Support "_" placeholder username for domain's own NIP-05

app/controllers/well_known_controller.rb

@@ -1,18 +1,23 @@
 class WellKnownController < ApplicationController
+  before_action :require_nostr_enabled, only: [ :nostr ]
+
   def nostr
     http_status :unprocessable_entity and return if params[:name].blank?
     domain = request.headers["X-Forwarded-Host"].presence || Setting.primary_domain
-    @user = User.where(cn: params[:name], ou: domain).first
-    http_status :not_found and return if @user.nil? || @user.nostr_pubkey.blank?
+    relay_url = Setting.nostr_relay_url
 
-    res = {
-      names: { @user.cn => @user.nostr_pubkey }
-    }
+    if params[:name] == "_"
+      # pubkey for the primary domain without a username (e.g. kosmos.org)
+      res = { names: { "_": Setting.nostr_public_key } }
+    else
+      @user = User.where(cn: params[:name], ou: domain).first
+      http_status :not_found and return if @user.nil? || @user.nostr_pubkey.blank?
 
-    if Setting.nostr_relay_url
-      res[:relays] = {
-        @user.nostr_pubkey => [ Setting.nostr_relay_url ]
-      }
+      res = { names: { @user.cn => @user.nostr_pubkey } }
+    end
+
+    if relay_url
+      res[:relays] = { @user.nostr_pubkey => [ relay_url ] }
     end
 
     respond_to do |format|
@@ -21,4 +26,10 @@ class WellKnownController < ApplicationController
       end
     end
   end
+
+  private
+
+    def require_nostr_enabled
+      http_status :not_found unless Setting.nostr_enabled?
+    end
 end