Net::LDAP - Lightweight Directory Access Protocol

 use Net::LDAP;

 $ldap = Net::LDAP->new( 'ldap.bigfoot.com' ) or die "$@";

 $mesg = $ldap->bind ;    # an anonymous bind

 $mesg = $ldap->search( # perform a search
                        base   => "c=US",
                        filter => "(&(sn=Barr) (o=Texas Instruments))"
                      );

 $mesg->code && die $mesg->error;

 foreach $entry ($mesg->entries) { $entry->dump; }

 $mesg = $ldap->unbind;   # take down session

 $ldap = Net::LDAP->new( 'ldap.umich.edu' );

 # bind to a directory with dn and password
 $mesg = $ldap->bind( 'cn=root, o=University of Michigan, c=us',
                      password => 'secret'
                    );

 $result = $ldap->add( 'cn=Barbara Jensen, o=University of Michigan, c=US',
                       attr => [
                         'cn'   => ['Barbara Jensen', 'Barbs Jensen'],
                         'sn'   => 'Jensen',
                         'mail' => 'b.jensen@umich.edu',
                         'objectclass' => ['top', 'person',
                                           'organizationalPerson',
                                           'inetOrgPerson' ],
                       ]
                     );

 $result->code && warn "failed to add entry: ", $result->error ;
 $mesg = $ldap->unbind;  # take down session

Net::LDAP is a collection of modules that implements a LDAP services API for Perl programs. The module may be used to search directories or perform maintenance functions such as adding, deleting or modifying entries.

This document assumes that the reader has some knowledge of the LDAP protocol.

new ( HOST, OPTIONS )

Creates a new Net::LDAP object and opens a connection to the named host. CWHOST may be a host name or an IP number. TCP port may be specified after the host name followed by a colon (such as localhost:10389). The default TCP port for LDAP is 389. You can also specify a URI, such as 'ldaps://127.0.0.1:666' or 'ldapi://%2fvar%2flib%2fldap_sock'. Note that '%2f's in the LDAPI socket path will be translated into '/'. This is to support LDAP query options like base, search etc. although the query part of the URI will be ignored in this context. If port was not specified in the URI, the default is either 389 or 636 for 'LDAP' and 'LDAPS' schemes respectively. CWHOST may also be a reference to an array of hosts, host-port pairs or URIs to try. Each will be tried in order until a connection is made. Only when all have failed will the result of CWundef be returned.

port => N

Port to connect to on the remote server. May be overridden by CWHOST.

timeout => N

Timeout passed to IO::Socket when connecting the remote server. (Default: 120)

multihomed => N

Will be passed to IO::Socket as the CWMultiHomed parameter when connecting to the remote server

localaddr => HOST

Will be passed to IO::Socket as the CWLocalAddr parameter, which sets the client's IP address (as opposed to the server's IP address.)

debug => N

Set the debug level. See the debug method for details.

async => 1

Perform all operations asynchronously.

onerror => 'die' | 'warn' | undef | sub { ... }

In synchronous mode, change what happens when an error is detected.

'die'

Net::LDAP will croak whenever an error is detected.

'warn'

Net::LDAP will warn whenever an error is detected.

undef

Net::LDAP will warn whenever an error is detected and CW-w is in effect. The method that was called will return CWundef.

sub { ... }

The given sub will be called in a scalar context with a single argument, the result message. The value returned will be the return value for the method that was called.

version => N

Set the protocol version being used (default is LDAPv3). This is useful if you want to talk to an old server and therefore have to use LDAPv2. Example

  $ldap = Net::LDAP->new( 'remote.host', async => 1 );

LDAPS connections have some extra valid options, see the start_tls method for details. Note the default value for 'sslversion' for LDAPS is 'sslv2/3', and the default port for LDAPS is 636. For LDAPI connections, HOST is actually the location of a UNIX domain socket to connect to. The default location is '/var/lib/ldapi'.

Each of the following methods take as arguments some number of fixed parameters followed by options, these options are passed in a named fashion, for example

  $mesg = $ldap->bind( "cn=me,o=example", password => "mypasswd");

The return value from these methods is an object derived from the Net::LDAP::Message class. The methods of this class allow you to examine the status of the request.

abandon ( ID, OPTIONS )

Abandon a previously issued request. CWID may be a number or an object which is a sub-class of Net::LDAP::Message, returned from a previous method call.

control => CONTROL

control => [ CONTROL, ... ]

See CONTROLS below

callback => CALLBACK

See CALLBACKS below Example

  $res = $ldap->search( @search_args );

  $mesg = $ldap->abandon( $res ); # This could be written as $res->abandon

add ( DN, OPTIONS )

Add a new entry to the directory. CWDN can be either a Net::LDAP::Entry object or a string.

attrs => [ ATTR => VALUE, ... ]

CWVALUE should be a string if only a single value is wanted, or a reference to an array of strings if multiple values are wanted. This argument is not used if CWDN is a Net::LDAP::Entry object.

control => CONTROL

control => [ CONTROL, ... ]

See CONTROLS below

callback => CALLBACK

See CALLBACKS below Example

  # $entry is an object of class Net::LDAP::Entry
  $mesg = $ldap->add( $entry );

  $mesg = $ldap->add( $dn,
                      attrs => [
                        name  => 'Graham Barr',
                        attr  => 'value1',
                        attr  => 'value2',
                        multi => [qw(value1 value2)]
                      ]
                    );

bind ( DN, OPTIONS )

Bind (log in) to the server. CWDN is the DN to bind with. An anonymous bind may be done by calling bind without any arguments.

control => CONTROL

control => [ CONTROL, ... ]

See CONTROLS below

callback => CALLBACK

See CALLBACKS below

noauth | anonymous => 1

Bind without any password. The value passed with this option is ignored.

password => PASSWORD

Bind with the given password.

sasl => SASLOBJ

Bind using a SASL mechanism. The argument given should be a sub-class of Authen::SASL. Example

  $mesg = $ldap->bind; # Anonymous bind

  $mesg = $ldap->bind( $dn, password => $password );

  # $sasl is an object of class Authen::SASL
  $mesg = $ldap->bind( $dn, sasl => $sasl, version => 3 );

compare ( DN, OPTIONS )

Compare values in an attribute in the entry given by CWDN on the server. CWDN may be a string or a Net::LDAP::Entry object.

attr => ATTR

The name of the attribute to compare.

value => VALUE

The value to compare with.

control => CONTROL

control => [ CONTROL, ... ]

See CONTROLS below.

callback => CALLBACK

See CALLBACKS below. Example

  $mesg = $ldap->compare( $dn,
                          attr  => 'cn',
                          value => 'Graham Barr'
                        );

delete ( DN, OPTIONS )

Delete the entry given by CWDN from the server. CWDN may be a string or a Net::LDAP::Entry object.

control => CONTROL

control => [ CONTROL, ... ]

See CONTROLS below.

callback => CALLBACK

See CALLBACKS below. Example

 $mesg = $ldap->delete( $dn );

moddn ( DN, OPTIONS )

Rename the entry given by CWDN on the server. CWDN may be a string or a Net::LDAP::Entry object.

newrdn => RDN

This value should be a new RDN to assign to CWDN.

deleteoldrdn => 1

This option should be passwd if the existing RDN is to be deleted.

newsuperior => NEWDN

If given this value should be the DN of the new superior for CWDN.

control => CONTROL

control => [ CONTROL, ... ]

See CONTROLS below.

callback => CALLBACK

See CALLBACKS below. Example

 $mesg = $ldap->moddn( $dn, newrdn => 'cn=Graham Barr' );

modify ( DN, OPTIONS )

Modify the contents of the entry given by CWDN on the server. CWDN may be a string or a Net::LDAP::Entry object.

add => { ATTR => VALUE, ... }

Add more attributes or values to the entry. CWVALUE should be a string if only a single value is wanted in the attribute, or a reference to an array of strings if multiple values are wanted.

delete => [ ATTR, ... ]

Delete complete attributes from the entry.

delete => { ATTR => VALUE, ... }

Delete individual values from an attribute. CWVALUE should be a string if only a single value is being deleted from the attribute, or a reference to an array of strings if multiple values are being deleted.

replace => { ATTR => VALUE, ... }

Replace any existing values in each given attribute with CWVALUE. CWVALUE should be a string if only a single value is wanted in the attribute, or a reference to an array of strings if multiple values are wanted. A reference to an empty array will remove the entire attribute.

changes => [ OP => [ ATTR => VALUE ], ... ]

This is an alternative to add, delete and replace where the whole operation can be given in a single argument. CWOP should be add, delete or replace. CWVALUE should be either a string or a reference to an array of strings, as before. Use this form if you want to control the order in which the operations will be performed.

control => CONTROL

control => [ CONTROL, ... ]

See CONTROLS below.

callback => CALLBACK

See CALLBACKS below. Example

 $mesg = $ldap->modify( $dn, add => { sn => 'Barr' } );

 $mesg = $ldap->modify( $dn, delete => [qw(faxNumber)] );

 $mesg = $ldap->modify( $dn, delete => { 'telephoneNumber' => '911' } );

 $mesg = $ldap->modify( $dn, replace => { 'mail' => 'gbarr@pobox.com' } );

 $mesg = $ldap->modify( $dn,
                        changes => [
                            # add sn=Barr
                          add     => [ sn => 'Barr' ],
                            # delete all fax numbers
                          delete  => [ faxNumber => []],
                            # delete phone number 911
                          delete  => [ telephoneNumber => ['911']],
                            # change email address
                          replace => [ mail => 'gbarr@pobox.com']
                        ]
                      );

search ( OPTIONS )

Search the directory using a given filter. This can be used to read attributes from a single entry, from entries immediately below a particular entry, or a whole subtree of entries. The result is an object of class Net::LDAP::Search.

base => DN

The DN that is the base object entry relative to which the search is to be performed.

scope => 'base' | 'one' | 'sub'

By default the search is performed on the whole tree below the specified base object. This maybe changed by specifying a CWscope parameter with one of the following values:

base

Search only the base object.

one

Search the entries immediately below the base object.

sub

Search the whole tree below (and including) the base object. This is the default.

deref => 'never' | 'search' | 'find' | 'always'

By default aliases are dereferenced to locate the base object for the search, but not when searching subordinates of the base object. This may be changed by specifying a CWderef parameter with one of the following values:

never

Do not dereference aliases in searching or in locating the base object of the search.

search

Dereference aliases in subordinates of the base object in searching, but not in locating the base object of the search.

find

Dereference aliases in locating the base object of the search, but not when searching subordinates of the base object. This is the default.

always

Dereference aliases both in searching and in locating the base object of the search.

sizelimit => N

A sizelimit that restricts the maximum number of entries to be returned as a result of the search. A value of 0, and the default, means that no restriction is requested. Servers may enforce a maximum number of entries to return.

timelimit => N

A timelimit that restricts the maximum time (in seconds) allowed for a search. A value of 0 (the default), means that no timelimit will be requested.

typesonly => 1

Only attribute types (no values) should be returned. Normally attribute types and values are returned.

filter => FILTER

A filter that defines the conditions an entry in the directory must meet in order for it to be returned by the search. This may be a string or a Net::LDAP::Filter object. Values inside filters may need to be escaped to avoid security problems; see Net::LDAP::Filter for a definition of the filter format, including the escaping rules.

attrs => [ ATTR, ... ]

A list of attributes to be returned for each entry that matches the search filter. If not specified, then the server will return the attributes that are specified as accessible by default given your bind credentials. Certain additional attributes such as createTimestamp and other operational attributes may also be available for the asking:

  $mesg = $ldap->search( ... ,
                         attrs => ['createTimestamp']
                       );

To retrieve the default attributes and additional ones, use '*'.

  $mesg = $ldap->search( ... ,
                         attrs => ['*', 'createTimestamp']
                       );

To retrieve no attributes (the server only returns the DNs of matching entries), use '1.1':

  $mesg = $ldap->search( ... ,
                         attrs => ['1.1']
                       );

control => CONTROL

control => [ CONTROL, ... ]

See CONTROLS below.

callback => CALLBACK

See CALLBACKS below. Example

 $mesg = $ldap->search(
                        base   => $base_dn,
                        scope  => 'sub',
                        filter => '(|(objectclass=rfc822mailgroup)(sn=jones))'
                      );

 Net::LDAP::LDIF->new( \*STDOUT,"w" )->write( $mesg->entries );

start_tls ( OPTIONS )

Calling this method will convert the existing connection to using Transport Layer Security (TLS), which provides an encrypted connection. This is only possible if the connection uses LDAPv3, and requires that the server advertizes support for LDAP_EXTENSION_START_TLS. Use supported_extension in Net::LDAP::RootDSE to check this.

verify => 'none' | 'optional' | 'require'

How to verify the server's certificate:

none

The server may provide a certificate but it will not be checked - this may mean you are be connected to the wrong server

optional

Verify only when the server offers a certificate

require

The server must provide a certificate, and it must be valid. If you set verify to optional or require, you must also set either cafile or capath. The most secure option is require.

sslversion => 'sslv2' | 'sslv3' | 'sslv2/3' | 'tlsv1'

This defines the version of the SSL/TLS protocol to use. Defaults to 'tlsv1'.

ciphers => CIPHERS

Specify which subset of cipher suites are permissible for this connection, using the standard OpenSSL string format. The default value is 'ALL', which permits all ciphers, even those that don't encrypt.

clientcert => '/path/to/cert.pem'

clientkey => '/path/to/key.pem'

keydecrypt => sub { ... }

If you want to use the client to offer a certificate to the server for SSL authentication (which is not the same as for the LDAP Bind operation) then set clientcert to the user's certificate file, and clientkey to the user's private key file. These files must be in PEM format. If the private key is encrypted (highly recommended) then keydecrypt should be a subroutine that returns the decrypting key. For example:

 $ldap = Net::LDAP->new( 'myhost.example.com', version => 3 );
 $mesg = $ldap->start_tls(
                           verify => 'require',
                           clientcert => 'mycert.pem',
                           clientkey => 'mykey.pem',
                           keydecrypt => sub { 'secret'; },
                           capath => '/usr/local/cacerts/'
                         );

capath => '/path/to/servercerts/'

cafile => '/path/to/servercert.pem'

When verifying the server's certificate, either set capath to the pathname of the directory containing CA certificates, or set cafile to the filename containing the certificate of the CA who signed the server's certificate. These certificates must all be in PEM format. The directory in 'capath' must contain certificates named using the hash value of the certificates' subject names. To generate these names, use OpenSSL like this in Unix:

    ln -s cacert.pem `openssl x509 -hash -noout < cacert.pem`.0

(assuming that the certificate of the CA is in cacert.pem.)

unbind ( )

The unbind method does not take any parameters and will unbind you from the server. Some servers may allow you to re-bind or perform other operations after unbinding. If you wish to switch to another set of credentials while continuing to use the same connection, re-binding with another DN and password, without unbind-ing, will generally work. Example

 $mesg = $ldap->unbind;

The following methods are for convenience, and do not return CWNet::LDAP::Message objects.

async ( VALUE )

If CWVALUE is given the async mode will be set. The previous value will be returned. The value is true if LDAP operations are being performed asynchronously.

certificate ( )

Returns an X509_Certificate object containing the server's certificate. See the IO::Socket::SSL documentation for information about this class. For example, to get the subject name (in a peculiar OpenSSL-specific format, different from RFC 1779 and RFC 2253) from the server's certificate, do this:

    print "Subject DN: " . $ldaps->certificate->subject_name . "\n";

cipher ( )

Returns the cipher mode being used by the connection, in the string format used by OpenSSL.

debug ( VALUE )

If CWVALUE is given the debug bit-value will be set. The previous value will be returned. Debug output will be sent to CWSTDERR. The bits of this value are:

 1   Show outgoing packets (using asn_hexdump).
 2   Show incoming packets (using asn_hexdump).
 4   Show outgoing packets (using asn_dump).
 8   Show incoming packets (using asn_dump).

The default value is 0.

disconnect ( )

Disconnect from the server

root_dse ( OPTIONS )

The root_dse method retrieves cached information from the server's rootDSE.

attrs => [ ATTR, ... ]

A reference to a list of attributes to be returned. If not specified, then the following attributes will be requested

  subschemaSubentry
  namingContexts
  altServer
  supportedExtension
  supportedFeatures
  supportedControl
  supportedSASLMechanisms
  supportedLDAPVersion

The result is an object of class Net::LDAP::RootDSE. Example

 my $root = $ldap->root_dse;
 # get naming Context
 $root->get_value( 'namingContext', asref => 1 );
 # get supported LDAP versions
 $root->supported_version;

As the root DSE may change in certain circumstances - for instance when you change the connection using start_tls - you should always use the root_dse method to return the most up-to-date copy of the root DSE.

schema ( OPTIONS )

Read schema information from the server. The result is an object of class Net::LDAP::Schema. Read this documentation for further information about methods that can be performed with this object.

dn => DN

If a DN is supplied, it will become the base object entry from which the search for schema information will be conducted. If no DN is supplied the base object entry will be determined from the rootDSE entry. Example

 my $schema = $ldap->schema;
 # get objectClasses
 @ocs = $schema->all_objectclasses;
 # Get the attributes
 @atts = $schema->all_attributes;

socket ( )

Returns the underlying CWIO::Socket object being used.

sync ( MESG )

Wait for a given CWMESG request to be completed by the server. If no CWMESG is given, then wait for all outstanding requests to be completed. Returns an error code defined in Net::LDAP::Constant.

version ( )

Returns the version of the LDAP protocol that is being used.

Many of the methods described above accept a control option. This allows the user to pass controls to the server as described in LDAPv3.

A control is a reference to a HASH and should contain the three elements below. If any of the controls are blessed then the method CWto_asn will be called which should return a reference to a HASH containing the three elements described below.

type => OID

This element must be present and is the name of the type of control being requested.

critical => FLAG

critical is optional and should be a boolean value, if it is not specified then it is assumed to be false.

value => VALUE

If the control being requested requires a value then this element should hold the value for the server.

Most of the above commands accept a callback option. This option should be a reference to a subroutine. This subroutine will be called for each packet received from the server as a response to the request sent.

When the subroutine is called the first argument will be the Net::LDAP::Message object which was returned from the method.

If the request is a search then multiple packets can be received from the server. Each entry is received as a separate packet. For each of these the subroutine will be called with a Net::LDAP::Entry object as the second argument.

During a search the server may also send a list of references. When such a list is received then the subroutine will be called with a Net::LDAP::Reference object as the second argument.

Net::LDAP also exports constants for the error codes that can be received from the server, see Net::LDAP::Constant.

Net::LDAP::Constant, Net::LDAP::Control, Net::LDAP::Entry, Net::LDAP::Filter, Net::LDAP::Message, Net::LDAP::Reference, Net::LDAP::Search, Net::LDAP::RFC

The homepage for the perl-ldap modules can be found at http://perl-ldap.sourceforge.net/

This document is based on a document originally written by Russell Fulton <r.fulton@auckland.ac.nz>.

Chris Ridd <chris.ridd@isode.com> for the many hours spent testing and contribution of the ldap* command line utilities.

A discussion mailing list is hosted by sourceforge at <perl-ldap@perl.org> No subscription is necessary!

We hope you do not find any, but if you do please report them to the mailing list.

If you have a patch, please send it as an attachment to the mailing list.

Graham Barr <gbarr@pobox.com>

Copyright (c) 1997-2004 Graham Barr. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.