Quickies, by Andrea Olivato

Update DynDns host with current IP with Perl

Updates any DynDns host with current IP address. Useful if put in crontab and executed every 15mins.

#!/usr/bin/perl

# Load Needed Modules
use strict;
use XML::Simple;
use LWP::UserAgent;

# Get login data
my $username="DynDns_user";
my $password="DynDns_user";
my $hostname="yourhost.example.com";

# Create a new useragent
my $ua = new LWP::UserAgent;
$ua->agent('Mozilla/5.0 (X11; ; Linux i686; it; rv:1.9.1) Gecko/20090701');

# Create and perform a request to get current IP address
my $req = new HTTP::Request GET => "http://ip-address.domaintools.com/myip.xml";
my $content = $ua->request($req)->content();

# Create XML class and parse results
my $xml = new XML::Simple (KeyAttr=>[]);
my $data = $xml->XMLin($content);

# Get my current ip address from xml tree
my $ip = $data->{ip_address};
my $old;

# Open script log and read old ip address
open (MYFILE, '/tmp/ip-ch.log');
$old = ;
close (MYFILE);

# Open script log and write new ip address
open (MYFILE, '>/tmp/ip-ch.log');
print MYFILE $ip;
close (MYFILE);

# If new ip is different from previous one
if ($old != $ip) {

        # Create a new useragent
        my $ua = new LWP::UserAgent;
        $ua->agent('Mozilla/5.0 (X11; ; Linux i686; it; rv:1.9.1) Gecko/20090701');

        # Create and perform a request to update hostname associated ip
        my $req = new HTTP::Request GET => 'http://'.$username.':'.$password.'@members.dyndns.org/nic/update?hostname='.$hostname.'&myip='.$ip.'&wildcard=NOCHG&mx=NOCHG&backmx=NOCHG';
        $ua->request($req)->content();
}
 

Urlencode a string in #perl

Quick script able to urlencode a string without the needing of importing modules

$mystring = "String to encode";
$mystring =~ s/([\W])/"%" . uc(sprintf("%2.2x",ord($1)))/eg;
print $mystring;
# Returns String%20to%20encode

Check if variable is an array in #perl

This is quite useful when parsing xml code and you don’t know if an object contains an array of tags or a single value.

eval {
	$#{$isthisanarray}
};
if ($@){
	print "Nuuu! It's not";
} else {
	print "Yes it is";
}

Perl and Sqlite3 quick start example guide

1. Set up your sqlite database file

sqlite3 demo.db
SQLite version 3.6.13
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite>
create table datas (
        id integer,
        name text,
        date text
);

2. Execute simple operations with perl

#!/usr/bin/perl

# Import needed Modules
use DBI;
use strict;

# Connection to DB file created before
my $dbh = DBI->connect("dbi:SQLite:dbname=demo.db","","",$dbargs);

# Two simple insert Queries 
# I use ->do as I don't need to do anything with returned obj
$dbh->do("insert into `datas` (id, name,date) values (1,'something','1986-06-07')");
$dbh->do("insert into `datas` (id, name,date) values (2,'otherthing','2009-03-02')");

# A simple select statement
my $query = "SELECT * FROM datas ORDER BY id DESC";
my $query_handle = $dbh->prepare($query);
$query_handle->execute();

# Instead of simply fetching rows I prefer, for each one,
# to assign values to predefinite values.
# Bind columns is a wonderful function!
$query_handle->bind_columns(\my($id, $name, $date));
while($query_handle->fetch()) {
   print "$id, $name, $date \n"
}

# Close connection
$query_handle->finish;
undef($dbh);

Encrypt & Decrypt strings in #Perl using Tea

Simple two way encrypt/decrypt script in Perl using Tea Algorithm. Light and fast as hell

#!/usr/bin/perl

use Crypt::Tea;
my $string = 'tobecrypted';
my $key = 'somekey';

# Print Original String
print $string."\n";

# Encrypt the string using my key
$user = encrypt($string,$key);

# Print Encrypted String
print $string."\n";

# Decrypt the string
$user = decrypt($string,$key);

# Print back Original String
print $string."\n";

How to switch 2 $vars value in #Perl

How to simply switch two variables values in Perl.

#!/usr/bin/perl

# Assigning 2 vars
my $some = "some";
my $thing = "thing";

# Switching them
($some, $thing) = ($thing, $some);

# See what happened
print '$some is now "'.$some.'"';
print "\n";
print '$thing is now "'.$thing.'"';

Dump variables in Perl

How to show content of unknown objects in perl using Dumper

use Data::Dumper;
print Dumper $my_unknown_object;

Find & replace multiple files with Perl

How to search and replace a string within some files with perl, launched from a shell.

# I'm looking for 'some' in all my .js files
# and I want to replace it with 'foo'
perl -pi -w -e 's/some/foo/g;' *.js

Creating a Twitter @reply from Perl

How to update your twitter account using Perl, specifying an ‘in reply to’ parameter.

#! /usr/bin/perl

# Configuration
my $TW_USER = "USERNAME";
my $TW_PASS = "PASSWORD";
my $INREPLYTO = "POST_ID"; # Retrieve this from Twitter
my $MESSAGE = "SOMETHING TO SAY";

# Import library and get an User Agent
use LWP::UserAgent;
my $ua = new LWP::UserAgent;

# Set up the request
my $req = new HTTP::Request POST => 'http://twitter.com/statuses/update.xml';

# Authenticating and setting up post data
$req->authorization_basic($TW_USER, $TW_PASS);
$req->content("status=$MESSAGE&in_reply_to_status_id=$INREPLYTO");

# Send the request
my $res = $ua->request($req);

# print $res->status_line; # Uncomment this for debugging