1 files changed, 24 insertions, 10 deletions
diff --git a/app/services/activitypub/fetch_remote_key_service.rb b/app/services/activitypub/fetch_remote_key_service.rb
index c48288b3b..01008d883 100644
--- a/app/services/activitypub/fetch_remote_key_service.rb
+++ b/app/services/activitypub/fetch_remote_key_service.rb
@@ -3,9 +3,11 @@
 class ActivityPub::FetchRemoteKeyService < BaseService
   include JsonLdHelper
 
+  class Error < StandardError; end
+
   # Returns account that owns the key
-  def call(uri, id: true, prefetched_body: nil)
-    return if uri.blank?
+  def call(uri, id: true, prefetched_body: nil, suppress_errors: true)
+    raise Error, 'No key URI given' if uri.blank?
 
     if prefetched_body.nil?
       if id
@@ -13,7 +15,7 @@ class ActivityPub::FetchRemoteKeyService < BaseService
         if person?
           @json = fetch_resource(@json['id'], true)
         elsif uri != @json['id']
-          return
+          raise Error, "Fetched URI #{uri} has wrong id #{@json['id']}"
         end
       else
         @json = fetch_resource(uri, id)
@@ -22,21 +24,29 @@ class ActivityPub::FetchRemoteKeyService < BaseService
       @json = body_to_json(prefetched_body, compare_id: id ? uri : nil)
     end
 
-    return unless supported_context?(@json) && expected_type?
-    return find_account(@json['id'], @json) if person?
+    raise Error, "Unable to fetch key JSON at #{uri}" if @json.nil?
+    raise Error, "Unsupported JSON-LD context for document #{uri}" unless supported_context?(@json)
+    raise Error, "Unexpected object type for key #{uri}" unless expected_type?
+    return find_account(@json['id'], @json, suppress_errors) if person?
 
     @owner = fetch_resource(owner_uri, true)
 
-    return unless supported_context?(@owner) && confirmed_owner?
+    raise Error, "Unable to fetch actor JSON #{owner_uri}" if @owner.nil?
+    raise Error, "Unsupported JSON-LD context for document #{owner_uri}" unless supported_context?(@owner)
+    raise Error, "Unexpected object type for actor #{owner_uri} (expected any of: #{SUPPORTED_TYPES})" unless expected_owner_type?
+    raise Error, "publicKey id for #{owner_uri} does not correspond to #{@json['id']}" unless confirmed_owner?
 
-    find_account(owner_uri, @owner)
+    find_account(owner_uri, @owner, suppress_errors)
+  rescue Error => e
+    Rails.logger.debug "Fetching key #{uri} failed: #{e.message}"
+    raise unless suppress_errors
   end
 
   private
 
-  def find_account(uri, prefetched_body)
+  def find_account(uri, prefetched_body, suppress_errors)
     account   = ActivityPub::TagManager.instance.uri_to_resource(uri, Account)
-    account ||= ActivityPub::FetchRemoteAccountService.new.call(uri, prefetched_body: prefetched_body)
+    account ||= ActivityPub::FetchRemoteAccountService.new.call(uri, prefetched_body: prefetched_body, suppress_errors: suppress_errors)
     account
   end
 
@@ -56,7 +66,11 @@ class ActivityPub::FetchRemoteKeyService < BaseService
     @owner_uri ||= value_or_id(@json['owner'])
   end
 
+  def expected_owner_type?
+    equals_or_includes_any?(@owner['type'], ActivityPub::FetchRemoteAccountService::SUPPORTED_TYPES)
+  end
+
   def confirmed_owner?
-    equals_or_includes_any?(@owner['type'], ActivityPub::FetchRemoteAccountService::SUPPORTED_TYPES) && value_or_id(@owner['publicKey']) == @json['id']
+    value_or_id(@owner['publicKey']) == @json['id']
   end
 end