dcat:distribution in dcat:DataSets

[arnoweiss]

The catalog-requests return data in the structure of dcat:DataSets that look as follows. Please note the dcat:distribution section.

{
  "@id": "10b1b0f3-5a67-4eee-9404-5a300356a50d",
  "@type": "dcat:Catalog",
  "dcat:dataset": [
    {
      "@id": "<ASSET-ID>",
      "@type": "dcat:Dataset",
      "odrl:hasPolicy": {
        "@id": "Y29udHJhY3QtZ2V0LTE=:anNvbi1nZXQtMQ==:MDEwODg2ZTItZDhmNi00Y2NjLWFhMWYtY2U2Y2JmYjlmMWQz",
        "@type": "odrl:Set",
        "odrl:permission": {
          "odrl:target": "<ASSET-ID>",
          "odrl:action": {
            "odrl:type": "http://www.w3.org/ns/odrl/2/use"
          },
          "odrl:constraint": {
            "odrl:leftOperand": "https://w3id.org/tractusx/v0.0.1/ns/Membership",
            "odrl:operator": {
              "@id": "odrl:eq"
            },
            "odrl:rightOperand": "active"
          }
        },
        "odrl:prohibition": [],
        "odrl:obligation": [],
        "odrl:target": "<ASSET-ID>"
      },
      "dcat:distribution": [
        {
          "@type": "dcat:Distribution",
          "dct:format": {
            "@id": "HttpProxy"
          },
          "dcat:accessService": "b4f2c6b6-d3d1-46e2-a517-6912b7f8a509"
        },
        {
          "@type": "dcat:Distribution",
          "dct:format": {
            "@id": "AmazonS3"
          },
          "dcat:accessService": "b4f2c6b6-d3d1-46e2-a517-6912b7f8a509"
        }
      ],
      "edc:description": "Json Get Asset",
      "edc:id": "<ASSET-ID>",
      "dct:type": {
        "@id": "https://my-namespa.ce/my-asset-type"
      }
    }
  ],
  "dcat:service": {
    "@id": "b4f2c6b6-d3d1-46e2-a517-6912b7f8a509",
    "@type": "dcat:DataService",
    "dct:terms": "connector",
    "dct:endpointUrl": "https://provider-data.plane/api/v1/dsp"
  },
  "edc:participantId": "BPNL000SAP000003",
  "@context": {
    "dct": "https://purl.org/dc/terms/",
    "tx": "https://w3id.org/tractusx/v0.0.1/ns/",
    "edc": "https://w3id.org/edc/v0.0.1/ns/",
    "dcat": "https://www.w3.org/ns/dcat/",
    "odrl": "http://www.w3.org/ns/odrl/2/",
    "dspace": "https://w3id.org/dspace/v0.8/"
  }
}

dcat:distribution currently always returns the two entries - one with the format "AmazonS3" and one with "HttpProxy" as dcat:format. As I understand the definition of this section in the context of an EDC, this should signify the means a consumer can use to access the data - in this case either the Http- or S3-Data-Planes. In its current behavior, the two distribution methods are returned independent of the èdc:type that was set by the Data Provider in the POST /v3/assets's DataAddress object. So here's a couple of hypotheses to discuss:

• The catalog should return only those dcat:distributions that the backend's data is actually available via.
• dcat:accessService should contain a resource, not a literal.
• The range of edc:type (currently AmazonS3, HttpData) and dct:format (AmazonS3 , HttpProxy) should be the same.