I was looking at some malfunctioning code the other day where the price was pulled out of one API service and sent to another API. The problem stemmed from the fact that the value coming out of the first API was as a string and the second API required the price in pence as an integer.
The difference in formats here meant that the number had to be converted from one format to another. During this process it was found that the value was sometimes out by a single pence.
If you create classes in PHP then you should be unit testing them as much as you can. Setting up unit testing classes for your code can be time consuming and involve a bunch of copying and pasting. Thankfully, PHPUnit comes with a couple of helper functions that allow the creation of unit testing classes automatically, which can save a bit of copying and pasting.
As an example for this post I will use the following Spider class, which is part of some code I am working on at the moment to create a simple site spider in PHP.
The instanceof operator is used in PHP to find out if an object is an instantiated instance of a class. It's quite easy to use and works in the same sort of way as other operators. This can be useful to controlling objects in large applications as you can make sure that a parameter is a particular instance of an object before using it. Lets create a couple of classes as examples.
When validating a password it is easy enough to make sure that the password is of a certain length, but what happens if you want to make sure that the password has at least one number, or contains a mixture of upper and lowercase letters? I recently had to validate a password like this and so I created a password validation class that allows easy validation of a password string to a set of given parameters, but also allow these parameters to be changed when needed.
The is.gd URL shortening service is yet another site that converts a long URL into a small one, but is.gd differs in that it generally produces smaller URLs than others. The is.gd API doesn't require that you create an account on the site, but there are one or two limitations to using the service that you should be aware of first. You can find out these limitations by reading the is.gd terms and conditions.
There are a few URL shortening services about, of which bit.ly is just one. However, it does provide a nice API for developers to interact with the site. Not only is it possible to shorten URL's, you can also reverse them, find out information about the site and get information about how many people have used to link. The API requires you to create an account to interact with the API. Once you have created an account you can use the API service.
What? Don't worry, I can't say it either. It is officially called the Scope Resolution Operator (but also just a double colon) and is used to reference static properties and functions of a class. It is also used to reference overridden functions of classes.
To reference a constant of a class you do something similar to the following.