Create an LDAP Address Book Page 2

Create LDAP Query

As mentioned previously, LDAP queries are not much like SQL queries. Therefore, the
syntax may seem a bit limiting, but here is a basic example and one that works in
this scenario.

//Create Query
$ldap_query = "cn=$common";

In our example “cn” is the attribute on which we are performing the search,
and $common is the search string variable from the search form. LDAP query
syntax allows for wildcard matching using ‘*’. For example, ‘*stanley’ will find
‘dan stanley’.

Connect to LDAP Server

The given function connects
to an LDAP resource and assigns the connection link identifier to a variable, much like connecting to a regular database, like MySQL.

<?php
//Connect to LDAP
$connect_id = ldap_connect($LDAP_SERVER[$SERVER_ID]);
?>

In our example, “$connect_id” is the link identifier, $LDAP_SERVER is the
array of possible ldap servers,
and $SERVER_ID is the LDAP server variable from the search form.

Process Query if Connection Was Successful

If our connection was successful, we will have a valid LDAP link identifier and
we can process the query.

<?php
if($connect_id)
  {
  //Authenticate
  $bind_id = ldap_bind($connect_id);
  //Perform Search
  $search_id = ldap_search($connect_id, $LDAP_ROOT_DN[$SERVER_ID], $ldap_query);
  //Assign Result Set to an Array
  $result_array = ldap_get_entries($connect_id, $search_id);
  }
else
  {
  //Echo Connection Error
  echo "Could not connect to LDAP server: $LDAP_SERVER[$SERVER_ID]";
  }
?>

Once we have established a connection to the LDAP services, we must identify ourselves.
Most database connections with PHP send the username and password with the connection.
However, with LDAP, credentials are unknown until a bind is performed.
In our example, “$bind_id” is the bind link identifier. We are performing an anonymous
bind to the public LDAP servers. Therefore, no argument is sent to ldap_bind() accept
the connection link identifier.

After we have been authorized, via bind as anonymous, we perform the query using the
ldap_search() function. $search_id is created and is our search link identifier.

Then, we assign our result set to the variable $result_array using the function
ldap_get_entries(). This will allow us to sort the information in a logical
manner for display.