Support in defining filterExpression as part of requesting a catalogue by user or federated catalogue

[marcofranke]

Situation:
I created a asset and uploaded it using /management/v3/assets. with this HTTP Body:

  "@context": {
    "@vocab": "https://w3id.org/edc/v0.0.1/ns/"
  },
  "@id": "GeneratorBearing",
  "properties": {
    "name": "GeneratorBearing PCF",
    "contenttype": "application/json"
  },
  "dataAddress": {
    "type": "HttpData",
    "name": "Test asset",
    "baseUrl": "http://basyx-python-sdk-http-server:80/api/v3.0/submodels/aHR0cHM6Ly9hZG1pbi1zaGVsbC5pby9pZHRhL1N1Ym1vZGVsVGVtcGxhdGUvQ2FyYm9uRm9vdHByaW50LzAvOS9kY2EwYmE2NC0wYTRmLTQ4YmEtYTc1MS1iYzZhYTUyNTAzMjg=",
    "proxyPath": "true"
  }```
  
  If I request the catalogue from a data consumer, I see it in the list of assets: 
URL: /management/v3/catalog/request
HTTP Body:

{
"@context": { "@vocab": "https://w3id.org/edc/v0.0.1/ns/" },
"counterPartyAddress": "http://providerschaffler:15182/protocol",
"protocol": "dataspace-protocol-http"
}

The response is:

{
"@id": "GeneratorBearing",
"@type": "dcat:Dataset",
"odrl:hasPolicy":{"@id": "Mg==:R2VuZXJhdG9yQmVhcmluZw==:N2MyNzUyYWYtY2RiYy00MGI0LWI3MGEtYjdmMGVkZjJiOTAw", "@type": "odrl:Offer", "odrl:permission":[],…},
"dcat:distribution":[{"@type": "dcat:Distribution", "dct:format":{"@id": "Med-PULL" },…],
"name": "GeneratorBearing PCF",
"id": "GeneratorBearing",
"contenttype": "application/json"
}

Then, I try to filter exactly for this item and the properties:
"properties": {
"name": "GeneratorBearing PCF"}, from the asset:

URL: /management/v3/catalog/request
HTTP Body:

{
  "@context": { "@vocab": "https://w3id.org/edc/v0.0.1/ns/", "edc": "https://w3id.org/edc/v0.0.1/ns/" },
  "counterPartyAddress": "http://providerschaffler:15182/protocol",
  "protocol": "dataspace-protocol-http",
  "querySpec": {
    "@type": "edc:QuerySpec",
    "edc:offset": 0,
    "edc:limit": 50,
  "filterExpression": [
    {
      "@type": "edc:Criterion",
      "operandLeft": "edc:properties.edc:name",
      "operator": "=",
      "operandRight": "GeneratorBearing PCF"
    }
  ]
  }
}

Response:

{
    "@id": "5153ed95-2a8d-4aa0-aba2-e859cf2cc0ea",
    "@type": "dcat:Catalog",
    "dcat:dataset": [
    ],
    "dcat:catalog": [
    ],
    "dcat:distribution": [
    ],
    "dcat:service": {
        "@id": "e4a23ae8-5445-41e7-b63d-d155fd8d4232",
        "@type": "dcat:DataService",
        "dcat:endpointDescription": "dspace:connector",
        "dcat:endpointURL": "http://providerschaffler:15182/protocol"
    },
    "dspace:participantId": "schaeffler",
    "@context": {
        "dcat": "http://www.w3.org/ns/dcat#",
        "dct": "http://purl.org/dc/terms/",
        "odrl": "http://www.w3.org/ns/odrl/2/",
        "dspace": "https://w3id.org/dspace/v0.8/",
        "@vocab": "https://w3id.org/edc/v0.0.1/ns/",
        "edc": "https://w3id.org/edc/v0.0.1/ns/"
    }
}

That means, he hasn't found it. The question is what is wrong? I tried to find a tutorial with the latest syntax, but I failed. It would be great if you could explain it to me.

Thanks in Advance,
Kind regards,
Marco

[ndr-brt]

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