Book Image

Enterprise Integration with WSO2 ESB

By : Prabath Siriwardena
Book Image

Enterprise Integration with WSO2 ESB

By: Prabath Siriwardena

Overview of this book

<p>The Enterprise Service Bus (ESB) serves as a key component in most of the enterprise grade deployments. In most cases, the ESB removes point-to-point dependencies in your system to build a highly-scalable, loosely-coupled solution. ESB is a key ingredient to build an SOA infrastructure, but it's not a must. Even with an ESB, if industry best practices and patterns are not followed, users will end up in a mess. This book will teach you the essentials to get started with WSO2 ESB and solve the most commonly-faced integration problems.</p> <p>The book starts by explaining the need for an ESB and the problems it solves. It will cover the most widely-used enterprise integration patterns, including Content Based Router, Dynamic Router, Splitter, Aggregator, Scatter &amp; Gather, Publish &amp; Subscribe, Detour, Service Chaining, Content Enricher and Message Broker. Learn how WSO2 ESB can bring third-party business messaging systems such as SAP, FIX, and HL7 into the SOA world, as well as how to integrate the Twitter connector into your business messaging flow.</p>
Table of Contents (14 chapters)
Enterprise Integration with WSO2 ESB
Credits
About the Author
Acknowledgement
About the Reviewers
www.PacktPub.com
Preface
Index

Proxy Service


A proxy service provides a well-defined SOAP endpoint to the outside. In most of the cases, a proxy service, as its name implies, proxies a real, concrete business service. A proxy service may or may not have a one to one mapping to a business service. It can simply provide a level abstraction over one concrete service or many other business services. In WSO2 ESB, a proxy service is built with an In-Sequence, an Out-Sequence, and a fault sequence.

In-sequence

A request message coming in to a given proxy service will hit the In-Sequence defined for that proxy service.

Out-sequence

A response message coming from a concrete or a business service will go through the Out-Sequence defined for the corresponding proxy service.

Fault-sequence

You can also associate a Fault-Sequence with a proxy service and it will get executed when an exception happens in a proxy operation. This sequence won't get executed for the exceptions thrown from the backend business services. Those will still go through the Out-Sequence.