Book Image

The PEAR Installer Manifesto

By : Gregory Beaver
Book Image

The PEAR Installer Manifesto

By: Gregory Beaver

Overview of this book

PEAR stands for PHP Extension and Application Repository, and its primary purpose is to support code re-use. PEAR provides both an advanced installer and a code repository at http://pear.php.net. PEAR code is organized into discrete re-usable components called packages. A package consists of a group of files and a descriptor file called package.xml that contains metadata about the package's contents, such as the package version, any special dependencies, and textual information such as the package description and authors. The software that transforms a package from an inert grouping of files into a dynamic software package is called the PEAR Installer and is itself a PEAR package. In other words, the PEAR Installer can be used to upgrade itself. It truly is a very powerful application. In short, the PEAR Installer is one of the most effective tools for managing a high-quality software library, high-quality applications, or high-quality websites. This book will show you a new way of organizing your PHP development, by leveraging the full power of the PEAR Installer. In a sense, the PEAR Installer is a step above a software design pattern, a meta-development pattern that can be used to systematically organize all of your PHP development. You will learn how to organize your code into packages using the package.xml format. You will learn about the revolutionary new PEAR Channel concept, and how to safely and reliably depend on external PHP libraries from sources such as pear.php.net and other PEAR channels. You will learn about the PEAR_PackageFileManager package, and how to customize individual installations of your PHP code through file roles, file tasks, and post-installation scripts. In addition, you will learn how to use the power of PEAR to manage your web projects with the PEAR installer to bring the power of versioning and rollbacks to your live website. The synergy of the PEAR Installer and a revision control system like CVS or Subversion is also explored in depth. Next, you will learn how to set up your own PEAR Channel for distributing PHP applications, both open-source and proprietary closed-source PHP applications that can be secured using technology already built into the PEAR Installer. Finally, you will learn how to embed the PEAR Installer inside your own web application in order to manage plug-ins from a remote server. The book covers in detail designing a custom plug-in system for a fictitious blog application. The plug-in system is used to manage templates, and the PEAR Installer is used to manage the details of querying the remote server for templates, handling dependencies between versioning, and doing the actual installation process as well.
Table of Contents (11 chapters)
The PEAR Installer Manifesto
Credits
About the Author
About the Reviewers
Preface

Chapter 4. Clever Website Coordination Using the PEAR Installer

In the last two chapters, we learned how to use the PEAR installer's features to manage libraries and applications for public distribution. In this chapter, we'll learn how the PEAR installer can be used to make managing the contents of a complex and rapidly evolving website easy. In fact, the PEAR installer can be used to provide an extra level of insurance that a website will function as expected, and even make diagnosing problems easier.

In this chapter, we'll begin by understanding the details of our problem at a high level, and seeing how PEAR installer can help us to solve it. Then we'll look at the first step of the solution, setting up the source control system, and we will finally finish off with managing the complexity of a multi-segment website using a live site as an example.

Overview of the Problem

One of the most important tasks is keeping the structure of a complex and dynamic website coherent and up to date as...