WS-Addressing
Encyclopedia
WS-Addressing or Web Services Addressing is a specification of transport-neutral mechanisms that allow web service
s to communicate addressing information. It essentially consists of two parts: a structure for communicating a reference to a Web service endpoint, and a set of Message Addressing Properties which associate addressing information with a particular message.
headers. Instead of relying on network-level transport to convey routing information, a message utilizing WS-Addressing may contain its own dispatch metadata in a standardized SOAP header. The network-level transport is only responsible for delivering that message to a dispatcher capable of reading the WS-Addressing metadata. Once that message arrives at the dispatcher specified in the URI, the job of the network-level transport is done.
WS-Addressing supports the use of asynchronous interactions by specifying a common SOAP header (wsa:ReplyTo) that contains the endpoint reference (EPR) to which the response is to be sent. The service provider transmits the response message over a separate connection to the wsa:ReplyTo endpoint. This decouples the lifetime of the SOAP request/response interaction from the lifetime of the HTTP request/response protocol, thus enabling long-running interactions that can span arbitrary periods of time.
structure encapsulating information useful for addressing a message to a Web service. This includes the destination address of the message, any additional parameters (called reference parameters) necessary to route the message to the destination, and optional metadata (such as WSDL
or WS-Policy
) about the service.
, IBM
, BEA
, Sun
, and SAP
and submitted to W3C for standardization. The W3C WS-Addressing Working Group has refined and augmented the specification in the process of standardization.
WS-Addressing is currently specified in three parts:
Web Services Policy Attachment for Endpoint Reference (WS-PAEPR) specifies the mechanism and meaning of including WS-Policy
expressions in Endpoint References. WS-PAEPR is a W3C Member Submission.
Web service
A Web service is a method of communication between two electronic devices over the web.The W3C defines a "Web service" as "a software system designed to support interoperable machine-to-machine interaction over a network". It has an interface described in a machine-processable format...
s to communicate addressing information. It essentially consists of two parts: a structure for communicating a reference to a Web service endpoint, and a set of Message Addressing Properties which associate addressing information with a particular message.
Description
WS-Addressing is a standardized way of including message routing data within SOAPSOAP
SOAP, originally defined as Simple Object Access Protocol, is a protocol specification for exchanging structured information in the implementation of Web Services in computer networks...
headers. Instead of relying on network-level transport to convey routing information, a message utilizing WS-Addressing may contain its own dispatch metadata in a standardized SOAP header. The network-level transport is only responsible for delivering that message to a dispatcher capable of reading the WS-Addressing metadata. Once that message arrives at the dispatcher specified in the URI, the job of the network-level transport is done.
WS-Addressing supports the use of asynchronous interactions by specifying a common SOAP header (wsa:ReplyTo) that contains the endpoint reference (EPR) to which the response is to be sent. The service provider transmits the response message over a separate connection to the wsa:ReplyTo endpoint. This decouples the lifetime of the SOAP request/response interaction from the lifetime of the HTTP request/response protocol, thus enabling long-running interactions that can span arbitrary periods of time.
Endpoint References
An Endpoint Reference (EPR) is an XMLXML
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
structure encapsulating information useful for addressing a message to a Web service. This includes the destination address of the message, any additional parameters (called reference parameters) necessary to route the message to the destination, and optional metadata (such as WSDL
Web Services Description Language
The Web Services Description Language is an XML-based language that is used for describing the functionality offered by a Web service. A WSDL description of a web service provides a machine-readable description of how the service can be called, what parameters it expects and what data structures...
or WS-Policy
WS-Policy
WS-Policy is a specification that allows web services to use XML to advertise their policies and for web service consumers to specify their policy requirements.WS-Policy is a W3C recommendation as of September 2007....
) about the service.
Message Addressing Properties
Message Addressing Properties communicate addressing information relating to the delivery of a message to a Web service:- Message destination URIUniform Resource IdentifierIn computing, a uniform resource identifier is a string of characters used to identify a name or a resource on the Internet. Such identification enables interaction with representations of the resource over a network using specific protocols...
- Source endpoint -- the endpoint of the service that dispatched this message (EPR)
- Reply endpoint -- the endpoint to which reply messages should be dispatched (EPR)
- Fault endpoint -- the endpoint to which fault messages should be dispatched (EPR)
- Action -- an action value indicating the semantics of the message (may assist with routing the message) URIUniform Resource IdentifierIn computing, a uniform resource identifier is a string of characters used to identify a name or a resource on the Internet. Such identification enables interaction with representations of the resource over a network using specific protocols...
- Unique message ID URIUniform Resource IdentifierIn computing, a uniform resource identifier is a string of characters used to identify a name or a resource on the Internet. Such identification enables interaction with representations of the resource over a network using specific protocols...
- Relationship to previous messages (A pair of URIUniform Resource IdentifierIn computing, a uniform resource identifier is a string of characters used to identify a name or a resource on the Internet. Such identification enables interaction with representations of the resource over a network using specific protocols...
s)
History
WS-Addressing was originally authored by MicrosoftMicrosoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
, IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
, BEA
BEA Systems
BEA Systems, Inc. specialized in enterprise infrastructure software products known as "middleware", which connect software applications to databases and was acquired by Oracle Corporation on April 29, 2008.- History :...
, Sun
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
, and SAP
SAP AG
SAP AG is a German software corporation that makes enterprise software to manage business operations and customer relations. Headquartered in Walldorf, Baden-Württemberg, with regional offices around the world, SAP is the market leader in enterprise application software...
and submitted to W3C for standardization. The W3C WS-Addressing Working Group has refined and augmented the specification in the process of standardization.
WS-Addressing is currently specified in three parts:
- The Core specification of Endpoint References and Message Addressing Properties.
- A binding of these properties to SOAPSOAPSOAP, originally defined as Simple Object Access Protocol, is a protocol specification for exchanging structured information in the implementation of Web Services in computer networks...
. - The Metadata specification defines how the abstract properties defined in Core are described using WSDLWeb Services Description LanguageThe Web Services Description Language is an XML-based language that is used for describing the functionality offered by a Web service. A WSDL description of a web service provides a machine-readable description of how the service can be called, what parameters it expects and what data structures...
, how to include WSDL metadata in endpoint references, and how WS-PolicyWS-PolicyWS-Policy is a specification that allows web services to use XML to advertise their policies and for web service consumers to specify their policy requirements.WS-Policy is a W3C recommendation as of September 2007....
can be used to indicate the support of WS-Addressing by a Web service.
Web Services Policy Attachment for Endpoint Reference (WS-PAEPR) specifies the mechanism and meaning of including WS-Policy
WS-Policy
WS-Policy is a specification that allows web services to use XML to advertise their policies and for web service consumers to specify their policy requirements.WS-Policy is a W3C recommendation as of September 2007....
expressions in Endpoint References. WS-PAEPR is a W3C Member Submission.