Response Exceptions GetMessage operation optional

Copyright © 2006 Open Geospatial Consortium, Inc. All Rights Reserved. 29 If the service knows the given ID he will return the message in the response: ?xml version=1.0 encoding=UTF-8? GetMessageResponse xmlns = http:www.opengis.netwns xmlns:xsi = http:www.w3.org2001XMLSchema- instance xsi:schemaLocation = http:www.opengis.netwns ..wns.xsd Message NotificationMessage ServiceDescription ServiceType SPS ServiceType ServiceTypeVersion 0.0.30 ServiceTypeVersion ServiceURL ServiceURL ServiceDescription Payload sps:SPSMessage SPSCorrID = 1161690976970_684004688690043 xmlns:sps = http:www.opengis.netsps sps:StatusInformation sps:status New data available sps:status sps:StatusInformation sps:SPSMessage Payload NotificationMessage Message GetMessageResponse Otherwise, he will issue an exception with code UnkownUserID . 8 Common notification mechanism

8.1 Introduction

OGC provides many specifications for Web services that either provide data, the ability to gather data or to process data. With algorithms getting more complex and the amount of data getting bigger we are faced with the problem that communication via HTTP i.e., sending a request and receiving the response can no longer be said to happen in a synchronous way. We rather have reached the point where we need mechanisms for asynchronous communication between clients and Web services. Given that we are using SOAP over HTTP we can use WS-Addressing GUDGIN et al. 2006, which provides a mechanism for asynchronous communication between Web services. The default transport protocol is HTTP, but a client can also provide destinations that require other protocols. Here we want to provide a mechanism that supports asynchronous communication between OGC Web services even if SOAP is not used. The schema elements provided in this chapter can be taken as building blocks that can be used: • to indicate which communication protocols a service supports, • to indicate which message formats a service supports, • to provide a common way for services to request communication endpoint information from the client and