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In any office there can be arguments about who will make the next round of tea. The following script will allow you to randomly pick a person who is going to make the tea. Rather than have a script that did this once and threw away the information I thought it would be a good idea to use cookies to save the form data for the next time you want to pick a person to make the tea. This is a good exercise if you are trying to understand how cookies work.

First, we will need to variables, the first is an array of people and the second is the number of people in the office.

$people = array();
$number = 10;

We can now build the form that will contain all of our names. Here we just cycle through a simple for loop and if an array item exists in the $people array for the value of $i then we use this in our form.

To format the current timestamp in W3C Datetime encoding (as used in sitemap.xml files) use the following parameters.

echo date('Y-m-dTH:i:sP', time());

As of PHP5 you can also use the c format character to print the exact same string.

echo date('c',time());

These would both print out the following:

2009-04-03T11:49:00+01:00

Whilst creating a site the other day I thought about how I would manage the sitemap.xml file. This file is basically a XML file containing a list of URLs. Most major search engines understand (and look for) this file, so having it present on a site is a definite must.

I have been down the route before of having a sitemap.xml file created by the application every time a new record or something was added, but as this was a high traffic, multi-user site this approach just had to many problems. The main problem (aside from the potential performance hit) was that I would have to spend hours tying the calls to the sitemap.xml creation file into my application.

The Zend_Cache class is part of the Zend Framework and is used (as its name suggests) to cache things. This can be anything from the front end browser output to the outcome of a complex calculation or even the results of database queries. Zend_Cache is an enormous topic, not just how the class works, but what the best practices are for caching.

The best place to start with caching is one of the simpler topics of caching database queries, from this point you can work on understanding other caching functionality. Normally, a call to a database table in Zend Framework might be done like this.

I talked a while ago about Adding Code To Wordpress Blogs And Comments, but I decided that it needed a bit of code to do this automatically.

So here it is, prepared by the text processor.

Getting started with SVN on Ubuntu takes only a few minutes, and enabling web access to the repository is also very straightforward.

First (in order to actually serve the files) you need to install Apache, open up a terminal window and run the following command. This will ensure that Apache is installed if you unselected it for some reason during the install.

sudo apt-get install apache2

Note the use of the sudo command. This will run the command you give it as a super user as normal users will not generally have access to install software like this. When you use sudo you will be prompted for the super user password. Next, use the following command to install SVN.

If you are familiar with PHP you will have come across the for loop at some point. When learning JavaScript it is important to remember that it also has the ability to do the equivalent of the PHP forloop.

The following snippet shows the creation of an array of things that can't be referenced by a normal for loop due to the odd numbering of the keys.

var arrThings= new Array();
 
arrThings[3] = 'thing 1';
arrThings[42] = 'thing 2';
arrThings[47] = 'thing 3';
arrThings[32] = 'thing 4';
 
var output = '';
 
for ( var thing in arrThings ) {
 output += arrThings[thing];
}

alert(output);

The variable thing is now the iterator and will iterate through each element of the array. By using this code you no longer have to include code that thinks about the length of the array.

A new feature in MySQL version 5.1.6 is the addition of events. These can be either a single event or a schedule, both of which can be given multiple commands to run.

First, you need to make sure that the event scheduler is running. To do this, open up MySQL query browser (or similar) and run the following MySQL command.

SHOW PROCESSLIST;

If the event scheduler you will see a row in the output that looks like this:

Id, User, Host, db, Command, Time, State, Info
120, 'event_scheduler', 'localhost', '', 'Daemon', 242, 'Waiting on empty queue', ''

Turning the event scheduler on and off is quite straightforward and can be done as a MySQL command, or as a parameter when starting the server, or even in an ini file. To turn the scheduler on as a MySQL command run the following:

There are three available cryptographic functions in PHP, these are md5(), sha1() and crc32(). All of the functions take a string and output a value that is encrypted and can't be reversed to the original string. In fact the only way to get the original string back is to run a brute force algorithm which tries to guess what the original string was.

To test these functions I will use the following string.

$string = 'wibble';

md5()

This function returns the hash as a 32-character hexadecimal number. The md5() function is used quite a bit and most PHP programmers will have come across it at some point.

Virtualization is basically a term used to describe the creation of a computer in software. The main benefits of which are that if you want to try out an operating system or test client server communications you don't have to get multiple computers. You can simply create a few computers virtually, which will act just like the real thing.

There are quite a few virtualization products available, some are free and some cost quite a bit of money. After messing about with quite a few different virtualisation products other the past few weeks I have uncovered a great bit of software called VirtualBox from Sun Microsystems.