convert entity name to needed format for fetching

lib/diaspora_federation/federation/fetcher.rb

@@ -7,7 +7,9 @@ module DiasporaFederation
       # @param [Symbol, String] entity_type snake_case version of the entity class
       # @param [String] guid guid of the entity to fetch
       def self.fetch_public(author, entity_type, guid)
-        url = DiasporaFederation.callbacks.trigger(:fetch_person_url_to, author, "/fetch/#{entity_type}/#{guid}")
+        url = DiasporaFederation.callbacks.trigger(
+          :fetch_person_url_to, author, "/fetch/#{entity_name(entity_type)}/#{guid}"
+        )
         response = HttpClient.get(url)
         raise "Failed to fetch #{url}: #{response.status}" unless response.success?
 
@@ -18,6 +20,15 @@ module DiasporaFederation
         raise NotFetchable, "Failed to fetch #{entity_type}:#{guid} from #{author}: #{e.class}: #{e.message}"
       end
 
+      def self.entity_name(class_name)
+        return class_name if class_name =~ /^[a-z]*(_[a-z]*)*$/
+
+        raise DiasporaFederation::Entity::UnknownEntity, class_name unless Entities.const_defined?(class_name)
+
+        class_name.gsub(/(.)([A-Z])/, '\1_\2').downcase
+      end
+      private_class_method :entity_name
+
       # Raised, if the entity is not fetchable
       class NotFetchable < RuntimeError
       end

spec/lib/diaspora_federation/federation/fetcher_spec.rb

@@ -4,7 +4,7 @@ module DiasporaFederation
     let(:post_magic_env) { Salmon::MagicEnvelope.new(post, post.author).envelop(alice.private_key).to_xml }
 
     describe ".fetch_public" do
-      it "fetches a public post" do
+      it "fetches a public post with symbol as type param" do
         stub_request(:get, "https://example.org/fetch/post/#{post.guid}")
           .to_return(status: 200, body: post_magic_env)
 
@@ -27,6 +27,29 @@ module DiasporaFederation
         Federation::Fetcher.fetch_public(post.author, :post, post.guid)
       end
 
+      it "fetches a public post with class name as type param" do
+        stub_request(:get, "https://example.org/fetch/post/#{post.guid}")
+          .to_return(status: 200, body: post_magic_env)
+
+        expect_callback(:fetch_person_url_to, post.author, "/fetch/post/#{post.guid}")
+          .and_return("https://example.org/fetch/post/#{post.guid}")
+        expect_callback(:fetch_public_key, post.author).and_return(alice.public_key)
+
+        receiver = double
+        expect(Federation::Receiver::Public).to receive(:new).with(
+          kind_of(Salmon::MagicEnvelope)
+        ) do |magic_env|
+          expect(magic_env.payload.guid).to eq(post.guid)
+          expect(magic_env.payload.author).to eq(post.author)
+          expect(magic_env.payload.raw_message).to eq(post.raw_message)
+          expect(magic_env.payload.public).to eq("true")
+          receiver
+        end
+        expect(receiver).to receive(:receive)
+
+        Federation::Fetcher.fetch_public(post.author, "Post", post.guid)
+      end
+
       it "follows redirects" do
         stub_request(:get, "https://example.org/fetch/post/#{post.guid}")
           .to_return(status: 302, headers: {"Location" => "https://example.com/fetch/post/#{post.guid}"})