Configuring a new View for an Event Stream

After having created an Event Stream, a view needs to be defined to be able to retrieve the data.

This can be done through the Admin API at the /admin/api/v1/eventstreams/{event stream}/views endpoint.

A view config needs to have the following structure:

  • A tree:viewDescription object with its subject referring to the event stream object
    • a tree:FragmentationStrategy object that contains an ordered rdf list of fragmentations.
    • a ldes:retentionPolicy object that contains a set of retention policies. When no retention policies are required, this is omitted.
    • a tree:pageSize object that marks how many members should be partitioned per fragment.

For more info, visit the Swagger API documentation.

Fragmentations

To provide a more structured overview of the data, a fragmentation list can be defined.

For a more detailed explanation on fragmentation, together with all the available options, visit the Fragmentations Subsection.

Retention Policies

To reduce the amount of historical data kept in the LDES Server, one can configure a set of retention policies.

For a more detailed explanation on retention policies, together with all the available options, visit the Retention Policies Subsection.

Example 

@prefix ldes: <https://w3id.org/ldes#> .
@prefix tree: <https://w3id.org/tree#> .
@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@prefix server: <http://localhost:8080/generic-eventstream/> .

server:view-name tree:viewDescription [
    a tree:fragmentationStrategy;
    tree:fragmentationStrategy  () ;
    tree:pageSize "10"^^<http://www.w3.org/2001/XMLSchema#int> ;
] .