[Fwd] Preannouncing 1st alpha DBD::Ldap release!

[Graham B. <gb...@va...>]

This is an interesting idea


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Date: Wed, 06 Jun 2001 14:27:08 -0400
From: tur...@ne...
To: db...@pe...
Subject: Preannouncing 1st alpha DBD::Ldap release!
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Greetings,

    I am proud to release the very 1st alpha version of DBD::Ldap!  
This module is designed to allow one to access LDAP (Lightweight Directory 
Access Protocol) databases using traditional SQL and Perl and DBI.  It is 
hoped that someone (besides me) will find this code useful.  This is my 
very 1st release, so it has only been gently tested by me on my 
own OpenLDAP server using Linux Mandrake 7.2 and Perl 5.6.0.  Most of the 
code was transcribed from my 1st and only other DBD module DBD::Sprite. 
This version of the module and early updates are available on my website: 
http://turnerville.virtualave.net -- I wanted to announce here and get 
a few replies before unleashing a version on CPAN.

Enjoy & Thanks for any feedback!


Jim Turner

-------------------- README ----------------------
NAME

    DBD::Ldap - A DBI driver for LDAP databases.  LDAP stands for the 
    "Lightweight Directory Access Protocol".  For more information, 
    see:  http://www.ogre.com/ldap/docs.html

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();

WARNING

    THIS IS ALPHA SOFTWARE. It is *only* 'Alpha' because this is it's 1st 
    release!

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).  

JLdap.pm is included in this module as a separate file, and is required.

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".

Prerequisites

    Convert::Ans1   (required by Net::LDAP)
    Net::LDAP
    DBI
    - an LDAP database to connect to.

Installation

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

        gzip -cd DBD-Ldap-0.1000.tar.gz | tar xf -

    (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. the ExtUtils::MakeMaker
    manpage.

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('list_tables');

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).
    
AUTHOR AND COPYRIGHT

    This module is Copyright (C) 2000 by

        Jim Turner

        Email: jim...@lm...

    All rights reserved.

    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.

    JLdap.pm is a derived work by Jim Turner from Ldap.pm, a module 
    written and copyrighted (c) 1995-1998, by Shishir Gurdavaram 
    (sh...@or...).

SEE ALSO

    Net::LDAP(3), DBI(3), perl(1)
   
    For general information on DBI see

      http://www.symbolstone.org/technology/perl/DBI


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