<?php $unique_identifier = md5(rand(100000, 999999)); ?>

The problem with this is that I have given an allowance for only 899,999 possible values. I didn’t realize my error until I started getting mysql integrity check errors for a unique column that stored that value.

I reverted to using a more elegant solution:

<?php $unique_identifier = md5(uniqid(rand(), true)); ?>

The uniqid statement generates a globally unique identifier with a rand() prefix and using much more entropy (true).

So I went about contacting some of my colleagues who gave me pointers on whom to see and after making a few contacts, I was well on my way to organizing the seminar.

I got a lot of support there and we were able to get about a hundred diploma students at the University of Jos to attend. I was initially thinking about organizing something strictly for web developers and programmers. I had a few ideas about web-based APIs, mashups, code versioning, improving web application performance, etc. but when I was told the caliber of people who were going to be attending the seminar, I decided to stick to something regular computing students will be interested in.

I gave a presentation on Web APIs and Mashups and after the short slideshow, went into building a practical mashup. I was a little concerned about making sure I didn’t speak over the top of their heads and so looked for something very practical to demonstrate a mashup. I ended up building an application that sent a text message to their mobile phones. Afterwards, I went on to talk about the various freely available APIs on the web that can be used to build smart applications and encouraged them to try them out.

There were only a very few individuals there who had done anything for the web but based on the inquiries I received at the end of the seminar, I knew a lot of them had gotten very interested in making further exploration.

I ended the seminar by talking about web mapping and most especially Google Mapmaker and told them about how Plateau State had very little content on the Internet and how that was an opportunity to do something. I’m told that there are plans to build a team that will take what they’ve learnt from the seminar and do something about it.

The success of the event was more than I envisaged and I’m encouraged to give many of these talks and presentations in other parts of the country.

Essentially, hooks allow you to execute custom scripts when you perform certain actions on your repository like committing files, pulling updates and so on. This is a very useful as you can write hook scripts to (say for example) automatically ftp a file to your web server when a change has been made.

A whole lot of really cool hook scripts have been written and if you use any code versioning tools, you should check out the ones that have been written for the tool you use.

In particular, I find that sometimes developers could check in code that has syntactic bugs. This happens in environments where there are no strict code testing rules. It can be really annoying when you or someone else does this and you have to fix that and then commit again… not professional at all. So I came across this post by Travis Swicegood that lists code that does a php lint on your PHP files before committing them to the repository. PHP lint (php -l) basically checks the syntax of your code and either gives an “ok” or prints the offending line.

For one of the projects I’m working on, I had to change line 11 of Travis’ code to read:

$filename_pattern = '/\.(php|engine|theme|install|inc|module|test)$/';

instead of

$filename_pattern = '/\.php$/';

If you’ve done Drupal coding, you’ll quickly recognize that

There was really no point in scratching my head and trying to pull my hair out in order to fix this. So I googled a solution. This post gave me a hint but wasn’t helpful enough so I decided to write a blog post on how to go about solving this.

You’ll have to configure your repository in your .ssh/config file. Here’s an example. Simply substitute the #*# placeholders for the actual values

Host #hostname#
  User #username#
  Hostname #hostname#
  Port #non-standard port#

And if you prefer to use private keys to login:

Host #hostname#
  User #username#
  Hostname #hostname#
  Port #non-standard port#
  PreferredAuthentications publickey
  IdentityFile "#path_to_private_key#"

Earlier today, I wrote a new post on this blog and having ignored the blog for a while, I noticed that there was a new upgrade for WordPress (the software that powers this blog) and I thought – “Hey why don’t I do some site maintenance in the process.” and there I went to click on upgrade automatically. I (like I usually do) ignored the advice to backup the site before upgrading and just clicked through. For some reason (I thought my Internet connection broke) the process didn’t display a success status but I assumed it went well.

Thanks for my friend Tunde Adeyemi (@barbietunnie) who pointed out the fact that the site was broken and needed fixing. I quickly replaced the site with a “We’ll be back soon” banner page and went about fixing it. Thankfully, nothing was damaged and the process took less than 30 minutes. So next time you want to do upgrades (especially when it involves the core), do take the advice you’re given.

Victoria Island roadmap as appeared on Google Maps on 22 March, 2009

I dabbled into Google Maps mashups and built my first Google Maps application when I was working on my final year project in the University but then I saw little use for it locally.

A few months back, Google announced a community-based mapping project known as Google Map Maker. Google Map Maker enables the people who live in areas that have not been well covered by Google to map their localities using the tools that Google has provided. The implication of this is that you now have the ability to map your village, if you wanted to.

Google Map Maker tile of Victoria Island as at March 22, 2009

What’s the motivation?

That’s a rather interesting question because I never really gave thought to it when I started creating maps using Google Map Maker but in giving thought to it, I realized that in providing local content on the Internet not only does it makes the Internet richer but it also provides value for the locals. I earlier mentioned how the Mapping service was of little use to me because there wasn’t local data but now, with other people mapping different areas within the country, I am able to determine routes before setting out (for instance).

I remember a particular day I was to meet up with someone somewhere in Lagos Mainland. He described the point of meeting as around the intersection of Opebi Link Road. I wasn’t sure of the location but then I thought “worst case scenario, I’ll ask someone about it.” I decided to put Google Map Maker to the test. I did a search for Opebi Link Road and voila, it showed me the location and I was able to know where it was and how to get there.

Imagine then that you are looking for the nearest branch of a particular bank. Apart from having to consult the list of branches from the bank’s web site, you can look it up on Google Map Maker. Now eventually, the information will be integrated into Google Maps proper but for now, everything is still available on Google Map Maker.

So what happens if the information you are looking for is not available? Add it! There’s no reason why your company’s branches or building (or other features like street names, restaurants, churches, mosques, entertainment venues, etc) is not tagged on the map. Information is being added to the map on a daily basis and your contributions are not only helping give your company visibility, but it’s also adding value to others who might find that information useful when the need arises.

Loy Okezie recently published a blog post listing a few of what he thinks to be the top 100 web developers in Nigeria. I found the comments to be very educative and interesting.

I happen to know virtually everyone on that list and while some comments on the site and elsewhere were such that the author was partial, there’s something very important here that I wish every other developer (that was nominated) will do something about – Get visible. The people on that list were there because Loy happened to know about them. Loy hasn’t met a number of them physically but using online interaction tools and social networks, he’s been able to get to know them.

After reading the comments on the blog and the discussion forum, I was happy to know that there are people making a difference all over Nigeria but they need to get visible and let the whole world know what they’re doing. At the very least, I expect these web developers to have a Twitter account (since I refer to it as a blog for lazy bloggers) and better still a blog. If they are very ambitious, they can go ahead to have a proper web site with profiles of what they’ve done, a blog and so on.

Here are certain assumptions:

1. You are using Windows XP or Vista as your local machine.
2. You have a Linux/UNIX host as your remote machine.
3. You are using the Apache web server on both machines.
4. You have basic Linux/UNIX administration skills.
5. You’re comfortable with basic level Apache configuration and know what .htaccess is.

Step 1

First of all, we will be using a technique known as SSH port forwarding. This makes it possible to have an SSH server that has a public routable address (public IP) to forward an arbitrary port number to our local machine. For this demonstration, I chose to forward port 8080 on the remote machine to port 80 on my local machine.

SSH servers by default are now being configured in such a way that this forwarded port is only accessible from within the remote machine (AKA localhost). In order to ensure that this forwarded port is accessible to any machine connecting from the Internet, you need to tweak the settings of the SSH server running on the remote machine.

Simply edit the /etc/ssh/sshd_config (the path may be different) file on the remote machine and comment out the line GatewayPorts no. Change the value from no to yes. Save the file and reload the SSH server.

Step 2

Next on your local machine, you will need to create the SSH tunnel to the remote machine. This can easily be done using the plink application in the PuTTY suite of applications. Please visit http://www.chiark.greenend.org.uk/~sgtatham/putty/

Simply launch the plink application from your command prompt using the following syntax:


plink -R %REMOTE_PORT%:%LOCAL_IP%:80 %USERNAME%@%SERVER_ADDR%


%REMOTE_PORT% is the remote port you wish to forward. In my case it was 8080.
%LOCAL_IP% is your local machine’s IP address. In my case, I simply used the localhost IP – 127.0.0.1
%USERNAME% is your username on the remote machine and %SERVER_ADDR% is either the IP address or hostname of the remote machine.

Once you’ve logged in, the port on the remote machine is forwarded to your machine. If your web server is running on a port different from 80, change the syntax accordingly.

You can test connectivity by going to http://%SERVER_ADDR%:%REMOTE_PORT%/. This should display contents from your local web server. If you wish to simply use this, you’re fine but if you want something cleaner and more invisible, then you’ll want to proceed.

Step 3

Next step is configuring your hosting account (a subdomain will be best) to proxy requests to your local machine’s web server.

Create your subdomain and navigate to the document_root of that subdomain. Edit/create a .htaccess file and put the following into it.


RewriteEngine on
RewriteRule ^(.*)$ "http://%DOMAIN%:%REMOTE_PORT%/$1" [P,L]


Here, %DOMAIN% is either localhost or your domain/subdomain (which of course should have previously been configured to point to the remote machine), %REMOTE_PORT% is the remote port configured on the remote machine. The magic being performed here is done by the [P,L] directive that proxies any requests to the local machine through the tunnel accessible from the remote port. The $1 parameter passes on any url parameters to the local web server.

Once this has been completed, visiting http://%DOMAIN%/ will bring up content from your local machine. This is made possible by virtue of the proxy features in the Apache web server.

Step 4

This final step is only needed if you intend to be able to log the original ip address the request came from before the proxying was done.

This involves modifying your local machine’s web server configuration.

Simply locate the VirtualHost or main configuration section in the Apache configuration file and add this:


LogFormat "%{X-Forwarded-For}i %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" proxylog
CustomLog logs/custom-access.log proxylog


This directive is a modified combinedlogs directive to use the HTTP_X_FORWARDED_FOR header parameter instead of the IP address in logging the request.

Save the file and reload/restart your web server.