#34

backend/app/controllers/user_settings_controller.rb

@@ -0,0 +1,56 @@
+class UserSettingsController < ApplicationController
+  def show
+    return head :unauthorized unless current_user
+
+    render json: current_setting.serializable_hash
+  end
+
+  def update
+    return head :unauthorized unless current_user
+
+    raw_attributes = request.request_parameters
+    field_errors = validate_raw_attributes(raw_attributes)
+    return render_validation_error fields: field_errors if field_errors.present?
+
+    setting = current_setting
+    setting.assign_attributes(raw_attributes.slice(*Setting::EDITABLE_ATTRIBUTES))
+
+    if setting.save
+      render json: setting.serializable_hash, status: :ok
+    else
+      render_validation_error setting
+    end
+  end
+
+  private
+
+  def current_setting
+    current_user.setting || current_user.create_setting!(Setting.defaults)
+  end
+
+  def validate_raw_attributes raw_attributes
+    raw_attributes.each_with_object({ }) do |(key, value), errors|
+      unless Setting::EDITABLE_ATTRIBUTES.include?(key)
+        errors[key.to_sym] = ['不明な設定です．']
+        next
+      end
+
+      next if value_matches_type?(key, value)
+
+      errors[key.to_sym] = ['値の型が不正です．']
+    end
+  end
+
+  def value_matches_type? key, value
+    case Setting::TYPE_BY_ATTRIBUTE.fetch(key)
+    when :string
+      value.is_a?(String)
+    when :integer
+      value.is_a?(Integer)
+    when :boolean
+      value == true || value == false
+    else
+      false
+    end
+  end
+end

backend/app/models/setting.rb

@@ -1,7 +1,87 @@
 class Setting < ApplicationRecord
+  THEMES = ['system', 'light', 'dark'].freeze
+  DISPLAY_DENSITIES = ['comfortable', 'compact'].freeze
+  FONT_SIZES = ['small', 'normal', 'large'].freeze
+  POST_LIST_LIMITS = [20, 50, 100].freeze
+  POST_LIST_ORDERS = [
+    'title_asc',
+    'title_desc',
+    'url_asc',
+    'url_desc',
+    'original_created_at_asc',
+    'original_created_at_desc',
+    'created_at_asc',
+    'created_at_desc',
+    'updated_at_asc',
+    'updated_at_desc',
+  ].freeze
+  VIEWED_POST_DISPLAYS = ['show', 'dim', 'hide'].freeze
+  AUTO_FETCH_MODES = ['auto', 'manual', 'off'].freeze
+  WIKI_EDITOR_MODES = ['split', 'write', 'preview'].freeze
+
+  STRING_ATTRIBUTES = [
+    'theme',
+    'display_density',
+    'font_size',
+    'post_list_order',
+    'viewed_post_display',
+    'auto_fetch_title',
+    'auto_fetch_thumbnail',
+    'wiki_editor_mode',
+  ].freeze
+  INTEGER_ATTRIBUTES = ['post_list_limit'].freeze
+  BOOLEAN_ATTRIBUTES = ['tag_autocomplete_nico'].freeze
+  EDITABLE_ATTRIBUTES =
+      (STRING_ATTRIBUTES + INTEGER_ATTRIBUTES + BOOLEAN_ATTRIBUTES).freeze
+  TYPE_BY_ATTRIBUTE = {
+    'theme' => :string,
+    'display_density' => :string,
+    'font_size' => :string,
+    'post_list_limit' => :integer,
+    'post_list_order' => :string,
+    'viewed_post_display' => :string,
+    'tag_autocomplete_nico' => :boolean,
+    'auto_fetch_title' => :string,
+    'auto_fetch_thumbnail' => :string,
+    'wiki_editor_mode' => :string,
+  }.freeze
+
   belongs_to :user
 
   validates :user_id, presence: true
-  validates :key, presence: true, length: { maximum: 255 }
-  validates :value, presence: true
+  validates :user_id, uniqueness: true
+
+  validates :theme, inclusion: { in: THEMES }
+  validates :display_density, inclusion: { in: DISPLAY_DENSITIES }
+  validates :font_size, inclusion: { in: FONT_SIZES }
+  validates :post_list_limit, inclusion: { in: POST_LIST_LIMITS }
+  validates :post_list_order, inclusion: { in: POST_LIST_ORDERS }
+  validates :viewed_post_display, inclusion: { in: VIEWED_POST_DISPLAYS }
+  validates :tag_autocomplete_nico, inclusion: { in: [true, false] }
+  validates :auto_fetch_title, inclusion: { in: AUTO_FETCH_MODES }
+  validates :auto_fetch_thumbnail, inclusion: { in: AUTO_FETCH_MODES }
+  validates :wiki_editor_mode, inclusion: { in: WIKI_EDITOR_MODES }
+
+  def self.defaults
+    {
+      theme: 'system',
+      display_density: 'comfortable',
+      font_size: 'normal',
+      post_list_limit: 50,
+      post_list_order: 'created_at_desc',
+      viewed_post_display: 'show',
+      tag_autocomplete_nico: true,
+      auto_fetch_title: 'manual',
+      auto_fetch_thumbnail: 'manual',
+      wiki_editor_mode: 'split',
+    }
+  end
+
+  def self.serializable_attributes
+    EDITABLE_ATTRIBUTES.map(&:to_sym)
+  end
+
+  def serializable_hash(options = nil)
+    super({ only: self.class.serializable_attributes }.merge(options || { }))
+  end
 end

backend/app/models/user.rb

@@ -7,7 +7,7 @@ class User < ApplicationRecord
 
   has_many :created_posts,
            class_name: 'Post', foreign_key: :uploaded_user_id, dependent: :nullify
-  has_many :settings
+  has_one :setting, dependent: :destroy
   has_many :user_ips, dependent: :destroy
   has_many :ip_addresses, through: :user_ips
   has_many :user_post_views, dependent: :destroy

backend/config/routes.rb

@@ -89,6 +89,11 @@ Rails.application.routes.draw do
     end
   end
 
+  scope 'users/settings', controller: :user_settings do
+    get '', action: :show
+    patch '', action: :update
+  end
+
   resources :deerjikists, only: [] do
     collection do
       scope ':platform/:code' do

backend/db/migrate/20260704000000_rebuild_settings_as_typed_user_settings.rb

@@ -0,0 +1,53 @@
+class RebuildSettingsAsTypedUserSettings < ActiveRecord::Migration[8.0]
+  def change
+    remove_foreign_key :settings, :users if foreign_key_exists?(:settings, :users)
+    remove_index :settings, :user_id if index_exists?(:settings, :user_id)
+
+    remove_column :settings, :key, :string if column_exists?(:settings, :key)
+    remove_column :settings, :value, :json if column_exists?(:settings, :value)
+
+    change_column_null :settings, :user_id, false
+
+    add_column :settings, :theme, :string, null: false, default: 'system'
+    add_column :settings,
+               :display_density,
+               :string,
+               null: false,
+               default: 'comfortable'
+    add_column :settings, :font_size, :string, null: false, default: 'normal'
+    add_column :settings, :post_list_limit, :integer, null: false, default: 50
+    add_column :settings,
+               :post_list_order,
+               :string,
+               null: false,
+               default: 'created_at_desc'
+    add_column :settings,
+               :viewed_post_display,
+               :string,
+               null: false,
+               default: 'show'
+    add_column :settings,
+               :tag_autocomplete_nico,
+               :boolean,
+               null: false,
+               default: true
+    add_column :settings,
+               :auto_fetch_title,
+               :string,
+               null: false,
+               default: 'manual'
+    add_column :settings,
+               :auto_fetch_thumbnail,
+               :string,
+               null: false,
+               default: 'manual'
+    add_column :settings,
+               :wiki_editor_mode,
+               :string,
+               null: false,
+               default: 'split'
+
+    add_index :settings, :user_id, unique: true
+    add_foreign_key :settings, :users
+  end
+end

backend/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_06_26_010000) do
+ActiveRecord::Schema[8.0].define(version: 2026_07_04_000000) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -374,11 +374,19 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_26_010000) do
 
   create_table "settings", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "user_id", null: false
-    t.string "key", null: false
-    t.json "value", null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
-    t.index ["user_id"], name: "index_settings_on_user_id"
+    t.string "theme", default: "system", null: false
+    t.string "display_density", default: "comfortable", null: false
+    t.string "font_size", default: "normal", null: false
+    t.integer "post_list_limit", default: 50, null: false
+    t.string "post_list_order", default: "created_at_desc", null: false
+    t.string "viewed_post_display", default: "show", null: false
+    t.boolean "tag_autocomplete_nico", default: true, null: false
+    t.string "auto_fetch_title", default: "manual", null: false
+    t.string "auto_fetch_thumbnail", default: "manual", null: false
+    t.string "wiki_editor_mode", default: "split", null: false
+    t.index ["user_id"], name: "index_settings_on_user_id", unique: true
   end
 
   create_table "tag_implications", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|