diff --git a/lib/diaspora/federation/entities.rb b/lib/diaspora/federation/entities.rb
index 48b07c43b..0165724fe 100644
--- a/lib/diaspora/federation/entities.rb
+++ b/lib/diaspora/federation/entities.rb
@@ -2,7 +2,7 @@ module Diaspora
   module Federation
     module Entities
       def self.build(entity)
-        public_send(Mappings.builder_for(entity.class), entity)
+        public_send(Mappings.builder_for(entity), entity)
       end
 
       def self.post(post)
diff --git a/lib/diaspora/federation/mappings.rb b/lib/diaspora/federation/mappings.rb
index 0d19af545..086df4685 100644
--- a/lib/diaspora/federation/mappings.rb
+++ b/lib/diaspora/federation/mappings.rb
@@ -1,82 +1,80 @@
 module Diaspora
   module Federation
     module Mappings
+      # rubocop:disable Metrics/CyclomaticComplexity
+
       # used in Diaspora::Federation::Receive
-      def self.receiver_for(federation_class)
-        fetch_from(ENTITY_RECEIVERS, federation_class)
+      def self.receiver_for(federation_entity)
+        case federation_entity
+        when DiasporaFederation::Entities::Comment           then :comment
+        when DiasporaFederation::Entities::Contact           then :contact
+        when DiasporaFederation::Entities::Conversation      then :conversation
+        when DiasporaFederation::Entities::Like              then :like
+        when DiasporaFederation::Entities::Message           then :message
+        when DiasporaFederation::Entities::Participation     then :participation
+        when DiasporaFederation::Entities::Photo             then :photo
+        when DiasporaFederation::Entities::PollParticipation then :poll_participation
+        when DiasporaFederation::Entities::Profile           then :profile
+        when DiasporaFederation::Entities::Reshare           then :reshare
+        when DiasporaFederation::Entities::StatusMessage     then :status_message
+        else not_found(federation_entity.class)
+        end
       end
 
       # used in Diaspora::Federation::Entities
-      def self.builder_for(diaspora_class)
-        fetch_from(ENTITY_BUILDERS, diaspora_class)
+      def self.builder_for(diaspora_entity)
+        case diaspora_entity
+        when AccountDeletion   then :account_deletion
+        when Comment           then :comment
+        when Contact           then :contact
+        when Conversation      then :conversation
+        when Like              then :like
+        when Message           then :message
+        when Participation     then :participation
+        when Photo             then :photo
+        when PollParticipation then :poll_participation
+        when Profile           then :profile
+        when Reshare           then :reshare
+        when Retraction        then :retraction
+        when ContactRetraction then :retraction
+        when StatusMessage     then :status_message
+        else not_found(diaspora_entity.class)
+        end
       end
 
       def self.model_class_for(entity_name)
-        fetch_from(ENTITY_MODELS, entity_name)
+        case entity_name
+        when "Comment"           then Comment
+        when "Conversation"      then Conversation
+        when "Like"              then Like
+        when "Participation"     then Participation
+        when "PollParticipation" then PollParticipation
+        when "Photo"             then Photo
+        when "Poll"              then Poll
+        when "Post"              then Post
+        when "Person"            then Person # TODO: deprecated
+        when "Reshare"           then Post
+        when "StatusMessage"     then Post
+        else not_found(entity_name)
+        end
       end
 
       def self.entity_name_for(model)
-        fetch_from(ENTITY_NAMES, model.class.base_class)
+        case model
+        when Comment           then "Comment"
+        when Like              then "Like"
+        when Participation     then "Participation"
+        when PollParticipation then "PollParticipation"
+        when Photo             then "Photo"
+        when Post              then "Post"
+        else not_found(model.class)
+        end
       end
+      # rubocop:enable Metrics/CyclomaticComplexity
 
-      private_class_method def self.fetch_from(mapping, key)
-        mapping.fetch(key) { raise DiasporaFederation::Entity::UnknownEntity, "unknown entity: #{key}" }
+      private_class_method def self.not_found(key)
+        raise DiasporaFederation::Entity::UnknownEntity, "unknown entity: #{key}"
       end
-
-      ENTITY_RECEIVERS = {
-        DiasporaFederation::Entities::Comment           => :comment,
-        DiasporaFederation::Entities::Contact           => :contact,
-        DiasporaFederation::Entities::Conversation      => :conversation,
-        DiasporaFederation::Entities::Like              => :like,
-        DiasporaFederation::Entities::Message           => :message,
-        DiasporaFederation::Entities::Participation     => :participation,
-        DiasporaFederation::Entities::Photo             => :photo,
-        DiasporaFederation::Entities::PollParticipation => :poll_participation,
-        DiasporaFederation::Entities::Profile           => :profile,
-        DiasporaFederation::Entities::Reshare           => :reshare,
-        DiasporaFederation::Entities::StatusMessage     => :status_message
-      }.freeze
-
-      ENTITY_BUILDERS = {
-        AccountDeletion   => :account_deletion,
-        Comment           => :comment,
-        Contact           => :contact,
-        Conversation      => :conversation,
-        Like              => :like,
-        Message           => :message,
-        Participation     => :participation,
-        Photo             => :photo,
-        PollParticipation => :poll_participation,
-        Profile           => :profile,
-        Reshare           => :reshare,
-        Retraction        => :retraction,
-        ContactRetraction => :retraction,
-        StatusMessage     => :status_message
-      }.freeze
-
-      ENTITY_MODELS = {
-        "Comment"           => Comment,
-        "Conversation"      => Conversation,
-        "Like"              => Like,
-        "Participation"     => Participation,
-        "PollParticipation" => PollParticipation,
-        "Photo"             => Photo,
-        "Poll"              => Poll,
-        "Post"              => Post,
-        # TODO: deprecated
-        "Person"            => Person,
-        "Reshare"           => Post,
-        "StatusMessage"     => Post
-      }.freeze
-
-      ENTITY_NAMES = {
-        Comment           => "Comment",
-        Like              => "Like",
-        Participation     => "Participation",
-        PollParticipation => "PollParticipation",
-        Photo             => "Photo",
-        Post              => "Post"
-      }.freeze
     end
   end
 end
diff --git a/lib/diaspora/federation/receive.rb b/lib/diaspora/federation/receive.rb
index d4dee7648..a3e8cadd4 100644
--- a/lib/diaspora/federation/receive.rb
+++ b/lib/diaspora/federation/receive.rb
@@ -4,7 +4,7 @@ module Diaspora
       extend Diaspora::Logging
 
       def self.perform(entity)
-        public_send(Mappings.receiver_for(entity.class), entity)
+        public_send(Mappings.receiver_for(entity), entity)
       end
 
       def self.account_deletion(entity)