Add post_hash_tags_max setting

app/lib/activitypub/activity/create.rb

@@ -142,7 +142,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
   end
 
   def valid_status?
-    !Admin::NgWord.reject?("#{@params[:spoiler_text]}\n#{@params[:text]}")
+    !Admin::NgWord.reject?("#{@params[:spoiler_text]}\n#{@params[:text]}") && !Admin::NgWord.hashtag_reject?(@tags.size)
   end
 
   def reply_to_local_account?

app/models/admin/ng_word.rb

@@ -6,10 +6,23 @@ class Admin::NgWord
       ng_words.any? { |word| text.include?(word) }
     end
 
+    def hashtag_reject?(hashtag_count)
+      post_hash_tags_max.positive? && post_hash_tags_max < hashtag_count
+    end
+
+    def hashtag_reject_with_extractor?(text)
+      hashtag_reject?(Extractor.extract_hashtags(text)&.size || 0)
+    end
+
     private
 
     def ng_words
       Setting.ng_words
     end
+
+    def post_hash_tags_max
+      value = Setting.post_hash_tags_max
+      value.is_a?(Integer) && value.positive? ? value : 0
+    end
   end
 end

app/models/form/admin_settings.rb

@@ -37,12 +37,14 @@ class Form::AdminSettings
     ng_words
     enable_block_emoji_reaction_settings
     hide_local_users_for_anonymous
+    post_hash_tags_max
   ).freeze
 
   INTEGER_KEYS = %i(
     media_cache_retention_period
     content_cache_retention_period
     backups_retention_period
+    post_hash_tags_max
   ).freeze
 
   BOOLEAN_KEYS = %i(

app/services/activitypub/process_status_update_service.rb

@@ -153,7 +153,7 @@ class ActivityPub::ProcessStatusUpdateService < BaseService
   end
 
   def valid_status?
-    !Admin::NgWord.reject?("#{@status_parser.spoiler_text}\n#{@status_parser.text}")
+    !Admin::NgWord.reject?("#{@status_parser.spoiler_text}\n#{@status_parser.text}") && !Admin::NgWord.hashtag_reject?(@tags.size)
   end
 
   def update_immediate_attributes!

app/services/post_status_service.rb

@@ -161,6 +161,7 @@ class PostStatusService < BaseService
 
   def validate_status!
     raise Mastodon::ValidationError, I18n.t('statuses.contains_ng_words') if Admin::NgWord.reject?("#{@options[:spoiler_text]}\n#{@options[:text]}")
+    raise Mastodon::ValidationError, I18n.t('statuses.too_many_hashtags') if Admin::NgWord.hashtag_reject_with_extractor?(@options[:text])
   end
 
   def validate_media!

app/services/update_status_service.rb

@@ -75,6 +75,7 @@ class UpdateStatusService < BaseService
 
   def validate_status!
     raise Mastodon::ValidationError, I18n.t('statuses.contains_ng_words') if Admin::NgWord.reject?("#{@options[:spoiler_text]}\n#{@options[:text]}")
+    raise Mastodon::ValidationError, I18n.t('statuses.too_many_hashtags') if Admin::NgWord.hashtag_reject_with_extractor?(@options[:text])
   end
 
   def validate_media!

app/views/admin/ng_words/show.html.haml

@@ -10,6 +10,9 @@
   .fields-group
     = f.input :ng_words, wrapper: :with_label, as: :text, input_html: { rows: 12 }, label: t('admin.ng_words.keywords')
 
+  .fields-group
+    = f.input :post_hash_tags_max, wrapper: :with_label, as: :integer, label: t('admin.ng_words.post_hash_tags_max')
+
   .fields-group
     = f.input :enable_block_emoji_reaction_settings, wrapper: :with_label, as: :boolean, label: t('admin.ng_words.enable_block_emoji_reaction_settings')