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8.2.5 Web Notification Service
Name Web Notification Service
Standard Specifications
OGC 06-095r1, OpenGIS® Web Notification Service Discussion Paper Description
The Web Notification Service WNS is a service by which a client may conduct asynchronous dialogues message interchanges with one or more
other services using a range of communication protocols. This service is useful when many collaborating services are required to satisfy a client
request, andor when significant delays are involved in satisfying the request and data have to be pushed to receivers using various protocols.
The “way-of-notification” palette may include e-mail, http-call as HTTP
POST: in case of sophisticated clients that act as web services themselves, SMS, Instant Message, phone call, letter or fax. A WNS has to provide at
least one of the described notification mechanisms. The Web Notification Service provides its functionality through the following
interfaces:
ServiceCapabilities : Provides information about both common and
specific capabilities. WebNotification
: Performs functions to send notifications to registered users and deal with responses.
Interface ServiceCapabilities getCapabilities
Requests the description about the capabilities of a service. In the particular case of a Web Notification Service, the response of a getCapabilities request
is general information about the service itself, specific information about the available notification protocols, and mandatory operational parameters. The
following questions have to be answered in the capabilities:
• What notification protocols are supported? • Which parameters are mandatory for registering?
• What kinds of response protocols are supported? Interface WebNotification
getWSDL This operation allows a client to request and receive the WSDL definition of
the server interface. register
Registers users to receive further notification. The user address and the communicationProtocol have to be provided. The WNS must provide a
UserID.
unregister Allows a user to unregister from that service instance
updateSingle User
Registration This operation allows a client to update a previous registration by providing a
new communication endpoint e.g. an email address or a telephone number.
opdateMulti User
Registration This operation allows a client to update a previous MultiUserRegistration by
adding or deleting individual group members.
doNotification Initiates the notification of a user.
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getMessage This operation allows a client to retrieve a message which has not been
delivered by the WNS because of restrictions set by the chosen transport protocol. If notification via SMS or phone call is desired then the WNS will
forward the contents of the ShortMessage element of the DoNotification request together with a unique ID assigned to that message for later retrieval
of the complete message via the GetMessage operation.
Example usage Observations that require preceding collection feasibility studies, complex control and management activities, or intermediate andor subsequent user
notifications are not conducive to synchronous operations, but instead favour asynchronous operations. For these cases, especially when a Sensor Planning
Service comes into play, asynchronous communications need to be supported. For example, in a request for a satellite image, the user submits a collection
feasibility request through a Sensor Planning Service and then subsequently requests collection of the desired observations. For this case, if any
procedures are finished, interrupted, delayed, timed out, or cancelled, the user must be notified.
If the feasibility request returns a positive response, the user would then request the observations. The requested data will probably not be ready for
immediate retrieval; there will likely be a delay. It is also possible that the service would not be able to provide an exact retrieval date-time. Thus, a
notification mechanism becomes necessary. The communication is never initiated by the Web Notification Service. This service acts as a message
transducer exclusively.
Comments This service description is abstracted from the OpenGIS® Web Notification
Service Discussion Paper.
Table 8-5: Description of the Web Notification Service
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Copyright © 2007-2009 SANY Consortium Page 144 of 233
8.3. Access Control Services
