1. LDAP APIs
CNS 4650
Fall 2004
Rev. 2

2. LDAP C APIs
OpenLDAP
Mozilla/Netscape
Novell LDAP SDK
Microsoft ADSI

3. LDAP C APIs Most of the LDAP C SDKs are similar Based of the LDAP RFC
Usually slight difference between each

4. PERL LDAP API Original PERL LDAP API was PerLDAP
Net::LDAP preferred API
Net::LDAP does not require a C compiler to install

5. Other APIs
PHP
Python
Java

6. Basic LDAP Search Steps
Create connection
Bind (if needed)
Perform search
Display results
Close connection

7. Create Connection C API PERL API ld - LDAP Handle
#include <ldap.h>
LDAP *ld //LDAP Handle
ld = ldap_init(”ldap.somewhere.com”, 389);
use Net::LDAP;
my $conn = new Net::LDAP("tux.sinemas.net");
ld - LDAP Handle
ldap_init() - allocate LDAP handle
ldap_open() is also available. But, eventually it will be dropped. ldap_init() is preferred because a LDAP handle is allocated but no connection occurs.
conn - LDAP Handle
Net::LDAP() - allocate LDAP handle

8. Bind (if necessary) C API PERL API rc - integer return value
...
rc = ldap_simple_bind_s(ld, MY_DN, MY_PWD);
...
$conn->bind(dn=>MY_DN,password=>MY_PWD)
rc - integer return value
ldap_simple_bind_s() - simple bind
ld - LDAP Handle
MY_DN: dn of user to authenticate
MY_PWD: password of user
There are other ldap_bind_* functions for SASL, Kerberos IV, etc.
conn - LDAP Handle
conn->bind() - simple bind

9. Perform Search C API PERL API rc - integer return value
...
rc = ldap_search(ld, base, scope, filter, attrs, attrsonly);
...
$mesg = $conn->search(base=>base,scope=>scope,
filter=>filter, attrs=>attrs);
rc - integer return value
ldap_search() - search
ld - LDAP Handle
base: where to search from (ou=dev)
scope: LDAP_SCOPE_ONELEVEL or LDAP_SCOPE_SUB
filter: What to look for
attrs: what I want returned
attrsonly: 0 or 1 return attribute name and values
mesg - Search return value
conn->search() - search
base: where to search from (ou=dev)
scope: sub or onelevel
filter: What to look for
attrs: what I want returned

10. Search Filters Filter is encased in ( ) Wildcard - * Boolean Examples
& - AND
| - OR
! - NOT
Examples
(cn=Dan Sinema)
(&(cn=Dan Sinema)(objectclass=user))
(cn=Dan *)

11. Perform Search C API PERL API rc - integer return value
...
rc = ldap_search(ld, base, scope, filter, attrs, attrsonly);
...
$mesg = $conn->search(base=>base,scope=>scope,
filter=>filter, attrs=>attrs);
rc - integer return value
ldap_search() - search
ld - LDAP Handle
base: where to search from (ou=dev)
scope: LDAP_SCOPE_ONELEVEL or LDAP_SCOPE_SUB
filter: What to look for
attrs: what I want returned
attrsonly: 0 or 1 return attribute name and values
mesg - Search return value
conn->search() - search
base: where to search from (ou=dev)
scope: sub or onelevel
filter: What to look for
attrs: what I want returned

12. Display Results C API result, e: LDAPMessage structure
LDAPMessage *result, e;
char* attribute;
BerElement *ber;
char** vals;
...
e = ldap_first_entry(ld, result )
attribute = ldap_first_attribute(ld, e, ber )
vals = ldap_get_values(ld, e, attribute)
result, e: LDAPMessage structure
attribute: char string
ber - BER structure (LDAP returns data BER encoded)
vals: array of strings
ldap_first_entry(): Get first returned entry, use ldap_next_entry() after
ldap_first_attribute(): Get the first attribute of the entry
ldap_get_values(): Get the attribute values

13. Display Results PERL API
...
$ldif = new Net::LDAP::LDIF("-","w");
for ($i = 0; $i < $mesg->count; $i++) {
my $entry = $mesg->entry($i);
$ldif->write_entry($entry); }
$ldif->done;
ldif - allows printing of entries in LDIF format
mesg - LDAP Handle
entry - Entry contained in the LDAP Handle
ldif->write_entry() - write in an LDIF format

14. Close Connections C API PERL API rc - integer return value
...
rc = ldap_unbind(ld);
...
$conn->unbind;
rc - integer return value
ldap_unbind() - destroy LDAP handle
ld - LDAP Handle
conn - LDAP Handle
conn->unbind() - destroy LDAP Handle

15. Resources http://www.openldap.org - Manual Pages (C Language)
- Source Code (PERL)