Development

D-Link Wifi

The past few days I’ve been toying with Wifi equipment from D-Link – and access point (DWL-G700AP) and a wireless router (DI-524). These were pretty much the first to wifi-devices, which I’ve completely setup, and configured on my own, so it was an interesting experience. The first experience was in the weekend, when I tried to get a basic TDC Broadband (DSL) connection made avaiable wirelessly. Not knowing too much about Wifi, I though the Access Point was the thing to get, and the DWL-G700AP seemed to be a fair deal in the local IT-vendor. After spending a few hours trying to get it to work, I gave up and called a friend for some advice.

Basics on tables in Mysql

Navigating around in mysql is quite easy. You can see which databases by using the command “show databases”. There will always exist a database called “mysql” which is used by mysql itself.

If your user account has access to a database, you can access it by using the “use DATABASENAME” command. You can se which tables exist within a database by using the “show tables” command - and see details for each table by issuing the “desc TABLENAME” command.

Date calc with SQL

Micro tip of the day: How many days has past since a date field in the database?

SELECT (TO\_DAYS(NOW()) - TO\_DAYS(date\_field)) AS days\_past FROM tablename

Fetching available newsgroups from a news server

This script fetches a list of available newsgroups (and descriptions) from a news server. The group list is returned as a hashref where the keys are the groupname and the value is a description of the group. 

#!/usr/bin/perl -w
use strict;
use Net::NNTP;
use MIME::Base64 qw(decode\_base64);
use MIME::QuotedPrint qw(decode\_qp);

my  $server= "sunsite.auc.dk";
print STDERR "connecting to $server... ";
my $nntp= Net::NNTP->new($server);
unless($nntp) {
  print STDERR "failedn";
  exit 1;
}
print STDERR "okn";

print STDERR "getting messages... ";
my $newstuff= $nntp->newnews(time - 7\*24\*2600, "dk.edb.programmering.perl");
unless($newstuff) {
  print STDERR "failedn";
  exit 1;
}
print STDERR "okn";

my @messages;
foreach my $msgid (@$newstuff) {
  my $head= $nntp->head($msgid);
  next unless $head;

  my %msg;
  push @messages, %msg;
  foreach(@$head) {
    next unless /^(Newsgroups|Subject|From):s+(.+)$/i;
    $msg{lc $1}= $2;
  }
}

my $last= "";
foreach(sort { $a->{newsgroups} cmp $b->{newsgroups} } @messages) {
  if($\_->{newsgroups} ne $last) {
    print "n" if $last;
    $last= $\_->{newsgroups};
    print "$last:n";
  }
  print "t" . decode\_header($\_->{subject}) .
    " - " . decode\_header($\_->{from}) ."n";
}

sub decode\_header {
  my($text)= @\_;

  $text=~ s/=?(iso-?8859-.?|us-ascii|utf-8)?(q|b)?(\[^?\]\*)?=(s\*(?==?))?/&decode\_header\_block(lc $1,$2,$3);/gei;
  return $text;
}

sub decode\_header\_block {
  my ($input,$enc,$text) = @\_;
  if ($enc =~ /q/i) {
    $text=~ s/\_/ /g;
    $text= decode\_qp($text);
  } else {
    $text= decode\_base64($text);
  }
  return $text; # oh well  \[:-)\]
}

exit();

Fetching recent headlines from a news server

The followig piece connects to a news-server and fetches subjects from the last week in a specific newsgroup (the Danish perl-newsgroup) and prints these. 

#!/usr/bin/perl -w
use strict;
use Net::NNTP;
use MIME::Base64 qw(decode\_base64);
use MIME::QuotedPrint qw(decode\_qp);

my  $server= "sunsite.auc.dk";
print STDERR "connecting to $server... ";
my $nntp= Net::NNTP->new($server);
unless($nntp) {
  print STDERR "failedn";
  exit 1;
}
print STDERR "okn";

print STDERR "getting messages... ";
my $newstuff= $nntp->newnews(time - 7\*24\*2600, "dk.edb.programmering.perl");
unless($newstuff) {
  print STDERR "failedn";
  exit 1;
}
print STDERR "okn";

my @messages;
foreach my $msgid (@$newstuff) {
  my $head= $nntp->head($msgid);
  next unless $head;

  my %msg;
  push @messages, %msg;
  foreach(@$head) {
    next unless /^(Newsgroups|Subject|From):s+(.+)$/i;
    $msg{lc $1}= $2;
  }
}

my $last= "";
foreach(sort { $a->{newsgroups} cmp $b->{newsgroups} } @messages) {
  if($\_->{newsgroups} ne $last) {
    print "n" if $last;
    $last= $\_->{newsgroups};
    print "$last:n";
  }
  print "t" . decode\_header($\_->{subject}) .
    " - " . decode\_header($\_->{from}) ."n";
}

sub decode\_header {
  my($text)= @\_;

  $text=~ s/=?(iso-?8859-.?|us-ascii|utf-8)?(q|b)?(\[^?\]\*)?=(s\*(?==?))?/&decode\_header\_block(lc $1,$2,$3);/gei;
  return $text;
}

sub decode\_header\_block {
  my ($input,$enc,$text) = @\_;
  if ($enc =~ /q/i) {
    $text=~ s/\_/ /g;
    $text= decode\_qp($text);
  } else {
    $text= decode\_base64($text);
  }
  return $text; # oh well  \[:-)\]
}

exit();