Overview of Edge components customization

This book discusses the application programming interfaces (APIs) provided for the Edge components of WebSphere® Application Server. (The Edge components of WebSphere Application Server include Caching Proxy and Load Balancer.) Several interfaces are provided that enable administrators to customize their installations, to alter how the Edge components interact with each other, or to enable interaction with other software systems.

IMPORTANT: Caching Proxy is available on all Edge component installations, with the following exceptions:

The APIs in this document address several categories.

Caching Proxy customization

The Caching Proxy has several interfaces written into its processing sequence where custom processing can be added or substituted for standard processing. Customizations that can be executed include altering or augmenting tasks like the following:

Custom application programs, which are also known as Caching Proxy plug-ins, are called at predetermined points in the proxy server's processing sequence.

The Caching Proxy API has been used to implement certain system features. For example, the proxy server's LDAP support is implemented as a plug-in.

The Caching Proxy API describes the interface in detail and includes steps for configuring the proxy server to use plug-in programs.

Load Balancer customization

The Load Balancer can be customized by writing your own advisors. Advisors perform the actual load measurement on the servers. With a custom advisor, you can use a method that you provide and that is relevant to your system to measure the load. This is especially important if you have customized or proprietary Web server systems.

Custom advisors provides detailed information about writing and using custom advisors. It includes sample advisor code.

Locating sample code

Sample code for these APIs is included on the Edge Components CD-ROM, in the samples directory. Additional code samples are available from the WebSphere Application Server Web site, www.ibm.com/software/webservers/appserv/