PHP

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.

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.

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.

The following function will rename all of the image files in a directory to be sequential. The parameters are the path of the directory that the files are in and the name of a function that will be used to sort the array of files through the PHP usort() function.

function sequentialImages($path, $sort=false) {
 $i = 1;
 $files = glob($path."/{*.gif,*.jpg,*.jpeg,*.png}",GLOB_BRACE|GLOB_NOSORT);
 
 if ( $sort !== false ) {
  usort($files, $sort);
 }
 
 $count = count($files);
 foreach ( $files as $file ) {
  $newname = str_pad($i, strlen($count)+1, '0', STR_PAD_LEFT);
  $ext = substr(strrchr($file, '.'), 1);
  $newname = $path.'/'.$newname.'.'.$ext;
  if ( $file != $newname ) {
   rename($file, $newname);  
  }
  $i++;
 }
}

The following function can be used in the second parameter to sort the files by their last modified time.

Use the following function if you want to print the text in a particular colour, depending on what the background colour is.

function opposite($color) {
  $white = 0;
  for ($i = 0; $i < 6; $i += 2) {
    $white += base_convert(substr($color,$i,2),16,10) < 127 ? 1 : 0;
  }
  return $white <= 2 ? "000000" : "ffffff";
}

It works by looking at the colour and seeing how much of it is white. If greater than two parts are significantly white then the color returned is black, otherwise white is returned.

Here are some examples to test the function out.

This simple code example uses a combination of strrchr to find the last occurrence of a string and substr to return part of the string in order to find the file extension for a given filename. This is ideal if you want to quickly find a file extension.

$ext = substr(strrchr($fileName, '.'), 1);

This code can be used in the following way.

$fileName = '\path\to\file\afile.wibble';
$ext = substr(strrchr($fileName, '.'), 1);
echo $ext;

The output here is 'wibble';