Add "support" for Dendrite admin API (#502)

config.sample.yaml

@@ -73,16 +73,24 @@ database:
 # The configuration for the homeservers this media repository is known to control. Servers
 # not listed here will not be able to upload media.
 homeservers:
-  - name: example.org # This should match the server_name of your homeserver, and the Host header
-                      # provided to the media repo.
-    csApi: "https://example.org/" # The base URL to where the homeserver can actually be reached
-    backoffAt: 10 # The number of consecutive failures in calling this homeserver before the
-                  # media repository will start backing off. This defaults to 10 if not given.
-    adminApiKind: "matrix" # The kind of admin API the homeserver supports. If set to "matrix",
-                           # the media repo will use the Synapse-defined endpoints under the
-                           # unstable client-server API. When this is "synapse", the new /_synapse
-                           # endpoints will be used instead. Unknown values are treated as the
-                           # default, "matrix".
+  - # Keep the dash from this line.
+
+    # This should match the server_name of your homeserver, and the Host header
+    # provided to the media repo.
+    name: example.org
+
+    # The base URL to where the homeserver can actually be reached by MMR.
+    csApi: "https://example.org/"
+
+    # The number of consecutive failures in calling this homeserver before the
+    # media repository will start backing off. This defaults to 10 if not given.
+    backoffAt: 10
+
+    # The admin API interface supported by the homeserver. MMR uses a subset of the admin API
+    # during certain operations, like attempting to purge media from a room or validating server
+    # admin status. This should be set to one of "synapse", "dendrite", or "matrix". When set
+    # to "matrix", most functionality requiring the admin API will not work.
+    adminApiKind: "synapse"
 
 # Options for controlling how access tokens work with the media repo. It is recommended that if
 # you are going to use these options that the `/logout` and `/logout/all` client-server endpoints

matrix/requests_admin.go

@@ -18,8 +18,9 @@ func IsUserAdmin(ctx rcontext.RequestContext, serverName string, accessToken str
 	var replyError error
 	replyError = cb.CallContext(ctx, func() error {
 		response := &whoisResponse{}
+		// the whois endpoint is part of the spec, meaning we can avoid per-homeserver support
 		path := fmt.Sprintf("/_matrix/client/v3/admin/whois/%s", url.PathEscape(fakeUser))
-		if hs.AdminApiKind == "synapse" {
+		if hs.AdminApiKind == "synapse" { // synapse is special, dendrite is not
 			path = fmt.Sprintf("/_synapse/admin/v1/whois/%s", url.PathEscape(fakeUser))
 		}
 		urlStr := util.MakeUrl(hs.ClientServerApi, path)
@@ -46,6 +47,9 @@ func ListMedia(ctx rcontext.RequestContext, serverName string, accessToken strin
 		if hs.AdminApiKind == "synapse" {
 			path = fmt.Sprintf("/_synapse/admin/v1/room/%s/media", url.PathEscape(roomId))
 		}
+		if hs.AdminApiKind == "dendrite" {
+			return errors.New("this function is not supported when backed by Dendrite")
+		}
 		if path == "" {
 			return errors.New("unable to query media for homeserver: wrong or incompatible adminApiKind")
 		}