#428

backend/app/controllers/application_controller.rb

@@ -1,4 +1,7 @@
 class ApplicationController < ActionController::API
+  include ActionController::Cookies
+  include ActionController::RequestForgeryProtection
+
   class UnsupportedLocale < StandardError
     ;
   end
@@ -11,18 +14,39 @@ class ApplicationController < ActionController::API
   before_action :authenticate_user
   before_action :reject_banned_user!
   before_action :validate_explicit_locale!
+  protect_from_forgery with: :exception
+  self.forgery_protection_origin_check = true
+  rescue_from ActionController::InvalidAuthenticityToken, with: :reject_invalid_csrf
+  after_action :prevent_authenticated_caching
 
   def current_user = @current_user
 
   private
 
+  def reject_invalid_csrf
+    response.headers['X-CSRF-Invalid'] = '1'
+    response.headers['Cache-Control'] = 'private, no-store'
+    head :forbidden
+  end
+
   def authenticate_user
-    code = request.headers['X-Transfer-Code'] || request.headers['HTTP_X_TRANSFER_CODE']
+    code = session[:inheritance_code]
     return if code.blank?
 
     @current_user = User.find_by(inheritance_code: code)
   end
 
+  def prevent_authenticated_caching
+    response.headers['Cache-Control'] = 'private, no-store' if current_user
+  end
+
+  def establish_user_session user
+    reset_session
+    session[:inheritance_code] = user.inheritance_code
+    @current_user = user
+    response.headers['Cache-Control'] = 'private, no-store'
+  end
+
   def bool? key, default: false
     return default if params[key].nil?
 

backend/app/controllers/nico_tags_controller.rb

@@ -24,7 +24,7 @@ class NicoTagsController < ApplicationController
 
     q =
         ExternalTag
-        .joins("LEFT JOIN (#{ post_tag_max_sql }) post_tag_max " \
+        .joins("LEFT JOIN (#{ post_tag_max_sql }) post_tag_max " +
                'ON post_tag_max.external_tag_id = external_tags.id')
         .includes(linked_tags: [:tag_names, :tag_descriptions])
     if name
@@ -37,7 +37,7 @@ class NicoTagsController < ApplicationController
       linked_tag_ids =
           Tag
           .joins(:tag_names)
-          .where(tag_names: { language_code: 'ja', primary_flg: true })
+          .where(tag_names: { language_code: locale.language_code, primary_flg: true })
           .where('tag_names.name LIKE ?', "%#{ linked_tag }%")
           .pluck(:id)
       linked_nico_tag_ids = NicoTagRelation.where(tag_id: linked_tag_ids).pluck(:nico_tag_id)
@@ -45,7 +45,7 @@ class NicoTagsController < ApplicationController
     end
     if link_status.in?(['linked', 'unlinked'])
       exists_sql =
-          'EXISTS (SELECT 1 FROM nico_tag_relations ' \
+          'EXISTS (SELECT 1 FROM nico_tag_relations ' +
           'WHERE nico_tag_relations.nico_tag_id = external_tags.id)'
       q = link_status == 'linked' ? q.where(exists_sql) : q.where("NOT #{ exists_sql }")
     end

backend/app/controllers/posts_controller.rb

@@ -400,8 +400,76 @@ class PostsController < ApplicationController
     render_post_form_record_invalid e.record
   end
 
+  def tag_filters
+    source = resolve_locale!
+    code = params[:target_locale]
+    return head :not_found unless code.is_a?(String) && Locale.codes.value?(code)
+
+    target = Locale.find_by(code:, deprecated_at: nil)
+    return head :not_found unless target
+
+    literals = params[:tags].to_s.split
+    references = tag_filter_references(literals)
+    names = literals.each_with_index.map do |literal, index|
+      reference = references&.[](index)
+      (reference && reference['negative'] == false) ? literal : literal.sub(/\Anot:/i, '')
+    end
+    internal = references ? {} : TagName.where(
+        language_code: source.language_code, name: names).pluck(:name, :tag_id).to_h
+    canonical = references ? {} : TagName.where(
+        language_code: source.language_code, primary_flg: true,
+        tag_id: internal.values).pluck(:tag_id, :name).to_h
+    external_names = names.map { canonical[internal[_1]] || _1 }
+    external = references ? {} : ExternalTag.where(
+        "CONCAT(platform, ':', name) IN (?)", external_names).pluck(
+        Arel.sql("CONCAT(platform, ':', name)"), :id).to_h
+    ids = references ? references.filter_map { _1['tag_id'] } : internal.values
+    translated = TagName.where(language_code: target.language_code,
+                               primary_flg: true, tag_id: ids).pluck(:tag_id, :name).to_h
+
+    filters = literals.each_with_index.map do |literal, index|
+      name = names[index]
+      reference = if references
+                    references[index].except('name')
+                  else
+                    matches = {}
+                    matches['tag_id'] = internal[name] if internal[name]
+                    external_id = external[external_names[index]]
+                    matches['external_tag_id'] = external_id if external_id
+                    matches.empty? ? { 'missing' => true } : matches
+                  end
+      name = translated[reference['tag_id']] || name
+      negative = reference.fetch('negative', literal.downcase.start_with?('not:'))
+      prefix = negative ? literal[/\Anot:/i] || 'not:' : ''
+      reference.merge('name' => "#{ prefix }#{ name }", 'negative' => negative)
+    end
+    render json: { references: filters }
+  end
+
   private
 
+  def tag_filter_references literals
+    raw = params[:tag_refs]
+    return nil if raw.blank?
+
+    references = JSON.parse(raw)
+    valid = references.is_a?(Array) && references.all? do |reference|
+      next false unless reference.is_a?(Hash) && reference['name'].is_a?(String)
+
+      ids = [reference['tag_id'], reference['external_tag_id']].compact
+      ((ids.any? || reference['missing'] == true) &&
+          ids.all? { _1.is_a?(Integer) && _1.positive? } &&
+          (!reference.key?('missing') || (reference['missing'] == true && ids.empty?)) &&
+          (!reference.key?('negative') || [true, false].include?(reference['negative'])))
+    end
+    raise ActionController::BadRequest unless valid
+    return nil unless references.map { _1['name'] } == literals
+
+    references
+  rescue JSON::ParserError, TypeError
+    raise ActionController::BadRequest
+  end
+
   def filtered_posts locale
     tag_names = params[:tags].to_s.split
     match_type = params[:match]
@@ -413,20 +481,29 @@ class PostsController < ApplicationController
   end
 
   def filter_posts_by_tags locale, tag_names, match_type
-    literals = tag_names.map do |raw_name|
-      { name: TagName.canonicalise(locale, raw_name.sub(/\Anot:/i, '')).first,
-        negative: raw_name.downcase.start_with?('not:') }
+    references = tag_filter_references(tag_names)
+    literals = tag_names.each_with_index.map do |raw_name, index|
+      name = raw_name.sub(/\Anot:/i, '')
+      name = TagName.canonicalise(locale, name).first unless references
+      reference = references&.[](index)
+      negative = if reference&.key?('negative')
+                   reference['negative']
+                 else
+                   raw_name.downcase.start_with?('not:')
+                 end
+      { name:, negative:, reference: }
     end
 
     return Post.all if literals.empty?
 
     if match_type == 'any'
       literals.reduce(Post.none) do |posts, literal|
-        posts.or(tag_literal_relation(locale, literal[:name], negative: literal[:negative]))
+        posts.or(tag_literal_relation(locale, literal[:name], negative: literal[:negative],
+                                      reference: literal[:reference]))
       end
     else
       literals.reduce(Post.all) do |posts, literal|
-        ids = tagged_post_ids_for(locale, literal[:name])
+        ids = tagged_post_ids_for(locale, literal[:name], reference: literal[:reference])
         if literal[:negative]
           posts.where.not(id: ids)
         else
@@ -436,8 +513,8 @@ class PostsController < ApplicationController
     end
   end
 
-  def tag_literal_relation locale, name, negative:
-    ids = tagged_post_ids_for(locale, name)
+  def tag_literal_relation locale, name, negative:, reference: nil
+    ids = tagged_post_ids_for(locale, name, reference:)
     if negative
       Post.where.not(id: ids)
     else
@@ -445,7 +522,20 @@ class PostsController < ApplicationController
     end
   end
 
-  def tagged_post_ids_for locale, name
+  def tagged_post_ids_for locale, name, reference: nil
+    if reference
+      matches = Post.none
+      if reference['tag_id']
+        matches = matches.or(Post.where(id: PostTag.where(
+            tag_id: reference['tag_id']).select(:post_id)))
+      end
+      if reference['external_tag_id']
+        matches = matches.or(Post.where(id: PostExternalTag.where(
+            external_tag_id: reference['external_tag_id']).select(:post_id)))
+      end
+      return matches.select(:id)
+    end
+
     posts_by_internal_tags =
         Post
         .joins(tags: :tag_names)

backend/app/controllers/tags_controller.rb

@@ -307,7 +307,7 @@ class TagsController < ApplicationController
         .joins(:tag_names)
         .preload(:tag_names, :materials, :deerjikists, :tag_descriptions,
                  parents: [:tag_names, :materials, :deerjikists, :tag_descriptions])
-        .find_by(tag_names: { name:, language_code: locale.language_code, primary_flg: true })
+        .find_by(tag_names: { name:, language_code: locale.language_code })
     return render json: TagRepr.base(tag, language_code: locale.language_code) if tag
 
     platform, external_name = name.split(':', 2)

backend/app/controllers/users_controller.rb

@@ -1,45 +1,69 @@
 class UsersController < ApplicationController
   def create
+    if current_user
+      return render json: { code: current_user.inheritance_code,
+                            user: current_user.slice(:id, :name, :inheritance_code, :role) }
+    end
+
     user = nil
     User.transaction do
       user = User.create!(inheritance_code: SecureRandom.uuid, role: :guest)
       attach_ip_address!(user)
     end
 
+    establish_user_session(user)
     render json: { code: user.inheritance_code,
                    user: user.slice(:id, :name, :inheritance_code, :role) },
            status: :created
   end
 
   def verify
-    user = User.find_by(inheritance_code: params[:code])
+    user = if bool?(:restore) && current_user
+             current_user
+           else
+             User.find_by(inheritance_code: params[:code])
+           end
     return render json: { valid: false } unless user
     return head :forbidden if user.banned?
 
     attach_ip_address!(user)
+    establish_user_session(user)
 
     render json: { valid: true, user: user.slice(:id, :name, :inheritance_code, :role) }
   end
 
-  def session
+  def show_session
     return head :unauthorized unless current_user
 
     render json: current_user.slice(:id, :name, :role)
   end
 
+  def csrf
+    response.headers['Cache-Control'] = 'private, no-store'
+    render json: { token: form_authenticity_token }
+  end
+
+  def destroy_session
+    reset_session
+    response.headers['Cache-Control'] = 'private, no-store'
+    head :no_content
+  end
+
   def renew
     return head :unauthorized unless current_user
 
     user = current_user
     user.inheritance_code = SecureRandom.uuid
     user.save!
+    establish_user_session(user)
     render json: { code: user.inheritance_code }
   end
 
   def me
-    user = User.find_by(inheritance_code: params[:code])
-    return head :not_found unless user
+    user = current_user
+    return head :unauthorized unless user
 
+    attach_ip_address!(user)
     render json: user.slice(:id, :name, :inheritance_code, :role)
   end
 

backend/app/controllers/wiki_pages_controller.rb

@@ -55,9 +55,12 @@ class WikiPagesController < ApplicationController
 
   def show
     locale = resolve_locale!
-    tag_description = TagDescription.find_by(id: params[:id], language_code: locale.language_code)
+    reference = TagDescription.find_by(id: params[:id])
+    tag_description = reference && TagDescription.find_by(
+        tag_id: reference.tag_id, language_code: locale.language_code)
 
     return render_wiki_page_by_tag_description locale, tag_description if tag_description
+    return head :not_found if reference
 
     tag_group = TagGroup.find_by(id: params[:id])
     return render_tag_group locale, tag_group if tag_group
@@ -82,6 +85,17 @@ class WikiPagesController < ApplicationController
     head :not_found
   end
 
+  def tag_reference
+    locale = resolve_locale!
+    description = TagDescription.find_by(id: params[:id])
+    return head :not_found unless description
+
+    tag = Tag.preload(:tag_names, :materials, :deerjikists, :tag_descriptions,
+                      parents: [:tag_names, :materials, :deerjikists, :tag_descriptions])
+        .find(description.tag_id)
+    render json: TagRepr.base(tag, language_code: locale.language_code)
+  end
+
   def exists
     locale = resolve_locale!
     if TagDescription.exists?(id: params[:id], language_code: locale.language_code)