Matthew Daly's Blog

I'm a web developer in Norfolk. This is my blog...

30th March 2011 8:34 pm

New Phone

On Friday of last week I unexpectedly got a text from Vodafone saying I was able to upgrade my phone early. I was pretty pleased about this as having been something of an Android early adopter, I was still using an early Android phone, namely my HTC Magic. While a fine phone when it was released, it was only the second Android phone to become available in the UK and was therefore a bit dated compared to newer devices. It has been upgraded to Froyo (albeit a cut-down custom build) but that did slow the phone down somewhat.

So as soon as I had the opportunity I had a good look around for a new one to replace it. Right from the start I had my eye on the HTC Desire Z. Much as I love touchscreen phones, it’s very often extremely handy to have a physical keyboard, and as I’ve found myself using ConnectBot to connect to my home server via SSH a lot, the keyboard-toting Desire Z immediately had an advantage over the touchscreen-only models. Ideally I didn’t want to change my plan, so I checked out the deals for HTC phones on the same plan, and the Desire Z happened to be the only one on the same plan, so it was a no-brainer.

I got the phone on Monday, and it is amazing. The keyboard is easy to use and works well, the phone is lightning fast, and the UI is spot-on - it has everything I love about Android on the Magic (like the great notification system) and more. In particular I love the RSS reader- it syncs with Google Reader, so if I have to wait for a train, I can at least read some feeds while I’m waiting.

One thing I’m hoping to get more use out of is SL4A. I had this on my Magic, but coding on a touchscreen phone is not easy! I’m hoping that with the Desire Z’s keyboard, this will be a lot more useful.

21st February 2011 10:26 pm

More on My Mini Server

While I was very pleased to get a proper Linux distro working on my Pogoplug, the Arch-based Plugbox Linux was never really my cup of tea. While it’s a fine distro, I always felt that Debian would have been a much better fit. Partly this is because Debian has established a strong history of being a solid, stable distro that would carry on working no matter what, whereas Arch is more bleeding-edge. Also, Debian has a colossal repository that included a lot of software I wanted that wasn’t in the Arch repositories and I couldn’t get to install or compile from source, such as procmail and Squirrelmail. Debian also has strong support for many different processor architectures, including armel. Finally, being an Ubuntu user on the desktop, Debian is a distro that feels much more familiar to me.

So I eventually gave up on running Plugbox Linux and took the opportunity of the release of Debian Squeeze to install it on my Pogoplug, thanks to this tutorial. With that done, I set about adding my favourite applications. Byobu is a really handy tool that makes GNU screen significantly more intuitive and useful, so that’s always one of the first things to go on, and one that I’d really missed in Plugbox. I’ve now gotten my mail server working again, with the addition of procmail as my mail filter and Squirrelmail to give me a web interface. I’ve also set up Leafnode on there as I’d really like to learn more about Usenet, and I’m beginning to get the hang of using slrn to read it.

It’s amazing how much running my own server has taught me about security. I was staggered to see the sheer number of attempts by script kiddies to connect via SSH to my Pogoplug, and it really made me start thinking about security in a way I’d never bothered beforehand. I’ve installed denyhosts to block atttempts to brute-force the password, and made sure I chose a good password. I’ve also set OpenSSH to listen on a different port, which should hopefully decrease the number of login attempts substantially (I presume most of these were just script kiddies scanning large blocks of IP addresses looking for hosts with port 22 open), and have disabled root login (as at right now my login is the only one that is allowed via SSH, so if anyone does bother to do a more thorough scan and try to connect to the port I’m running SSH on, they’ll need to guess my username AND password, and do so before denyhosts kicks them off - a pretty tall order).

The whole concept of “plug servers” is one I really like, and my experience with the Pogoplug has been extremely good - it’s an inexpensive and extremely hackable device that has been an absolute pleasure to use.

24th January 2011 12:30 am

My New Mini Server

For a while now I’ve wanted a home server of some description, the idea being that it was something I could use to run a web server for development purposes, and a mail server so I could have an offline backup for my Gmail account (considering how much I rely on it, it’s only prudent to plan for what might happen if Gmail went down), and whatever else I need. Also, I only have laptops at present so I liked the idea of having something I could leave on all the time and connect to remotely via SSH.

Around Christmas, I read a forum post by someone who’d bought a PogoPlug cheap from PC World and had hacked it into a web server using Plugbox Linux, an Arch-based Linux distro. Shortly afterwards, I went into a branch of Currys in Norwich, and they had one on sale (£20 off the RRP of £70), so I shelled out for it. I already had a load of USB flash drives lying around, and an 8GB one is big enough for what I had in mind. After all, I wasn’t going to be serving anything that demanding over it, so something small and low-powered should be fine.

This weekend I finally got round to getting it set up. The PogoPlug service is actually pretty good - if you’re unfamiliar with it, it’s basically a self-hosted version of Dropbox, where you buy the device, connect it to your router, attach up to 4 flash drives or hard drives via USB, then share the files stored on them easily across your home network or over the Internet. However, this wasn’t really what I wanted.

Installing Plugbox Linux wasn’t hard - I merely had to activate SSH from the PogoPlug’s control panel, connect and kill the hbwd process, then install a new bootloader to enable it to boot the new OS. Once that was done, it was a case of attaching a flash drive, ensuring it was correctly mounted and the filesystem was set up properly, then downloading the Plugbox Linux tarball and unpacking it on the flash drive, before rebooting into the new OS.

Once it was installed, it wasn’t too hard to get the hang of pacman. I’d prefer it to have been Debian-based as that’s what I’m most familiar with, but that’s just personal preference. After a little tinkering I now have Postfix and Dovecot working on there, as well as Apache (although it might make sense to switch to something lighter, such as lighttpd or Cherokee). I’ve given it a fully qualified domain name via a free subdomain at dyndns.org, and I can now access emails on there via IMAP. Outgoing email works fine too, so I can always set up a Perl script or two to notify me if anything goes wrong by sending an email to my Gmail account. I’ve set up fetchmail to pull emails from my Gmail account via POP3, so all my email is in the process of being backed up on there, and I can use my phone to access it via IMAP, or SSH in and read it with Mutt. Going forwards, I may install Squirrelmail as well to give me more options.

One thing I’m not too sure about - I couldn’t get incoming mails to work, and I’m unsure whether this is because it’s using a subdomain (the email address is basically matthew@mydomainname.dyndns.org) or Postfix is merely misconfigured. Is it possible to receive emails to a subdomain in this fashion?

Anyway, this is a really great little machine and it’s been lots of fun getting it set up. I have to say, though, I’m really disappointed with the range of home server and NAS products currently on the market. Most of the NAS systems offer very little in the way of functionality or customisability, and most of the home servers are a bit too big, powerful and expensive, and usually run Windows Home Server, which isn’t really my cup of tea.

What I’d like to see is a small home server with a couple of hard drive bays at most, and a Debian or Ubuntu-based OS with access to apt-get and tasksel, so it’s easy to install whatever you want from the repositories. Also, give it a web interface that’s simpler than Webmin and makes it quick and easy to set up common software, but offer an advanced option for those that want it. That would be a fantastic device for end users - if it made it easy to set up a UPnP server, a Firefly server, or a BitTorrent client, that would be really useful.

13th November 2010 8:20 pm

A Slight Change...

Just to say I’ve changed the contact form I use on here. I always wanted to use one with a built-in CAPTCHA facility, as Disqus seems to have pretty much killed off the comment spam, but I was still getting it via the contact form. I’ve put off doing something about it till now, but it was getting out of hand so I’ve gone and found a new contact form. Let’s hope this kills the spam…

29th October 2010 8:49 pm

Deleting Unwanted Vim Swap Files Using Perl

Yesterday I realised that I had somehow managed to scatter Vim swap files all across the Dropbox folder I use to share Perl and Python scripts I’d written between several computers, and it would be a good idea to clear them up. I didn’t like the idea of using grep to search for them and manually deleting them, so I decided this was the ideal opportunity to write a Perl script to do it for me!

I came up with the following:

#!/usr/bin/perl -w
use strict;
use Cwd;
sub searchDir
{
# Subroutine to scan a directory looking for Vim swap files
# Get directory to read and current directory
my $readdir = shift;
my $startdir = cwd();
# Change directory to the target one
chdir($readdir) or die "Unable to open $readdir! $!\n";
print "Scanning contents of directory $startdir\n";
# Open the directory and grab the names of all the files and folders in it
opendir(DIR, ".") or die "Unable to open current directory! $!\n";
my @entries = readdir(DIR) or die "Unable to read directory! $!\n";
closedir(DIR);
# Loop through the files and folders in the directory
foreach my $entry (@entries)
{
# Skip this one and the one above it in the filesystem hierarchy
next if($entry eq ".");
next if($entry eq "..");
# If a file is a directory, call the searchDir subroutine recursively in order to scan it
if(-d $entry)
{
searchDir($entry);
next;
}
# Use a regular expression to check to see if the current file starts with a period, and ends with .swp - if it does, it's a Vim swap file
if($entry =~ m/^\..*\.swp$/)
{
# Inform the user that a Vim swap file has been found and print out the path to it
print "Found a Vim swap file!\n";
my $swppath = cwd();
print "It's the file $entry in $swppath.\n";
my $fullpath = $swppath . "/" . $entry;
print "The full path is $fullpath.\n";
# Prompt the user to delete the file
print "Do you wish to delete this file? (Y/N)\t";
chomp(my $reply = );
if($reply =~ m/y/i)
{
print "Deleting $fullpath...\n";
unlink($fullpath);
}
}
}
chdir($startdir);
}
# Get directory to begin the search
print "Enter directory to start search: ";
chomp(my $beginSearch = );
# call searchDir to start the search
searchDir($beginSearch);

Thankfully, I’ve now discovered the Preserve Code Formatting plugin for WordPress, which seems to do a good job at making the code look presentable!

This isn’t perfect - it uses recursion to examine subdirectories, and when I ran it on my /home folder it somehow wound up in /sys on my Ubuntu machine and I ended up getting a deep recursion warning (a little research suggests this happens when it goes over 100 directories in). However, it seems to work fine for scanning individual folders in my /home directory, and that’s all I really wanted anyway.

I love how Perl makes writing this kind of simple script so easy. It’s a great language for that kind of systems administration task.

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About me

I'm a web and mobile app developer based in Norfolk. My skillset includes Python, PHP and Javascript, and I have extensive experience working with CodeIgniter, Laravel, Django, Phonegap and Angular.js.