Web services

Web services are a technology that invokes services or applications using Internet standards and protocols. You can read this topic to learn about the core technologies on which Web services are developed and implemented.

If you have an existing application, and you want to make the service that your application provides available to others - either within your own organization or beyond it - you can use Web services technologies to provide a standard Web interface for your service. Web services can be defined as middleware that connects applications together no matter how each application is implemented or where it is located.

Web services operate at a level of abstraction that is similar to the Internet; they can work with any operating system, hardware platform or programming language that can be Web-enabled and are one of the technologies that you can use to implement a service-oriented architecture (SOA).

New or updated for this feature pack The WebSphere Application Server Version 6.1 Feature Pack for Web Services introduces additional Web services standards that support interoperable and reliable Web services applications. These additional standards support asynchronous messaging, which means that your applications can exchange messages reliably even if one of the parties is temporarily offline, busy, or not available. You can be confident that your communication is reliable and reaches its destination while interoperating with other vendors.

The core technologies on which Web services are developed and implemented include:

WebSphere Application Server also provides other mechanisms that can help you get the most out of your Web services:

A private Universal Description, Discovery and Integration (UDDI) registry
A private UDDI registry provides a way to publish and discover information about Web services that are available within and through your organization. You can use it to make your Web services available to people within your organization, or beyond your organization. A group of companies can use it to share their Web services, or to make them available to others outside the group. At its simplest, a private UDDI registry does for Web services what a business telephone directory does for business addresses and telephone numbers. However, a private UDDI registry is much more than just a directory. It needs to be in order to harness the considerable power and flexibility of Web services. If you publish your Web service to UDDI, you make it available for other people or applications to discover and reuse. This saves development time, effort and cost, and helps minimize the need to maintain several different implementations of the same application.
A Web Services Invocation Framework (WSIF)
SOAP bindings for Web services are part of the WSDL specification. So when you think of using a Web service, you probably think of assembling a SOAP message and sending it across the network to the service endpoint, using some SOAP client API. The WSDL specification allows for extensibility points which can describe alternate ways of invoking a Web service. A WSIF client can make use of these non-SOAP descriptions to invoke a service in a more efficient way. For example, a Web service provider might offer a SOAP binding for the service and a local Java binding that allows you to treat the local service implementation (a Java class) as a Web service. If the client is deployed in the same environment as the service, then the local Java binding for the service can be used. This provides more efficient communication with the service by making direct Java calls rather than sending and receiving SOAP messages.
To deploy a Web service as a WSIF-enabled service, you first develop and deploy the Web service, then you develop the WSIF client based on the WSDL document for that Web service.
Web services and service integration technologies

Web services can use the service integration bus and the Web services gateway to provide a single point of control, access, and validation of Web service requests and to allow control of Web services that are available to different groups of Web service users.

With service integration bus-enabled Web services, you can achieve the following goals:
  • Take an internally-hosted service that is available at a bus destination, and make it available as a Web service.
  • Take an externally-hosted Web service, and make it available internally at a bus destination.
  • Use the Web services gateway to map an existing service - either an internal service, or an external Web service - to a new Web service that appears to be provided by the gateway.

For more information, see Enabling Web services through service integration technologies.

WS-Notification

WS-Notification enables Web services to use the "publish and subscribe" messaging pattern. In this pattern a producing application inserts (publishes) a message (event notification) into the messaging system, having marked it with a topic that indicates the subject area of the message. Consuming applications that have subscribed to the topic and have the appropriate authority, receive an independent copy of the message that was published by the producing application.

WS-Notification also allows interchange of event notification between WS-Notification applications and other clients of the service integration bus. By exploiting other service integration bus functionality, you can also use this function to interchange messages with other IBM publish and subscribe brokers such as Event Broker or Message Broker.

Learn more about WS-Notification.

WS-Reliable Messaging New or updated for this feature pack
With WS-Reliable Messaging, you can make your SOAP over HTTP-based Web services interoperable and reliable without having to write custom code. For more information, see Adding assured delivery to Web services through WS-Reliable Messaging.
WS-Security 1.1 enhancements New or updated for this feature pack
The WS-Security 1.1 standard brings several new enhancements to the security component, including Web Services Secure Conversation (WS-SecureConversation) and Web services policy sets.
Web Services SecureConversation (WS-SecureConversation) New or updated for this feature pack
WS-SecureConversation provides a secured session for long running message exchanges and leveraging of the symmetric cryptographic algorithm. The symmetric cryptographic algorithm provides better performance and throughput when compared to the asymmetric cryptographic algorithm.
Web Services Addressing (WS-Addressing) enhancements New or updated for this feature pack

Web Services Addressing (WS-Addressing) is a Worldwide Web Consortium (W3C) specification that aids interoperability between Web services by defining a standard way to address Web services and provide addressing information in messages. The WS-Addressing specification introduces two primary concepts: endpoint references and message addressing properties.

Web Services Distributed Management (WSDM) New or updated for this feature pack
Web Services Distributed Management (WSDM) is an OASIS approved standard that supports managing resources through a standardized Web service interface. Your environment, such as WebSphere Application Server host or an operating system host that has an exposed resource as a Web service within a single interface is used to manage and control resources. WSDM provides a new way to expose the internal product administration functions for a Web service interface.



Related concepts
New or updated for this feature pack What is new in the Version 6.1 Feature Pack for Web Services
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