Return 400 when update request is invalid

slices/micropub/actions/posts/handle.rb

@@ -26,6 +26,8 @@ module Micropub
               res.status = 200
             in Failure[:not_permitted]
               halt 401
+            in Failure[:invalid_request]
+              halt 400
             end
           end
 

slices/micropub/commands/posts/update.rb

@@ -13,6 +13,8 @@ module Micropub
           post = post_repo.fetch!(slug)
 
           if params.key? :replace
+            return Failure(:invalid_request) 400 unless params[:replace].is_a?(Hash)
+
             content = params[:replace].delete(:content)
             content = content.is_a?(Array) ? content.first : content
             name = params[:replace].delete(:name)