The catalog service provides a list of all available services for your area. Exploration of OData services is crucial for several tools to identify a suitable service for the realization of a business use case. Therefore certain search capabilities are required.
Metadata exploration is available using standard OData mechanisms. It is built on top of OData Channel to have full OData feature support when accessing the local database. Exposure of metadata uses search capabilities (scanning the English version of a description of a service), for example, search for all service documents where SalesOrder is used in the description.
Exploration of the remote OData Channel's services and the registration of its services on SAP Gateway is also provided.
The catalog service retrieves a list of all available services on SAP Gateway. It is based on a catalog service pattern proposed by Microsoft™ and consists of an implementation approach of the catalog service pattern in the context of SAP Gateway.
There are two versions of the catalog service available in SAP Gateway, Version 1 and Version 2. Version 2 has EntitySet collection, Tag collection, Vocabulary collection and Annotations. The open search functionality is also enhanced in Version 2. You can choose the version based on your requirement.
External tools and developers can use this service to retrieve all available OData services, which are exposed on one dedicated SAP Gateway system. The catalog service thus acts as a central entry point to access a list of available services.
The following functionality is offered:
Free text search is now based on the service description, service ID, service name.
Filtering which means that all attributes can be set to filterable
Support of the delta token functionality
EntitySet Collection: The EntitySet collection lists all the entity sets that are available in different services. This cannot be created / deleted / updated from the client.
Tag Collection: The Tag collection lists all the backend tags that are associated with various services. These tags cannot be deleted via catalog service.
For example, http://<server>:<port>/sap/opu/odata/IWFND/CATALOGSERVICE;v=2/ServiceCollection('%2FIWFND%2FSG_MED_CATALOG_0002')/Tags. Here,%2FIWFND%2FSG_MED_CATALOG_0002 is the associated service.
Open search also covers EntitySet collection and Tag collection while searching. For example, if we do an open search with FlightCollection it is expected to search for RMTSAMPLEFLIGHT service.
The catalog service is available via the following URL:
The following pictures show an example catalog service, first the service document, then the service metadata document.
For some applications the service calls are made using the SID: this is the ABAP system ID. This does not correspond to the SAP Gateway system alias. To allow these applications to also use standard requests via the SAP Gateway system alias, you need a mapping from SID to system alias. The service catalog has been enhanced by a function import which retrieves a list of system aliases for both client and system name.
An error is thrown if the client is wrong. An empty response is displayed if both client and system are ok but there is no result as to the system alias.