/derive Endpoint

Warning As of ESS 2.3, this endpoint has been deprecated. Please use the /query endpoint instead.

ESS supports an authorization mechanism based on Access Requests and Grants.

ESS serializes the access requests and grants as Verifiable Credentials (VCs) and provides an endpoint that queries Access Requests/Grants VCs and returns the matching VCs in a Verifiable Presentation (VP).

`/derive` Endpoint

The ESS Access Grant Service provides an endpoint with the following URL:

https://vc.<ESS DOMAIN>/derive

Note Access to the /derive endpoint requires users to be authenticated. The endpoint supports the use of either Solid-OpenID Connect (OIDC) access token or UMA token.

To query for /derive Access Requests/Grants, clients can send a derivation request to the endpoint:

Method

POST

Content-Type

application/json

Endpoint

https://vc.<ESS DOMAIN>/derive

Payload

Derivation request object.

Behavior

The ESS’ /derive endpoint implements the derive credential portion of the VC API specification with the following exceptions:

ESS’ /derive endpoint returns a VP instead of a VC.
ESS’ /derive endpoint, by default, excludes both expired VCs (i.e., VCs with expirationDate in the past) and future VCs (i.e., VCs with issuanceDate in the future). To override, see options.

The endpoint queries the user-associated Access Requests/Grants (regardless of revocation status) to return a VP that contains the matching Access Requests/Grants VCs.

User-associated Access Requests are requests that have either:
- The credentialSubject.id set to the user’s WebID (i.e., the request is created by the user); or
- The credentialSubject.hasConsent.isConsentForDataSubject set to the user’s WebID (i.e., the request is made to the user).
User-associated Access Grants are grants that have either:
- The credentialSubject.id set to the user’s WebID (i.e., the grant is created by the user); or
- The credentialSubject.providedConsent.isProvidedTo set to the user’s WebID (i.e., the grant is given to the user).

Input: Verifiable Credential

The endpoint accepts a JSON document of the form:

{
  "verifiableCredential": <VC to filter/query by>,
  "options": {
    "include": "ExpiredVerifiableCredential"
  }
}

Field

Description

verifiableCredential

Specify a filter Access Requests/Grants VC. The filter VC acts similarly to a “search-by-example” model and can be minimal (i.e., can be missing fields or have empty values such as an empty array, an empty document) or comprehensive. However, if any of the following field paths appear in the filter VC and are non-empty, ESS Access Grant Services uses these non-empty field paths to filter Access Requests/Grants VCs:

options

Optional. Specify the "include": "ExpiredVerifiableCredential" option to include expired VCs and future VCs in the returned VP.

"options": {
  "include": "ExpiredVerifiableCredential"
}

Omit to exclude the expired and future VCs. If you specify a different option or value (such as "include": "ExpiredVerifiableCredentials" with an s), the endpoint ignores the option and excludes the expired and future VCs.

Filter Paths

`id`

If the id field is present in the filter Access Requests/Grants VC, the ESS Access Grant Service considers the field for filtering user-associated Access Requests/Grants.

"id": <value>

If the id (i.e., the URL) of an access request/grant is known, you can use the id filter field to return a specific Access Requests/Grants in the output.

A user can also directly fetch an Access Requests/Grants (if associated with the user) by its id (i.e., URL). If fetching directly, the returned object is the VC instead of a VP.

`type`

If the type field is present in the filter Access Requests/Grants VC, the ESS Access Grant Service considers the field for filtering user-associated Access Requests/Grants VCs.

"type": <value(s)>

Note If the type value is a non-empty array, matching VCs must include all elements in that array. The matching VCs can have additional elements in the array; that is, the matching VCs are not restricted to just the elements specified in the filter array.

You can use the type field to query specifically for access requests or specifically for access grants.

For Access Requests

To query for Access Requests, you can specify filter "type": [ "SolidAccessRequest" ] :

"type": [ "SolidAccessRequest" ]

For Access Grants

To query for Access Grants, you can specify "type": [ "SolidAccessGrant" ] :

"type": [ "SolidAccessGrant" ]

`credentialSubject`

If the credentialSubject field is present in the filter Access Requests/Grants VC, and is not empty (i.e., it is not an empty document and contains at least one non-empty field path) , the ESS Access Grant Service considers the non-empty credentialSubject field paths to filter user-associated VCs.

"credentialSubject": {
  "id": <value>,
  <"hasConsent"|"providedConsent">:  {
     //...
  }
}

For Access Request VCs

In Access Requests, the credentialSubject field contains an id field and a credentialSubject.hasConsent field. When querying for Access Requests, you can query by any non-empty combination of the fields.

"credentialSubject": {
  "id": <value>,                            // The requestor's WebID
  "hasConsent": {
    "mode": <value or array of values>
    "hasStatus": <value>,
    "isConsentForDataSubject": <value>,     // The resource owner's WebID
    "forPersonalData": <value or array of values>,
    "forPurpose": <value or array of values>
  }
}

Note For fields that can be a single value or an array of values,

A single value is equivalent to an array with a single element.
To filter by an array, matching VCs must include all elements in the provided array. However, the matching VCs can have additional elements in the array; that is, the matching VCs are not restricted to just the elements specified in the filter array.

That is:

<field>: "foo" condition would match:
- <field>: "foo"
- <field>: [ "foo" ]
- <field>: [ "foo", "other string" ]
<field>: [ "foo" ] condition would match:
- <field>: "foo"
- <field>: [ "foo" ]
- <field>: [ "foo", "other string" ]

For Access Grant VCs

In Access Grants, the credentialSubject field contains an id field and a credentialSubject.providedConsent field. When querying for Access Grants, you can query by any non-empty combination of the fields.

"credentialSubject": {
  "id": <value>,                   // The resource owner(grantor)'s WebID
  "providedConsent": {
    "mode":  <value or array of values>,
    "hasStatus": <value>,
    "isProvidedTo": <value>,       // The grant recipient's WebID
    "forPersonalData": <value or array of values>,
    "forPurpose": <value or array of values>
  }
}

Note For fields that can be a single value or an array of values,

To filter by an array, matching VCs must include all elements in their array. However, the matching VCs can have additional elements in the array; that is, the matching VCs are not restricted to just the elements specified in the filter array.

That is:

<field>: "foo" (or <field>: ["foo"] ) condition would match:
- <field>: "foo"
- <field>: [ "foo" ]
- <field>: [ "foo", "other string" ]
<field>: [ "foo", "bar" ] condition would match:
- <field>: [ "foo", "bar" ]
- <field>: [ "foo", "bar", "something else" ]

Empty credentialSubject

ESS Access Grant Service only considers non-empty credentialSubject field paths to filter user-associated Access Requests/Grants. Empty credentialSubject field paths are not considered as part of the filter. Examples of empty credentialSubject field paths are:

"credentialSubject": {
}

"credentialSubject": {
   "hasConsent": {}
}

"credentialSubject": {
   "hasConsent": {
      "mode": [],
      "forPersonalData": []
   }
}

"credentialSubject": {
   "providedConsent": { }
}

"credentialSubject": {
   "providedConsent": {
       "mode": []
   }
}

`issuer`

If the issuer field is present in the filter Access Requests/Grants VC, the ESS Access Grant Service considers the field for filtering user-associated Access Requests/Grants VCs.

"issuer": <value>

Output: Verifiable Presentation

The /derive endpoint returns a Verifiable Presentation containing the matching Access Requests/Grants VCs:


{
  "@context": [
    "https://www.w3.org/2018/credentials/v1",
    "https://w3id.org/security/data-integrity/v1",
    "https://w3id.org/security/suites/ed25519-2020/v1"
  ],
  "holder": "https://vc.<ESS Domain>",
  "type": "VerifiablePresentation",
  "verifiableCredential": [
    { // Matching access request/grant VC },
    { // Matching access request/grant VC },
    ...
  ]
}

Examples

ESS Access Grant Service performs a match on non-empty id, credentialSubject , issuer , and type field paths present in the filter VCs.

Note In the following examples, the filters return user-associated Access Requests/Grants (both active and revoked) that match the filter field paths. Because the payload does not specify the options: {“include”: “ExpiredVerifiableCredential” } , expired and future access requests/grants are excluded from the results.

Example 1

The following filter queries for user-associated Access Grants where owliverowner grants Read access to requestingrabbit .

{
   "verifiableCredential": {
      "@context": [
        "https://www.w3.org/2018/credentials/v1",
        "https://schema.inrupt.com/credentials/v2.jsonld"
      ],
      "type": [
         "VerifiableCredential",
         "SolidAccessGrant"
      ],
      "credentialSubject": {
         "providedConsent": {
            "mode": [ "Read" ],
            "hasStatus": "ConsentStatusExplicitlyGiven",
            "isProvidedTo": "https://id.<ESS DOMAIN>/requestingrabbit"
          },
          "id": "https://id.<ESS DOMAIN>/owliverowner"
      }
   }
}

The filter’s verifiableCredential field contains the following non-empty fields for matching user-associated Access Grants:

type that matches an array that includes both "VerifiableCredential" and "SolidAccessGrant" as elements, AND
credentialSubject.providedConsent
- .mode that matches the value "Read", AND
- .hasStatus that matches the value "ConsentStatusExplicitlyGiven" , AND
- .isProvidedTo that matches the value "https://id.<ESS DOMAIN>/requestingrabbit" , AND
credentialSubject.id that matches the value "https://id.<ESS DOMAIN>/owliverowner" .

For owliverowner or requestingrabbit , the endpoint returns a VP with the matching Access Grants.

For other users, the endpoint returns a VP with no matching Access Grants.

Or the field matches an array that includes the specified values as elements.

Example 2

The following filter queries for user-associated Access Grants that gives Write access to the specified resource.

{
  "verifiableCredential": {
     "@context": [
       "https://www.w3.org/2018/credentials/v1",
       "https://schema.inrupt.com/credentials/v2.jsonld"
     ],
      "type": [
          "SolidAccessGrant"
     ],
     "credentialSubject": {
        "providedConsent": {
           "mode": "http://www.w3.org/ns/auth/acl#Write",
           "forPersonalData": [
             "https://storage.<ESS Domain>/<Root Container>/getting-started/readingList/myList"
           ]
        }
     }
  }
}

The filter’s verifiableCredential field contains the following non-empty fields for matching:

type that matches "SolidAccessGrant" value as an element, AND
credentialSubject.providedConsent
- .mode that matches the value "http://www.w3.org/ns/auth/acl#Write", AND
- .forPersonalData that matches the value "https://storage.<ESS Domain>/<Root Container>/getting-started/readingList/myList".

When the filter is posted to the /derive endpoint by either the resource owner of the reading list or by a user who has been granted access to that reading list:

For the resource owner, the endpoint returns a VVP with all the matching Access Grants given by the resource owner for that resource (regardless of the recipients).
For a user who is a recipient, the endpoint returns a VP with all the matching Access Grants given to the user for that resource.
For other users, the endpoint returns a VP with no matching Access Grants.

Upon completion, the endpoint returns a VP with the matching VCs.

Or the field matches an array that includes the specified values as elements.

Empty Filter Paths

ESS Access Grant service performs a match only on non-empty id, credentialSubject , issuer , and type field paths. Otherwise, the service returns all Access Requests/Grants associated with the user.

For example, when the following payloads are posted to the /derive endpoint:

The filter’s verifiableCredential field is an empty document; i.e., the filter VC does not contain any of the fields used for matching:
```
{
  "verifiableCredential": { }
}
```
This would match all Access Requests VCs and Access Grants VCs associated with the user.

The filter’s verifiableCredential contains type value of "VerifiableCredential" and empty values for the query field credentialSubject.hasConsent and no other filtering fields. As such, the filter VC does not have any non-empty matching filter paths

{
  "verifiableCredential": {
     "@context": [
       "https://www.w3.org/2018/credentials/v1",
       "https://schema.inrupt.com/credentials/v2.jsonld"
     ],
     "type": [
          "VerifiableCredential"
     ],
     "credentialSubject": {
       "hasConsent": { }
     }
  }
}

This would match all Access Requests VCs and Access Grants VCs associated with the user.

The filter’s verifiableCredential contains type value of "VerifiableCredential" and an empty values for the query field credentialSubject.providedConsent and no other filtering fields:

  {
    "verifiableCredential": {
       "@context": [
         "https://www.w3.org/2018/credentials/v1",
         "https://schema.inrupt.com/credentials/v2.jsonld",
         "https://w3id.org/security/data-integrity/v1",
         "https://w3id.org/vc-revocation-list-2020/v1",
         "https://w3id.org/vc/status-list/2021/v1",
         "https://w3id.org/security/suites/ed25519-2020/v1"
       ],
       "credentialStatus": {
         "id": "https://vc./status/VfaR#98",
         "revocationListCredential": "https://vc.<ESS DOMAIN>/status/VfaR",
         "revocationListIndex": "98",
         "type": "RevocationList2020Status"
       },
       "credentialSubject": {
         "providedConsent": { }
       },
       "type": [  "VerifiableCredential" ]
    }
  }

Upon completion, the endpoint returns a VP with the matching VCs; in this case, all Access Requests VCs and Access Grants VCs associated with the user.

The VC API specification is in Draft status. Features based on draft specifications are subject to change.

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