LDES Subject Page Bucketizer


The purpose of the subject page bucketizer is to fragment the LDES members based on their versionOfPath. This bucketizer assumes URIs comply with the following structure: http(s)://{domain}/{type}/{concept}(/{reference})*, e.g. https://data.vlaanderen.be/id/gemeente/44001. As the {reference} represents the identifier of the object, this part is used to indicate the bucket.

> An LDES bucketizer adds triples with the ldes bucket predicate (https://w3id.org/ldes#bucket) to the array of quads representating an LDES member, indicating the bucket in which the member belongs.

Example

Assume the following member:

``ttl
dct:created "2002-08-13T16:33:18+02:00"^^xsd:dateTime ;
dct:isVersionOf ;
prov:generatedAtTime "2021-09-07T15:44:05.975Z"^^xsd:dateTime .
`

After passing the subject page bucketizer, the member will have an extra triple:
`ttl
dct:created "2002-08-13T16:33:18+02:00"^^xsd:dateTime ;
dct:isVersionOf ;
prov:generatedAtTime "2021-09-07T15:44:05.975Z"^^xsd:dateTime ;
ldes:bucket "123"^^xsd:string .
`

Install

`bash
> npm i @treecg/ldes-subject-page-bucketizer
`

Usage

A bucketizer should always be used in combination with the LDES client. More information on how to setup an LDES client can be found here. It is important to set the option in the LDES client to receive the LDES member as an array of quads: representation: 'quads'.

The bucketizer expects a valid property path

`
import { SubjectPageBucketizer } from '@treecg/subject-page-bucketizer'

const run = async (): Promise => {
const options = {...};
const url = ...;

const bucketizer = await SubjectPageBucketizer.build({ propertyPath: ''});

const ldes = LDESClient.createReadStream(url, options);
ldes.on('data', (member) => {
bucketizer.bucketize(member.quads, member.id)

// Continue processing the member, but now the array of quads will have an extra triple, the bucket triple
});
}

run().catch(error => console.error(error.stack));
``