DBD::LDAP

Section: User Contributed Perl Documentation (3)
Updated: 2006-10-25
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NAME

     DBD::LDAP - Perl extension for DBI, providing an SQL/Perl DBI interface 
     to Ldap databases.  LDAP stands for the "Lightweight Directory Access 
     Protocol".  For more information, see:  http://www.ogre.com/ldap/docs.html

 

AUTHOR

    This module is Copyright (C) 2000-2004 by

                Jim Turner

        Email:  turnerjw@wwol.com

    All rights reserved Without Prejudice.

    You may distribute this module under the terms of either the GNU General
    Public License or the Artistic License, as specified in the Perl README
    file.

 

PREREQUISITES

        Convert::ANS1   (required by Net::LDAP)
        Net::LDAP
        DBI
        - an LDAP database to connect to.

 

SYNOPSIS

     use DBI;
     $dbh = DBI->connect("DBI:LDAP:ldapdb",'user','password')  #USER LOGIN.
         or die "Cannot connect as user: " . $DBI::errstr;

     $dbh = DBI->connect("DBI:LDAP:ldapdb")  #ANONYMOUS LOGIN (Read-only).
         or die "Cannot connect as guest (readonly): " . $DBI::errstr;

     $sth = $dbh->prepare("select * from people where (cn like 'Smith%')")
         or die "Cannot prepare: " . $dbh->errstr();
     $sth->execute() or die "Cannot execute: " . $sth->errstr();
         while ((@results) = $sth->fetchrow_array)
         {
                 print "--------------------------------------------------------\n";
                 ++$cnt;
                 while (@results)
                 {
                         print "------>".join('|',split(/\0/, shift(@results)))."\n";
                 }
         }
     $sth->finish();
     $dbh->disconnect();

 

DESCRIPTION

DBD::LDAP is a DBI extension module adding an SQL database interface to standard LDAP databases to Perl's database-independent database interface. You will need access to an existing LDAP database or set up your own using an LDAP server, ie. ``OpenLDAP'', see (http://www.openldap.org).

The main advantage of DBD::LDAP is the ability to query LDAP databases via standard SQL queries in leu of cryptic LDAP ``filters''. LDAP is optimized for quick lookup of existing data, but DBD::LDAP does support entry inserts, updates, and deletes with commit/rollback via the standard SQL commands!

LDAP databases are ``heirarchical'' in structure, whereas other DBD-supported databases are ``relational'' and there is no LDAP-equivalent to SQL ``tables'', so DBD::LDAP maps a ``table'' interface over the LDAP ``tree'' via a configuration file you must set up. Each ``table'' is mapped to a common ``base DN''. For example, consider a typical LDAP database of employees within different departments within a company. You might have a ``company'' names ``Acme'' and the root ``dn'' of ``dc=Acme, dc=com'' (Acme.com). Below the company level, are divisions, ie. ``Widgets'', and ``Blivets''. Each division would have an entry with a ``dn'' of ``ou=Widgets, dc=Acme, dc=com''. Employees within each division could have a ``dn'' of ``cn=John Doe, ou=Widgets, dc=Acme, dc=com''. With DBD::LDAP, we could create tables to access these different levels, ie. ``top'', which would have a ``DN'' of ``dc=Acme, dc=com'', ``WidgetDivision'' for ``dc=Acme, dc=com''. Tables can also be constained by additional attribute specifications (filters), ie constraining by ``objectclass'', ie. ``(objectclass=person)''. Then, doing a ``select * from WidgetDivision'' would display all ``person''s with a ``dn'' containing "``ou=Widgets, dc=Acme, dc=com''.  

INSTALLATION

    Installing this module (and the prerequisites from above) is quite
    simple. You just fetch the archive, extract it with

        gzip -cd DBD-LDAP-####.tar.gz | tar xf -

                -or-

                tar -xzvf DBD-LDAP-####.tar.gz

    (this is for Unix users, Windows users would prefer WinZip or something
    similar) and then enter the following:

        cd DBD-LDAP-#.###
        perl Makefile.PL
        make
        make test

    If any tests fail, let me know. Otherwise go on with

        make install

    Note that you almost definitely need root or administrator permissions.
    If you don't have them, read the ExtUtils::MakeMaker man page for
    details on installing in your own directories.

 

GETTING STARTED:

        1) Create a "database", ie. "foo" by creating a text file "foo.ldb".  The 
        general format of this file is:

---------------------------------------------------------- hostname[;port][:[root-dn][:[loginrule]]] tablename1:[basedn]:[basefilter]:dnattrs:[visableattrs]:[insertattrs]:[ldap_options] tablename2:[basedn]:[basefilter]:dnattrs:[visableattrs]:[insertattrs]:[ldap_options] ... ----------------------------------------------------------

        <hostname>              represents the ldap server host name.
        <port>                  represents the server's port, default is 389.
        <root-dn>                       if specified, is appended to the end of each tablename's 
                                base-dn.
        <loginrule>     if specified, converts single word "usernames" to the 
                                appropriate DN, ie:

                        "cn=*,<ROOT>" would convert user name "foo" to "cn=foo, " and 
                        append the "<root-dn>" onto that.  The asterisk is converted to 
                        the user-name specified in the "connect" method.  If not specified, 
                        the username specified in the "connect" method must be a full DN.
                        If the "<root-dn>" is not specified, then the "<loginrule>" would 
                        need to be a full DN.

        tablename       -       represents the name to be used in SQL statements for a given 
                        set of entries which make up a virtual "table".
        basedn - if specified, is appended to the "<root-dn>" to make up the 
                        common base DN for all entries in this table.  If "<root-dn>" is 
                        not specified, then a full DN must be specified; otherwise, the 
                        default is the root-dn.
        basefilter      - if specified, specifies a filter to be used if no "where"-
                        clause is specified in SQL queries.  If a "where"-clause is 
                        specified, the resulting filter is "and"-ed with this one.  The 
                        default is "(objectclass=*)".
        dnattrs - specifies which attributes that values for which are to be 
                        appended to the left of the basedn to create DNs for new entries 
                        being inserted into the table.
        visableattrs - if specified, one or more attributes separated by commas 
                        which will be sought when the SQL statement does not specify 
                        attributes, ie. "select * from tablename".  If not specified, the 
                        attributes of the first matching entry are returned and used for 
                        all entries matching a given query.
        insertattrs - if specified, one or more attribute/value combinations to be 
                        added to any new entry inserted into the table, usually needed for 
                        objectclass values.  The attributes and values usually correspond 
                        to those specivied in the "<basefilter>".  The general format is: 
                        attr1=value1[|value2...],attr2=value1...,...
                        These attributes and values will be joined with any user-specified 
                        values for these attributes.
        ldap_options - if specified, can be any one or more of the following:

                ldap_sizelimit - Limit the number of entries fetch by a query to this 
                                number (0 = no limit) - default:  0.
                ldap_timelimit - Limit the search to this number of seconds per query. 
                                (0 = no limit) - default:  0.
                ldap_scope - specify the "scope" of the search.  Values are:  "base", 
                                "one", and "sub", see Net::LDAP docs.  Default is "one", 
                                meaning the set of records one level below the basedn.  "base" 
                                means search only the basedn, and "sub" means the union 
                                of entries at the "base" level and "one" level below.
                ldap_inseparator - specify the separator character/string to be used 
                                in queries to separate multiple values being specified for 
                                a given attribute.  Default is "|".
                ldap_outseparator - specify the separator character/string to be used 
                                in queryies to separate multiple values displayed as a result 
                                of a query.  Default is "|".
                ldap_firstonly - only display the 1st value fetched for each attribute 
                                per entry.  This makes "ldap_outseparator" unnecessary.

        2) write your script to use DBI, ie:

                #!/usr/bin/perl
                use DBI;

                $dbh = DBI->connect('DBD:LDAP:mydb','me','mypassword') || 
                                die "Could not connect (".$DBI->err.':'.$DBI->errstr.")!";
                ...
                #CREATE A TABLE, INSERT SOME RECORDS, HAVE SOME FUN!

        3) get your application working.

 

INSERTING, FETCHING AND MODIFYING DATA

        1st, we'll create a database called "ldapdb" with the tables previously 
        mentioned in the example in the DESCRIPTION section:

----------------- file ``ldapdb.ldb'' ---------------- ldapserver:dc=Acme, dc=com:cn=*,<ROOT> top:::dc WidgetDivision:ou=Widgets, :&(objectclass=top)(objectclass=person):cn:cn,sn,ou,title,telephonenumber,description,objectclass,dn:objectclass=top|person|organizationalPerson:ldap_outseparator => ``:'' ----------------------------------------------------

    The following examples insert some data in a table and fetch it back:
    First all data in the string:

        $dbh->do(<<END_SQL);
        INSERT INTO top (ou, cn, objectclass)  
        VALUES ('Widgets', 'WidgetDivision', 'top|organizationalUnit')
END_SQL

    Next an example using parameters:

        $dbh->do("INSERT INTO WidgetDivision (cn,sn,title,telephonenumber) VALUES (?, ?, ?, ?)",
        'John Doe','DoeJ','Manager','123-1111');
END_SQL
        $dbh->commit();

        NOTE:  Unlike most other DBD modules which support transactions, changes 
                made do NOT show up until the "commit" function is called, unless 
                "AutoCommit" is set.  This is due to the fact that fetches are done 
                from the LDAP server and changes do not take effect there until the 
                Net::LDAP "update" function is called, which is called by "commit".

        NOTE: The "dn" field is generated automatically from the base "dn" and the 
                dn component fields specified by "dnattrs", If you try to insert a 
                value directly into it, it will be ignored.  Also, if not specified, 
                any attribute/value combinations specified in the "insertattrs" 
                option will be added automatically.

    To retrieve data, you can use the following:

        my($query) = "SELECT * FROM WidgetDivision WHERE cn like 'John%' ORDER BY cn";
        my($sth) = $dbh->prepare($query);
        $sth->execute();
        while (my $entry = $sth->fetchrow_hashref) {
            print("Found result record: cn = ", $entry->{'cn'},
                  ", phone = ", $row->{'telephonenumber'});
        }
        $sth->finish();

        The SQL "SELECT" statement above (combined with the table information 
        in the "ldapdb.ldb" database file would generate and execute the following 
        equivalent LDAP Search:

                base => 'ou=Widgets, dc=Acme, dc=com',
                filter => '(&(&(objectclass=top)(objectclass=person))(cn=John*))',
                scope => 'one',
                attrs => 'cn,sn,ou,title,telephonenumber,description,objectclass,dn'

    See the DBI(3) manpage for details on these methods. See the

    Data rows are modified with the UPDATE statement:

        $dbh->do("UPDATE WidgetDivision SET description = 'Outstanding Employee' WHERE cn = 'John Doe'");

        NOTE:  You can NOT change the "dn" field directly - direct changes will be 
                ignored.  You change the "rdn" component of the "dn" field by changing 
                the value of the other field(s) which are appended to the base "dn".
                Also, if not specified, any attribute/value combinations specified in 
                the "insertattrs" option will be added automatically.

    Likewise you use the DELETE statement for removing entries:

        $dbh->do("DELETE FROM WidgetDivision WHERE description = 'Outstanding Employee'");

 

METADATA

    The following attributes are handled by DBI itself and not by DBD::LDAP,
    thus they should all work as expected.

        PrintError
        RaiseError
        Warn

    The following DBI attributes are handled by DBD::LDAP:

    AutoCommit
        Works

    NUM_OF_FIELDS
        Valid after '$sth->execute'

    NUM_OF_PARAMS
        Valid after '$sth->prepare'

    NAME
        Valid after '$sth->execute'; undef for Non-Select statements.

    NULLABLE
        Not really working. Always returns an array ref of one's, as
        DBD::LDAP always allows NULL (handled as an empty string). 
        Valid after `$sth->execute'.

    LongReadLen
                Should work

    LongTruncOk
                Should work

    These attributes and methods are not supported:

        bind_param_inout
        CursorName

    In addition to the DBI attributes, you can use the following dbh
    attributes.  These attributes are read-only after "connect".

        ldap_dbuser
                Current database user.

        ldap_HOME
                Environment variable specifying a path to search for LDAP 
                databases (*.sdb) files.

 

DRIVER PRIVATE METHODS

    DBI->data_sources()
        The `data_sources' method returns a list of "databases" (.ldb files) 
        found in the current directory and, if specified, the path in 
        the ldap_HOME environment variable.

    $dbh->tables()
        This method returns a list of table names specified in the current 
        database.
        Example:

            my($dbh) = DBI->connect("DBI:LDAP:mydatabase",'me','mypswd');
            my(@list) = $dbh->func('tables');

 

OTHER SUPPORTING UTILITIES

 

RESTRICTIONS

        DBD::LDAP currently treats all data as strings and all fields as 
        VARCHAR(255).

        Currently, you must define tables manually in the "<database>.ldb" file 
        using your favorite text editor.  I hope to add support for the SQL 
        "Create Table", "Alter Table", and "Drop Table" functions to handle this 
        eventually.

 

TODO

        "Create Table", "Alter Table", and "Drop Table" SQL functions for 
        creating, altering, and deleting the tables defined in the 
        "<database>.ldb" file.

        Some kind of datatype support, ie. numeric (for sorting), CHAR for padding, 
        Long/Blob - for >255 chars per field, etc.

 

KNOWN BUGS

        none - (yet).

 

SEE ALSO

        Net::LDAP(3), DBI(3), perl(1)


 

Index

NAME
AUTHOR
PREREQUISITES
SYNOPSIS
DESCRIPTION
INSTALLATION
GETTING STARTED:
INSERTING, FETCHING AND MODIFYING DATA
METADATA
DRIVER PRIVATE METHODS
OTHER SUPPORTING UTILITIES
RESTRICTIONS
TODO
KNOWN BUGS
SEE ALSO

linux.jgfs.net manual pages