ResourceDiscovery: This patch adds a new resource discovery mechanism.

IETF-RFC.md

@@ -511,6 +511,8 @@ contain the following information about its OCM API:
   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
@@ -1171,15 +1173,15 @@ format:
   Servers exposed by the Directory Service
 * REQUIRED: `servers` - a JSON array of objects to describe the list
   of OCM Servers with the following string fields:
-  - REQUIRED: `url` - an absolute URL identifying the
+  * REQUIRED: `url` - an absolute URL identifying the
     OCM Server.  It MUST:
-    - include scheme: either `https://` or
+    * include scheme: either `https://` or
       (for testing purposes) `http://`
-    - include host (either a FQDN or an IP address)
-    - MAY include a non-default port
-    - MUST NOT include a base path (e.g., `/ocm`)
-    - MUST NOT include userinfo, query, or fragment
-  - REQUIRED: `displayName` - a human-readable name
+    * include host (either a FQDN or an IP address)
+    * MAY include a non-default port
+    * MUST NOT include a base path (e.g., `/ocm`)
+    * MUST NOT include userinfo, query, or fragment
+  * REQUIRED: `displayName` - a human-readable name
     for the OCM Server
     Example:
 
@@ -1203,6 +1205,94 @@ format:
 }
 ```
 
+# 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: `providerId` - 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
 
 Our deepest thanks and appreciation go to the people who started the

spec.yaml

@@ -336,6 +336,10 @@ 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: |