Recently in Perl Category

Für jedes Formular im Internet verwende ich eine eigene Catchall-Email-Adresse. So kann ich nachvollziehen welcher Anbieter welche Newsletter zu verantworten hat. Mittlerweile haben sich einige E-Mail Adressen derart verbreitet, dass ich darüber täglich Newsletter von irgendwelchen mir nicht bekannten Anbietern bekomme. Das Abmelden des jeweiligen Newsletters bringt wenig, da ein paar Tage später ein anderer Newsletter eines anderen Anbieters über diese Adresse verschickt wird.

Deswegen kann ich nun jede Adresse mittels PCRE dediziert blocken wie folgt:

io:/etc/postfix# cat header_checks 
/^to: *(citibank|r|microsoft|macbookpro)@mx\.buetow\.org/ 
    REJECT WTF! Don't send spam!
/^to: *(wizzair|christopher)@paul\.buetow\.org/ 
    REJECT WTF! Don't send spam!
/^subject:.*VIAGRA/ 
    REJECT Instead of Viagra I need Beer for free!

io:/etc/postfix# grep header_check main.cf
header_checks = regexp:/etc/postfix/header_checks

sub ev
{
    my $term = $_[0];
    if($term =~ /^$con/)
    {
        return Return($1);
    }
    elsif($term=~/^$div/)
    {
        my $numer=$1; my $denom=$3;
        return DO {
                    my $n <- ev($numer);
                    my $d <- ev($denom);
                    my $g <- tick();
                    Return( $n / $d );
                  }
    }else{die "Syntax Error: $term";}
}

dns.buetow.org shows a list of all free available short .de domains (up to 3 characters). it's updating automatically every 3 days.

it's driven by a perl script of mine using a sqlite database as its backend.

Xerl is an open source website template engine (TE) with some features of a Content Management System (CMS) programmed in object oriented Perl and using XML.

It now supports the redirect:* directive. Which allows me to configure HTTP redirects from one host to another without using mod_rewrite or .htaccess. redirect:* is working like the alias:* directive of the previous feature upgrade.

One small step for Xerl - one giant step against duplicated content.

I've committed Xerl Revision number 170 to the subversion repository. Xerl is an open source website template engine (TE) with some features of a Content Management System (CMS) programmed in object oriented Perl and using XML.

Enhancements made:

• Host aliases can now be configured using an alias:hostname file. E.g.:

  echo www.buetow.org > hosts/alias:buetow.org

  would create the host buetow.org as an alias to www.buetow.org. Means: buetow.org shows the same content as www.buetow.org. My hosts/ directory now looks like this (alias:* are host alias definitions and the rest are directories for the "real" virtual hosts):

  alias:buetow.org               fype.buetow.org
  alias:butow.org                irssi.buetow.org
  alias:dslvpnrouter.buetow.org  jsmstrade.buetow.org
  alias:pb-labs.com              lan.buetow.org
  alias:perl9.org                netcalendar.buetow.org
  alias:www.butow.org            niduterm.buetow.org
  alias:www.pb-labs.com          paul.buetow.org
  alias:www.xn--btow-0ra.com     perlchat.buetow.org
  alias:www.xn--btow-0ra.org     stud.buetow.org
  alias:xn--btow-0ra.com         use.perl9.org
  alias:xn--btow-0ra.org         vpndslrouter.buetow.org
  awksite.buetow.org             vs-sim.buetow.org
  bg.buetow.org                  www.buetow.org
  blogs.buetow.org               www.perl9.org
  calculator.buetow.org          xerl.buetow.org
  curses.buetow.org              ychat.buetow.org
  default                        yhttpd.buetow.org
  fuzzybot.buetow.org

  Because of duplicated content, the next version of Xerl may use a HTTP redirect instead (search engines). The old way of defining aliases still works as well:

  echo buetow.org=www.buetow.org >> conf.txt

  However this method is not the preferred anymore. conf.txt needs to get restructured anyway.

• Initial support for plugins

• Some code review including more documentations about the coding style to use.

Xerl is work in progress! It has no real documentation and no release available atm. This is mostly a hobby project fitting my own needs in having dynamic websites.

I've created a new subdomain for the Irssi IRC client: irssi.buetow.org. It will contain all my Perl plugins written for it. At the moment I've only one plugin to offer: drunken.pl. The base code of it also has been discussed on PerlMonks. After playing around I decided to do a plugin for myself ;) It is my first plugin for Irssi, because I just made the switch from BitchX to Irssi. I should 've done this earlier :(

Recently, I managed to program a few cosmetics fixes for the Xerl Template Engine. Xerl is a website template engine written in Perl and designed to use XML as its primary source for content and configurations.

• Xerl is not logging any IP addreses anymore. Xerl is now logging hashsums of those instead.
• Xerls logging internals have been improved.
• Lots of other small but nice cosmetic fixes have been introduced.

As a user, nobody will recognize any of those changes. I wanted to mention recent work in order to show that Xerl is not dead. However, the progress of development is slow but constant.

I've the original version of this book several years already. But it is great that this book is now available for anyone as a free download. This book covers functional programming techniques using Perl 5 such as higher order functions, recursion, memoizing, dispatching, lazy evaluation, etc. :)

Vim is my favourite editor (and IDE) for programming, editing, writing etc. Vim is like Perl: You always find something new how do do things. I think this is amazing! I found a small advanced Introduction to Vim in the internet. The following commands I didn't know until now: gs ga gf gD :later :earlier :mkview :loadview :bufdo . It's worth reading it, because it's not so much to read and it should contain a few tricks you don't know already :)

Yet another small website of mine is use.perl9.org. It's a collection of small Perl 5 code snipplets. It also contains Perl fun stuff and Perl Poetry. Here is one of my favourite Poems I wrote:

#!/usr/bin/perl

# (C) 2006 by Paul C. Buetow (http://paul.buetow.org)

goto library for study $math;
BEGIN { s/earching/ books/
and read $them, $at, $the } library:

our $topics, cos and tan,
require strict; import { of, tied $patience };

do { int'egrate'; sub trade; };
do { exp'onentize' and abs'olutize' };
study and study and study and study;

foreach $topic ({of, math}) {
you, m/ay /go, to, limits }

do { not qw/erk / unless $success
and m/ove /o;$n and study };

do { int'egrate'; sub trade; };
do { exp'onentize' and abs'olutize' };
study and study and study and study;

grep /all/, exp'onents' and cos'inuses';
/seek results/ for @all, log'4rithms';

'you' =~ m/ay /go, not home
unless each %book ne#ars
$completion;

do { int'egrate'; sub trade; };
do { exp'onentize' and abs'olutize' };

#at
home: //ig,'nore', time and sleep $very =~ s/tr/on/g;
__END__

Here is a prove, that Perl is better than Python! The prove proves, that you can program in Perl without using a semicolon as well. You don't have to use Python in order to do so! So Perl is at least as good as Python or even better! (don't take it too serious :)