As PHP has grown and matured, so have the tools for PHP developers. Integrated development environment choices have never been greater. One such IDE is the open source Eclipse Platform. Eclipse, essentially a rewrite of Visual Age for Java, was a donation to the open source community by IBM and quickly became a household name in the Java world. Now, combined with the PHPEclipse plugin, Eclipse offers a world-class development environment for PHP applications.

This article will help you get started with using Eclipse for PHP development. It provides an overview of the Eclipse Platform, information on the installation of Eclipse and PHPEclipse, the Eclipse interface, and some PHP-helpful features.

Eclipse is written in Java and its GUI is handled by the Eclipse Standard Widget Toolkit (SWT). This combination makes Eclipse a fast, cross-platform application. Pre-compiled binaries are available for all major operating systems including Mac OS X, Linux (GTK and Motif), Windows, and Solaris.

By itself, Eclipse does nothing. The core piece of Eclipse is just a small kernel. All functionality of the Eclipse platform is a result of interactions between plugins and the kernel. This includes the GUI and file system managers. Since Eclipse made its name as a Java development platform, a Java Development Toolkit (JDT) plugin is included with the standard Eclipse SDK for Java development.

The significance of this modular architecture cannot be overstated. It gives Eclipse a phenomenal amount of flexibility. Via plugins, not only is Eclipse a professional IDE for many languages, but it can also act as an interface for many other systems. With Eclipse, you can write Cobol code, and use it as a front end for an LDAP server. The number of plugins is so diverse and numerous that Eclipse Foundation maintains a separate site for the plugin community at http://www.eclipse-plugins.info/eclipse/index.jsp. A more compelling consequence of the architecture is its meaning for open source in general. No longer are developers tied to one proprietary tool, product, or closed license. With a C# plugin for Eclipse, you do not have to purchase Microsoft Visual Studio should you wish to develop in .NET. It is the open source method of embrace and extend.

For this article, I will focus on the PHPEclipse plugin for PHP development. A bit of warning - PHPEclipse, and this article, has a heavy Apache and MySQL bias. PHPEclipse can work with other web servers and databases with very little functionality sacrifice.

You should have Java, Apache running PHP, and MySQL installed locally. If you are running Windows and do not have these components installed, consider following the wampp-based instructions on the PHPEclipse site: http://phpeclipse.de. If you already have a development web server/database environment, follow these basic instructions.

Download mirrors for Eclipse are available at the Eclipse Foundation website: http://www.eclipse.org/downloads/index.php

Download the latest version of the "Eclipse SDK" package for your operating system. The Eclipse SDK package has the complete IDE and the Java JDT. Uncompressing the SDK creates a directory called \eclipse. Move it to your favorite applications directory.

Download the PHPEclipse plugin, available on Sourceforge at http://sourceforge.net/project/ showfiles.php?group_id=57621.

After unzipping the plugin, place all decompressed files in the plugins directory of the eclipse directory. At a minimum, you will need these two packages for PHP development. Additional features may require other software installations, as noted.

When Eclipse launches, it will ask you where you would like to place your Workspace. Your Workspace is where all the files in your application go. Traditionally, this is placed in your individual user directory or a separate workspace directory under the eclipse application directory. If you do primarily web development, you may consider placing this in the DocumentRoot directory of your web server.

After Eclipse finishes startup (yes, it may take a while), you'll be presented with the main Eclipse interface. The overall GUI is called the Workbench. In Eclipse, each tab is called a view. The arrangement of views is a perspective. Each perspective is geared towards a certain task. Debugging has a perspective. Java development, PHP development, and CVS integration are examples of other perspectives. By default, you should see the Resource Perspective, which is a general-purpose default perspective.

Across the top, there is the Navigator View, which shows file system resources and the file structure of each project. Next to that is the Editor. The Editor is used to edit code. In the far right is the Outline view. The Outline is used to display the hierarchy of something, depending on what perspective is using the Outline. In Java and PHPEclipse Perspectives, the Outline shows classes and their methods. The pane below is a miscellaneous pane that displays views dependent on the perspective. PHPEclipse Perspective puts web browser and system console panes here by default.

To change perspectives, go to the Window -> Open Perspective, or use the Shortcut Toolbar in the upper right corner. Several other options in the Window menu allow you to customize perspectives. To open views, go to Window -> Show View. For both these submenus, certain views and perspectives may be hidden. Select the "Other..." option to view everything available.

Eclipse manages applications and websites by projects. To create a new project go to File -> New -> Project... For PHP projects, select the PHP Project option. This will lead you through a wizard and the end project will appear in the Navigation view. To add pages or files, select File -> New -> PHP File. You can also add subdirectories and create your whole site hierarchy from here. Each item appears in the tree structure of the Navigation view. When you click on a PHP file, it will open in the Editor for editing.

The Editor alone is worth the price of admission. In addition to being well versed in syntax highlighting, The Editor also knows all the PHP functions and HTML tags. Within <?php and ?> tags, try typing "mysql" and then hit Control and Space. All functions beginning with "mysql" will appear. Select the one you want and hit Enter. You can see all HTML tags when you are outside of the php directive tags. Type "<" and hit Control and Space. This is the Eclipse template system at work. A template is also available in the Java Development Perspective for the standard Java Class Libraries.

As with any good IDE, PHPEclipse has a debugger to set breakpoints, step through code, and monitor variable values along the way. In the Editor, double click on the column just to the left of the line number to set a breakpoint. To debug, click on the file and select Run -> Debug As -> PHP Application. This will activate the Debug Perspective. From the Debug View, you can step through code. The Variables View shows all application and environment variables, and their values.

The installation of the debugger is not for those with weak stomachs. Moreover, as of this writing, there are a few reported bugs in the debugger of the latest version of PHPEclipse. For Windows users, if you follow PHPEclipse's wampp-based instructions, it should work. For other platforms, you should use the dbg section from those instructions as general guidelines. You will need to install and configure the dbg debugger PHP extension available at http://dd.cron.ru/dbg/downloads.php. PHPEclipse acts as a client to this extension.

The Standard Widget Toolkit includes a web browser, called the SWT Browser Widget. Eclipse uses the Widget to view HTML documents as if a web browser were requesting them. The Widget's rendering engine is dependent on your operating system - KHTML for Mac OS X, Gecko for Linux, and MSHTML for Windows. Every time you save a file in the Editor, the Browser widget will make a request for the edited page from the local web server.

To activate the Browser Widget preview, you'll need to specify your local web server's DocumentRoot and localhost address in the Eclipse Preferences. Go to Window -> Preferences -> PHPEclipse Web Developer -> Project Defaults. You'll also need to make sure the project is in the DocumentRoot directory. If you didn't specify the default workspace to the DocumentRoot, you can override project locations by right clicking on each project and selecting Properties.

With the Quantum DB Perspective, you can interface with a database directly from Eclipse. In the SQL Editor, you can write SQL statements against a database and have the result set appear in the Quantum Table View. You can also browse the schema of a database in the Database Bookmarks and Quantum Table Views.

The Quantum Perspective acts as a client to a database using a JDBC connection. Your database must have a JDBC driver installed. For MySQL, the official MySQL Connector/J driver is available at http://dev.mysql.com/downloads/connector/j/3.0.html. Once you have this installed, you need to create a bookmark for each database by right-clicking in the Database Bookmarks View. Eclipse will prompt you for the location of the driver and all the database settings.

Hopefully, this article will get you up and running with Eclipse and PHPEclipse, and convince you that this is the right PHP development platform for you. This is just a very brief introduction to Eclipse's functionality. There are many other features, settings, and plugins to explore. As you discover more functionality, odds are that you'll find Eclipse even more useful. With widespread industry support, an extensible architecture, and an open source license, Eclipse is an important player in freedom of software choice and makes your PHP development easier.