PHP

Net_Ping is a PHP wrapper for the ping program and provides a neat way pinging a host or checking if a site is up and running. To install it you just need to have pear installed. Once that is done you can do a search for PEAR Net_Ping by opening a terminal and typing:

> ping search ping

This will return the following:

Retrieving data...0%.MATCHED PACKAGES, CHANNEL PEAR.PHP.NET:
=======================================
PACKAGE           STABLE/(LATEST) LOCAL
Net_Ping          2.4.4 (stable)        Execute ping
Services_Pingback 0.2.2 (alpha)         A Pingback User-Agent class.

You can install Net_Ping by running the following:

> pear install Net_Ping

Which should produce the following output.

If you have a site with parts of it using SSL, but want to turn it off for mundane pages like the blog section then use the following code. This uses the $_SERVER['HTTPS'] variable to see if HTTPS is turned on, if it is then a header is issued and the page redirected.

if ($_SERVER['HTTPS'] == 'on') {
    $url = "http://" . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    header('Location: ' . $url, true, 301);
    exit();
}

You can turn it back on again on your secure pages using the opposite.

if ($_SERVER['HTTPS'] != 'on') {
    $url = "https://" . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    header('Location: ' . $url, true, 301);
    exit();
}

Don't include both of these scripts on the same page or you will break the site! Also, make sure that no headers have been issued before hand as this code can cause a "headers already issued" error.

Converting an array of information into a string is easy, but when you are doing this for insertion into a database having trailing commas is going to mess up your SQL statements.

Take the following example, which takes an array of values and converts them into a string of values. This practice is quite common in PHP database manipulation.

$values = array('one', 'two', 'three', 'four', 'five');
$string = '';
 
foreach ( $values as $val ) {
    $string .= '"'.$val.'", ';
}
 
echo $string; // prints "one", "two", "three", "four", "five",

Obviously we need to strip the trailing comma from the end of this string. To do this you can use the following function.

A prime number is a number which has exactly two distinct number divisors: 1 and itself. So if you take the number 11, it can only be divided to get a whole number if it is divided by 1 or 11. If any other number is used then a fraction is always found.

The following function uses a method called trial division to detect if a number is prime or not.

PHP TestFest 2009 is a series of events that you can go to and learn how to test PHP and make new friends and contacts in the PHP community.

One thing that concerned me was that writing these tests might require a in depth knowledge of C++ but this is not the case. Each test is just writing a few lines of PHP code (preferably no more than 10) which will have a known outcome. The tests will be run and the output compared to the expected outcome. For more information about writing tests please refer to the phpt test basics page from the PHP site.

Disemvoweling is a technique used on blogs and forums to censor any post or comment that contains spam or other unwanted text. It involves simply removing the vowels from the text so that it is almost, but not entirely, unreadable.

Use the following function to disemvowel a string of text.

function disemvowel($string)
{
    return str_replace(array('a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U'), '', $string);
}

As an example, the first sentence on this post:

Disemvoweling is a technique used on blogs and forums to censor any post or comment that contains spam or other unwanted text.

would appear like this:

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.