What is an Application Programming Interface?
An Application Programming Interface, shortened for API, is a set of methods and functions as part of a framework or library in order to perform certain functions within an application that makes use of the Application Programming Interface. An example of an API is the PHP PEAR (PHP Extension and Application Repository) library, which provides an entire library of classes and their methods for:
- Authentication and Security
- File System
And much more.
Other frameworks include the .NET framework which is primarily used for the creation of Windows application and server-side ASP.NET web applications. However, ASP.NET applications only run on the Windows Hosting platform.
What are the primary advantages to making use of an Application Programming Interface?
An Application Programming Interface provides a common and an easy-to-use interface for creating an application and working with:
- An operating system.
- An application programming framework or library.
For example, part of an API may be functions in which to construct a Graphical User Interface for an application. For example, if you’re using PHP-GTK for creating a graphical user interface, you would use several methods in the Application Programming Interface:
- GtkWindow – This is to create a graphical window.
- GtkButton – This is to create a button and in most cases to add to the GtkWindow to make it visible.
- GtkTextView – For displaying a text box on your GtkWindow.
- GtkVBox – This is to display multiple widgets on a GtkWindow. A GtkWindow can only display one widget at a time, and so you’d add a GtkVBox to be able to add both a GtkButton and GtkTextView onto the same GtkWindow instance. You can also use GtkVBox’s and GtkHBox’s to centre certain widgets on a GtkWindow or to position them to the left or to the right.
In the .NET framework, you can add a button widget onto your window (or “form”, as it is called in the .NET framework) using the Button class in the .NET franework – specifically located in the Systems.Windows.Forms namespace (a namespace is essentially to separate different segments of a library and is extensively used in the .NET framework).
Essentially, an Application Programming Interface is an interface for programmers to make use of to make it easy to interface with the breadth of features and functionality developers can use, for example, when developing applications for Windows or OS X. In OS X, the API developers use for developing applications is primary Cocoa.