backend/app/controllers/application_controller.rb

@@ -11,4 +11,15 @@ class ApplicationController < ActionController::API
     code = request.headers['X-Transfer-Code'] || request.headers['HTTP_X_TRANSFER_CODE']
     @current_user = User.find_by(inheritance_code: code)
   end
+
+  def bool? key, default: false
+    return default if params[key].nil?
+
+    s = params[key].to_s.strip.downcase
+    if default
+      !(s.in?(['0', 'false', 'off', 'no']))
+    else
+      s.in?(['', '1', 'true', 'on', 'yes'])
+    end
+  end
 end

backend/app/controllers/tags_controller.rb

@@ -16,7 +16,8 @@ class TagsController < ApplicationController
     q = params[:q].to_s.strip
     return render json: [] if q.blank?
 
-    with_nico = !(params[:nico].to_s.strip.downcase.in?(['0', 'false', 'off', 'no']))
+    with_nico = bool?(:nico, default: true)
+    present_only = bool?(:present, default: true)
 
     alias_rows =
         TagName
@@ -33,6 +34,7 @@ class TagsController < ApplicationController
     end
 
     base = Tag.joins(:tag_name).includes(:tag_name)
+    base = base.where('tags.post_count > 0') if present_only
 
     canonical_hit =
         base

backend/spec/requests/tags_spec.rb

@@ -4,8 +4,12 @@ require 'rails_helper'
 
 RSpec.describe 'Tags API', type: :request do
   let!(:tn) { TagName.create!(name: 'spec_tag') }
-  let!(:tag) { Tag.create!(tag_name: tn, category: 'general') }
+  let!(:tag) { Tag.create!(tag_name: tn, category: :general) }
   let!(:alias_tn) { TagName.create!(name: 'unko', canonical: tn) }
+  let!(:post) { Post.create!(url: 'https://example.com/unkounkounko') }
+  let!(:post_tag) { PostTag.create!(post:, tag:) }
+  let!(:tn2) { TagName.create!(name: 'unknown') }
+  let!(:tag2) { Tag.create!(tag_name: tn2, category: :general) }
 
   describe 'GET /tags' do
     it 'returns tags with name' do
@@ -71,6 +75,7 @@ RSpec.describe 'Tags API', type: :request do
       expect(json.map { |t| t['name'] }).to include('spec_tag')
       t = json.find { |t| t['name'] == 'spec_tag' }
       expect(t['matched_alias']).to eq('unko')
+      expect(json.map { |t| t['name'] }).not_to include('unknown')
     end
   end