OGC Publish OGC Find

26 Copyright © 2015 Open Geospatial Consortium.

5.2 Publish-Find-Bind in the OGC World

When studying the concept of OGC Web Services and the approach to Publish-Find- Bind, one will find that the established procedure is different than UDDI. Because the goal of this ER is to find options to describe Common Security across all OGC Web Service standards and make recommendations on the best options isare, studying the OGC way of Publish-Find-Bind in more detail is essential.

5.2.1 OGC Publish

For OGC Web Service instances, typically two types of descriptions are uploaded to a registry: 1 An ISO-19115 compliant metadata document that focuses on describing the dataset 2 An ISO compliant metadata document that focuses on describing the actual service instance with a link to the ISO metadata for served the data set From the perspective of Common Security, the description of the data set is not of any concern, as it has no implications to the actual Bind process. However, license and use restrictions on the data set might be in place and must be honored when receiving the data via the providing service. The interesting bit from the perspective of Common Security is the ISO metadata description for the service instance. The options available to include or link to security constraint description of implemented frameworks are addressed in more detail in a later section of this ER.

5.2.2 OGC Find

The find process usually involves querying a CSW, which is able to search one or multiple registries of ISO-19115 compliant metadata records. The result of a find process is one or many ISO metadata files. Each file either describes characteristics of a data set or a service instance. Notice that the result of the OGC Find process is not a WSDL document that enables a developer to implement a client. Instead, the ISO metadata file contains the service base URL that enables the client to execute the GetCapabilities operation. The result of the GetCapabilities operation the Capabilities document enables the client to fully bind with the service. Copyright © 2015 Open Geospatial Consortium. 27 In case that Common Security is in place for the service, these constraints can be advertised in both documents: i the ISO metadata and ii the OGC Capabilities document. However, taking under consideration that the metadata file is used of human consumption, it is not necessary to encode the constraints introduced by the Common Security to be machine-readable. However, this can’t hurt as using machine-readable encoding enables to properly visualize the service characteristics to the user, in particular the existing security constraints. Because the client always uses the service base URL and the GetCapabilities operation to bind with the service instance, the ability to describe Common Security constraints inside the Capabilities document in a machine-readable fashion seems to be mandatory.

5.2.3 OGC Bind