ResourceDiscovery: This patch adds a new resource discovery mechanism.

The intention is to allow for a way to advertise the existence of resources
at the OCM server.

Signed-off-by: Micke Nordin <kano@sunet.se>

Author: mickenordin

IETF-RFC.md

@@ -243,6 +243,7 @@ The JSON response body offered by the Discoverable Server SHOULD contain the fol
 * REQUIRED: apiVersion (string) - The OCM API version this endpoint supports. Example: `"1.2.0"`
 * REQUIRED: endPoint (string) - The URI of the OCM API available at this endpoint. Example: `"https://my-cloud-storage.org/ocm"`
 * OPTIONAL: provider (string) - A friendly branding name of this endpoint. Example: `"MyCloudStorage"`
+* OPTIONAL: resourceAdvertismentUri (string) - A URI that, if accessed, will advertise available resources at this endpoint.
 * REQUIRED: resourceTypes (array) - A list of all resource types this server supports in both the Sending Server role and the Receiving Server role, with their access protocols. Each item in this list should
 itself be an object containing the following fields:
   * name (string) -  A supported resource type (file, folder, calendar, contact, ...).
@@ -644,6 +645,83 @@ A third-party Directory Service is a back-end service used to federate multiple
   }
   ```
 
+# Appendix D: Resource Discovery Service
+
+An OCM Server MAY publicly advertise available resources. This is done via the `resourceAdvertismentUri`. It is expected to expose, via anonymous HTTP GET, a JSON document with the following format:
+
+  * REQUIRED: `server` - a human-readable name for the Servers providing the Resource Discovery Service
+  * REQUIRED: `resources` - a JSON array of objects to describe the list of OCM Servers with the following fields:
+    * OPTIONAL: `displayName` - the human-readable name of the OCM Server
+    * OPTIONAL: `publicUrl` - an public URL that can be used for direct download via anonymous HTTP GET
+    * OPTIONAL: `rocrate` - an embedded JSON object following the [ROCRATE](https://www.researchobject.org/ro-crate/specification/1.1/data-entities.html) data-entities specification.
+    * REQUIRED: `id` - the unique identifier of the resource at the OCM Server
+  Example:
+ ```json
+ {
+   "server": "OCM Server 1",
+   "resources": [
+     {
+       "publicUrl": "https://ocm-server-1.fqdn/s/1234567890abcdef",
+       "displayName": "Public Dataset 1",
+       "id": "1234567890abcdef",
+       "rocrate": {
+         "@context": "https://w3id.org/ro/crate/1.1/context",
+         "@graph": [
+           {
+             "@id": "ro-crate-metadata.json",
+             "@type": "CreativeWork",
+             "conformsTo": {
+               "@id": "https://w3id.org/ro/crate/1.1"
+             },
+             "about": {
+               "@id": "./"
+             }
+           },
+           {
+             "@id": "./",
+             "@type": "Dataset",
+             "name": "A RO-Crate embedded in OCM"
+           },
+           {
+             "@id": "https://ocm-server-1.fqdn/s/1234567890abcdef",
+             "@type": "File",
+             "name": "Public data file"
+           }
+         ]
+       }
+     },
+     {
+       "displayName": "Private Data Set 1",
+       "id": "0987654321fedcba",
+       "rocrate": {
+         "@context": "https://w3id.org/ro/crate/1.1/context",
+         "@graph": [
+           {
+             "@id": "ro-crate-metadata.json",
+             "@type": "CreativeWork",
+             "conformsTo": {
+               "@id": "https://w3id.org/ro/crate/1.1"
+             },
+             "about": {
+               "@id": "./"
+             }
+           },
+           {
+             "@id": "./",
+             "@type": "Dataset",
+             "name": "A RO-Crate embedded in OCM"
+           },
+           {
+             "@id": "0987654321fedcba",
+             "@type": "File",
+             "name": "Private data file"
+           }
+         ]
+       }
+     }
+   ]
+ }
+```
 
 # Acknowledgements
 

spec.yaml

@@ -342,6 +342,10 @@ components:
           type: string
           description: A friendly branding name of this endpoint
           example: MyCloudStorage
+        resourceadvertismenturi:
+          type: string
+          description: the uri of the ocm resources advertised at this endpoint
+          example: https://my-cloud-storage.org/ocm/resources
         resourceTypes:
           type: array
           description: |