your requested";
echo $entry[0]["sn"][0] . "is the sn of the cn your requested";
ldap_close($ds);
?> 
This prints out the specified users mail and surname for example.

The array in the attributes parameter needs to be an indexed array with numeric keys in ascending order. Like this:
Array
(
  [0] => this
  [1] => is
  [2] => a
  [3] => test
)
If there are missing keys in the array, then no result will be returned. This will not work:
Array
(
  [0] => this
  [1] => is
  [3] => test
)

In the previous example the
$ds = ldap.myserver.com // your ldap server
should be 
$ds = ldap_connect( "ldap.myserver.com" ) ; // your ldap server

For those debugging a wrapper, akin to symfony's client wrapper for these functions and since there is crap documentation on a full cycle of pulling a single record vs multiple, etc.
For this one:
YOU MUST call ldap_get_entries after this function call. 
AND PLEASE if you implement a wrapper, prime it with the initial entry else it makes no sense to execute without returning something easily visible as successful.
WHEN query->execute() and you get a collection.. make sure the entry field in the collection has at least the first entry primed.. wasted so much time because it was looking empty. 
AND this entire adapter needs to be wrapped with a less retarded usage pattern via an STL lib wrapper, mysticism( bad design) begone.
123.. not 4290234~"wds
Thanks for your time

This differs from ldap_search() by not recursing down to sub-entries. if you know the dn of the item you're looking for and only want info on that entry, use ldap_read() and pass it the full dn of the item you want.
It also seems that you'd alway want something like objectclass=* for the filter, since you're only searching on one entry.

Unfortunately, userPasswords seem to be NOT retrievable with ldap_read();