PHP

Different functions and options are always being added to PHP. Although new versions generally don't create much backward compatibility issues it is usually prudent to write production code that you know will work on servers running a slightly older version of the language.

To check the currently used PHP version you can use the function phpversion() or the constant PHP_VERSION. Both the function and the constant return a string that contains the version number. There are a couple of ways in which this information can be used, the first is to take the string and convert into an array using the explode() function. With this array you can then check the minor version number and run code like the following:

If you need to know the month from a given integer (from 1 to 12) then you can use the following snippet. This will return the string "Feb".

This can be encapsulated into a function call that will take a number between 1 and 12 and return the corresponding string for that month. This function includes some simple error checking to make sure that the number is valid before trying to work out the date.

Removing the last line from a file is an easy process and can be done in just a few lines of code.

XML data extraction can be a common task, but to work directly with this data you need to understand how PHP parses XML. There are various different functions involved in parsing XML in PHP, all of which work together to extract data from a XML document. I will go through each of these functions and tie them together at the end.

xml_parser_create()

This function is used to create the parser object that will be used by the rest of the process. This object is used to store data and configuration options and is passed to each of the functions involved.

If you want to create a "rounded" time stamp, for example, to the nearest 15 minutes use this as a reference:

Converting an IP address into some useful location information can be useful if you want to find out where sites are hosted or customise content to users depending on their location.

All this code is freely available over at github.

There are several ways to do this, all of which have their advantages and disadvantages, but sticking with one can cause rewriting a lot of code in the future. So rather than pick one and stick with it I decided to use dependency injection to allow different classes to be used that convert IP addresses to locations in different ways. The first task is to create an abstract class that will be used to construct the rest of the IP location classes. Each class that extends this abstract class will contain a method called getIpLocation() that will convert an IP address into a location, and a method that will update the data source for the location lookup. Rather than lump all of the classes into a single directory I have created a directory called Service, into which all of the different classes that lookup IP addresses will be kept.

Using file_get_contents() to fetch the contents of a file is quite a common practice. This might be just to get the contents of a text file or to get the ImageCache module in Drupal to pre-cache images. The file_get_contents() function can get a local or remote file and is usually run like this.

However, when trying to use this function to communicate with an authenticated server you will see the following error appearing.

When creating functions in PHP it is possible to provide default parameters so that when a parameter is not passed to the function it is still available within the function with a pre-defined value. These default values can also be called optional parameters because they don't need to be passed to the function. I have seen this sort of code being used incorrectly quite often recently so I thought I would go over it in a post.

Creating a default parameter in a function is very simple and is quite like normal variable assignment. The following function has a single parameter that is set to 1 if it is not passed when calling the function.

function testFunction($a = 1)
{
    return $a;
}

Overloading in PHP describes the way in which properties and methods of an object can be dynamically created or accessed without having to define them first. Traditionally, the word overloading in programming is used to describe accessing object methods with the same name but with different parameters. It is not possible to do this in PHP as it will complain about methods having the same name, so the term describes calling a method or accessing a property that hasn't previously been set or is out of scope. In object orientated terms this means that the method or property is private.

Object Property Overloading

Property overloading allows you to access the property of an object through a method without having to write them first. It can also be used to access any properties that are inaccessible. There are two basic property overloading methods available, these are __set() and __get(), both contain a double underscore (_) in their name.

I'm not sure where I found this, but I have been using it on a few projects recently and it's helped a lot. It basically detects what system you are on and will give you a constant that keeps hold of the slash for that system.