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.
The isNaN() function (NaN stands for Not a Number) can be useful if you are looking at form inputs or similar and is used to detect if a value is not a number. For example, the following code shows the output of isNaN() on two variables.
Sometimes, especially when moving data from one server to another, you might find that you have encoded your MySQL database incorrectly. This problem with first show itself if you have the database encoded in one charset and your website set to display in another. If this is the case then you will find strange characters appearing in your text, especially when using punctuation marks. If you are unable or unwilling to change the character encoding on the site then you need to change how the data is encoded in the database.
Use the following snippet to convert any jpeg image into the equivalent image in ASCII format. It works by loading an image using the PHP GD2 library function ImageCreateFromJpeg() and then figures out the height and width of it. It then uses these values to loop through every pixel in the image and figures out the colour of that pixel. It uses this value to create a <span> element that uses the text colour of a # to change the colour of the text.
I have already talked about converting a sitemap.xml file into a urllist.txt file, but what if you want to create a HTML sitemap? If you have a sitemap.xml file then you can use this to spider your site, scrape the contents of each page and populate the HTML file with this information.
If you create a script that produces a sitemap.xml file there is no point in adapting this script so that it creates a urllist.txt file. The best solution is to use this sitemap.xml file to create the urllist.txt. The following script will do exactly this.