[Omaha.pm] Learning perl - working with LDAP

[Theodore Katseres]

On Fri, Feb 24, 2012 at 10:36 AM, Bill Brush <bbrush at gmail.com> wrote:

> Hello everyone.  I just recently started down the path of learning
> Perl, and I'm working on my first script (program?  which is the
> correct term for Perl?).
>
> Anyway, I'm basing it on the example here:
>
> http://www.developer.com/open/article.php/10930_3106601_3/Searching-Active-Directory-with-Perl.htm
>
> Getting down to the details of the code, I want to throw out some
> lines and how I interpret them to make sure I'm reading them right.
>
> This line seems to be the money line of the example:
>
> my $results = $ad->search(base=>$base,filter=>$filter,attrs=>$attrs);
>
> The way I read that is:
>
> my $results  =  (the output of this command will be stored in $results)
>
> $ad->search   (Use the search method in the previously created object $ad)
>
> (base=>$base,filter=>$filter,attrs=>$attrs)  (The search method has 3
> inputs required [base,filter, attrs] which are stored in the 3
> variables.  Base corresponds to the LDAP context where the search will
> be performed, filter gives the criteria of the objects selected, and
> attrs gives the attributes to be returned.  Presumably these could
> have been written out explicitly rather than stored in variables, but
> this is infinitely more readable and flexible.)
>
> So am I reading that command correctly?
>

Yes.


> Another question about the example script is minor, but I haven't
> found the answer elsewhere.  The author uses the operator .= (dot
> equal).  What does that do?
>

$x = 'x';
$x .= 'X';

is short had for

$x = $x . 'X';

both store 'xX' after execution.


> A final question is more of a code style and efficiency question.  The
> author uses a FOR-NEXT loop to cycle through the alphabet.  Wouldn't a
> While (letter<z) or Until (letter =z) loop structure be more concise?
> I'm trying to understand if there's an advantage to the author's
> method that I'm not grasping.
>

I would propose rather than incrementing a letter index you could just use
'a'..'z' range operator.

This is how I would code the example.

#!/usr/bin/perl
use Modern::Perl;
use Net::LDAP;

# Connect and bind
my $ad = Net::LDAP->new("ad.wjgilmore.com") || die "Could not connect!";
$ad->bind( 'ad-web at ad.wjgilmore.com', password => 'secret' );

# build the alphabetical toc
my $toc = "\n\n" . join( ' ', a .. z ) . " \n";

# Perform LDAP queries, build directory pages
my $base = 'OU=People,OU=staff,DC=ad,DC=wjgilmore,DC=com';
for my $letter ( a .. z ) {

    # Filter on the staff membership and
    # first letter of samaccountname attribute
    my $filter =
"(&(memberof=CN=staff,OU=groups,DC=ad,DC=wjgilmore,DC=com)(samaccountname=$letter*))";

    # Which attributes should be returned?
    my $attrs = "sn, givenname, mail";

    # Execute the search
    my $results = $ad->search( base => $base, filter => $filter, attrs =>
$attrs );

    # Check for errors!
    $results->code && die $results->error;

    # Build the directory
    my $directory;
    for my $entry ( $results->entries ) {
        $directory .= sprintf '%s %s (%s)%s',
$entry->get_value('givenname'), $entry->get_value('sn'),
            $entry->get_value('mail'), "\n";
    }

    # Write the file
    open( FILE, '>', "/www/wjgilmore/directory/$letter.html" );
    say FILE $toc, $directory;
    close FILE;
}

# Unbind from the server
$ad->unbind;
# END

-- 
Ted Katseres
      ||=O=||
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