#399

backend/app/controllers/post_imports_controller.rb

@@ -0,0 +1,37 @@
+class PostImportsController < ApplicationController
+  before_action :require_member!
+
+  def preview
+    source =
+        if params[:format] == 'google_sheets'
+          PostImportGoogleSheetsFetcher.fetch!(params[:source], rate_key: current_user.id)
+        else
+          params[:source]
+        end
+    format = params[:format] == 'google_sheets' ? 'csv' : params[:format]
+    parsed = PostImportSourceParser.new(source:, format:,
+                                        has_header: params[:has_header], json_path: params[:json_path]).parse
+    url_column = params[:url_column].presence || (parsed[:columns].length == 1 ? 0 : nil)
+    return render_bad_request('URL 列を選択してください．') if url_column.nil?
+
+    rows = PostImportPreviewer.new(parsed:, url_column:, mappings: params[:mappings],
+                                   existing: params[:existing]).preview
+    render json: parsed.slice(:columns).merge(rows:)
+  rescue ArgumentError => e
+    render_bad_request(e.message)
+  end
+
+  def create
+    render json: PostImportRunner.new(actor: current_user, rows: params[:rows].to_a).run,
+           status: :created
+  end
+
+  private
+
+  def require_member!
+    return head :unauthorized unless current_user
+    return if current_user.gte_member?
+
+    head :forbidden
+  end
+end

backend/app/controllers/posts_controller.rb

@@ -142,37 +142,13 @@ class PostsController < ApplicationController
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.gte_member?
 
-    # TODO: サイトに応じて thumbnail_base 設定
+    post = PostCreator.new(actor: current_user,
-    title = params[:title].presence
+                           attributes: { title: params[:title], url: params[:url],
-    url = params[:url]
+                                         thumbnail: params[:thumbnail], tags: params[:tags],
-    thumbnail = params[:thumbnail]
+                                         original_created_from: params[:original_created_from],
-    tag_names = params[:tags].to_s.split
+                                         original_created_before: params[:original_created_before],
-    original_created_from = params[:original_created_from]
+                                         parent_post_ids: parse_parent_post_ids,
-    original_created_before = params[:original_created_before]
+                                         video_ms: params[:video_ms], duration: params[:duration] }).create!
-    parent_post_ids = parse_parent_post_ids
-    resized_thumbnail = thumbnail.present? ? Post.resized_thumbnail_attachment(thumbnail) : nil
-
-    post = Post.new(title:, url:, thumbnail_base: nil, uploaded_user: current_user,
-                    original_created_from:, original_created_before:)
-    post.thumbnail.attach(resized_thumbnail) if resized_thumbnail
-
-    ApplicationRecord.transaction do
-      post.save!
-
-      Tag.normalise_tags!(tag_names, deny_deprecated: true, with_sections: true) =>
-          { tags:, sections: }
-      TagVersioning.record_tag_snapshots!(tags, created_by_user: current_user)
-
-      tags = Tag.expand_parent_tags(tags).reject(&:deprecated?)
-      post.video_ms = normalise_video_ms(tags)
-      validate_video_sections!(post.video_ms, sections)
-      post.save!
-      sync_post_tags!(post, tags, sections)
-
-      sync_parent_posts!(post, parent_post_ids)
-
-      PostVersionRecorder.record!(post:, event_type: :create, created_by_user: current_user)
-    end
 
     post.reload
     render json: PostRepr.base(post), status: :created
@@ -182,7 +158,7 @@ class PostsController < ApplicationController
     render_unprocessable_entity '廃止済みタグは付与できません．', field: :tags
   rescue Tag::SectionLiteralParseError
     render_validation_error fields: { tags: ['タグ区間の記法が不正です．'] }
-  rescue VideoMsParseError
+  rescue PostCreator::VideoMsParseError
     render_validation_error fields: { video_ms: ['動画時間の記法が不正です．'] }
   rescue MiniMagick::Error
     render_validation_error fields: { thumbnail: ['サムネイル画像の変換に失敗しました．'] }

backend/app/services/post_creator.rb

@@ -0,0 +1,112 @@
+class PostCreator
+  class VideoMsParseError < ArgumentError; end
+
+  def initialize actor:, attributes:
+    @actor = actor
+    @attributes = attributes.symbolize_keys
+  end
+
+  def create!
+    post = Post.new(title: @attributes[:title].presence,
+                    url: @attributes[:url],
+                    thumbnail_base: @attributes[:thumbnail_base].presence,
+                    uploaded_user: @actor,
+                    original_created_from: @attributes[:original_created_from].presence,
+                    original_created_before: @attributes[:original_created_before].presence)
+    thumbnail = @attributes[:thumbnail]
+    post.thumbnail.attach(Post.resized_thumbnail_attachment(thumbnail)) if thumbnail.present?
+
+    ApplicationRecord.transaction do
+      post.save!
+      Tag.normalise_tags!(tag_names, deny_deprecated: true, with_sections: true) =>
+          { tags:, sections: }
+      TagVersioning.record_tag_snapshots!(tags, created_by_user: @actor)
+      tags = Tag.expand_parent_tags(tags).reject(&:deprecated?)
+      post.video_ms = normalise_video_ms(tags)
+      validate_video_sections!(post.video_ms, sections)
+      post.save!
+      sync_post_tags!(post, tags, sections)
+      sync_parent_posts!(post, parent_post_ids)
+      PostVersionRecorder.record!(post:, event_type: :create, created_by_user: @actor)
+    end
+    post
+  end
+
+  private
+
+  def tag_names = @attributes[:tags].to_s.split
+
+  def parent_post_ids
+    Array(@attributes[:parent_post_ids]).flat_map { _1.to_s.split }.map { |token|
+      id = Integer(token, exception: false)
+      raise ArgumentError, "親投稿 Id. が不正です: #{ token }" if id.nil? || id <= 0
+
+      id
+    }.uniq
+  end
+
+  def normalise_video_ms tags
+    return nil unless tags.any? { _1.id == Tag.video.id }
+
+    video_ms = @attributes[:video_ms]
+    if video_ms.present?
+      value = Integer(video_ms, exception: false)
+      raise VideoMsParseError unless value&.positive?
+
+      return value
+    end
+    duration = @attributes[:duration]
+    return nil if duration.blank?
+
+    return duration.to_i if duration.is_a?(Numeric) && duration.to_i.positive?
+
+    value = Tag.time_to_ms!(duration.to_s, tag_name: '動画時間')
+    raise VideoMsParseError unless value.positive?
+
+    value
+  rescue Tag::SectionLiteralParseError
+    raise VideoMsParseError
+  end
+
+  def validate_video_sections! video_ms, sections
+    return unless video_ms
+
+    sections.each_value do |ranges|
+      ranges.each do |begin_ms, end_ms|
+        next if begin_ms < video_ms && (!end_ms || end_ms <= video_ms)
+
+        post = Post.new
+        post.errors.add :video_ms, 'タグ区間が動画時間の範囲外です．'
+        raise ActiveRecord::RecordInvalid, post
+      end
+    end
+  end
+
+  def sync_post_tags! post, desired_tags, sections
+    desired_ids = desired_tags.map(&:id).to_set
+    current_ids = post.tags.pluck(:id).to_set
+    Tag.where(id: desired_ids - current_ids).find_each do |tag|
+      PostTag.create_or_find_by!(post:, tag:, created_user: @actor)
+    end
+    PostTagSection.where(post_id: post.id).destroy_all
+    sections.each do |tag_id, ranges|
+      ranges.each { |begin_ms, end_ms| PostTagSection.create!(post_id: post.id, tag_id:, begin_ms:, end_ms:) }
+    end
+    PostTag.where(post_id: post.id, tag_id: (current_ids - desired_ids).to_a).kept.find_each do |post_tag|
+      post_tag.discard_by!(@actor)
+    end
+  end
+
+  def sync_parent_posts! post, ids
+    if ids.include?(post.id)
+      post.errors.add :parent_post_ids, '自分自身を親投稿にはできません．'
+      raise ActiveRecord::RecordInvalid, post
+    end
+    missing = ids - Post.where(id: ids).pluck(:id)
+    if missing.present?
+      post.errors.add :parent_post_ids, "存在しない親投稿 Id. があります: #{ missing.join(' ') }"
+      raise ActiveRecord::RecordInvalid, post
+    end
+    ids.each { |parent_post_id| PostImplication.create_or_find_by!(post:, parent_post_id:) }
+  end
+end

backend/app/services/post_import_google_sheets_fetcher.rb

@@ -0,0 +1,59 @@
+class PostImportGoogleSheetsFetcher
+  HOST = 'docs.google.com'.freeze
+  PUBLICATION_ID = /\A[A-Za-z0-9_-]+\z/
+  GID = /\A\d+\z/
+  RATE_LIMIT = 10
+  RATE_WINDOW = 1.minute
+
+  def self.fetch! raw_url, rate_key:
+    new(raw_url, rate_key:).fetch!
+  end
+
+  def initialize raw_url, rate_key:
+    @raw_url = raw_url.to_s
+    @rate_key = rate_key.to_s
+  end
+
+  def fetch!
+    publication_id, gid = parse!
+    throttle!
+    csv_url = "https://#{ HOST }/spreadsheets/d/e/#{ publication_id }/pub?gid=#{ gid }&single=true&output=csv"
+    response = Preview::HttpFetcher.fetch(csv_url,
+                                          max_bytes: PostImportSourceParser::MAX_BYTES,
+                                          allowed_hosts: [HOST])
+    raise ArgumentError, 'スプレッドシートを CSV として取得できませんでした．' unless csv?(response)
+
+    response.body
+  rescue Preview::UrlSafety::UnsafeUrl, Preview::HttpFetcher::FetchFailed => e
+    raise ArgumentError, "スプレッドシートを取得できませんでした．ウェブ公開 URL を確認するか、ファイル保存又はコピー貼付けを使用してください: #{ e.message }"
+  end
+
+  private
+
+  def parse!
+    uri = URI.parse(@raw_url)
+    unless uri.scheme == 'https' && uri.host&.downcase == HOST && uri.query.blank?
+      raise ArgumentError, '公開 Google スプレッドシート URL を指定してください．'
+    end
+    match = uri.path.match(%r{\A/spreadsheets/d/e/([^/]+)/pubhtml\z})
+    gid = URI.decode_www_form(uri.fragment.to_s).to_h['gid']
+    unless match && PUBLICATION_ID.match?(match[1]) && GID.match?(gid.to_s)
+      raise ArgumentError, '公開 Google スプレッドシート URL の publication_id 又は gid が不正です．'
+    end
+
+    [match[1], gid]
+  rescue URI::InvalidURIError
+    raise ArgumentError, '公開 Google スプレッドシート URL が不正です．'
+  end
+
+  def throttle!
+    key = "post-import-google-sheets:#{ @rate_key }"
+    count = Rails.cache.increment(key, 1, expires_in: RATE_WINDOW, initial: 0)
+    raise ArgumentError, 'スプレッドシート取得の回数が多すぎます．しばらくしてから再試行してください．' if count > RATE_LIMIT
+  end
+
+  def csv? response
+    type = response.content_type.to_s.downcase
+    type.include?('text/csv') || response.body.valid_encoding?
+  end
+end

backend/app/services/post_import_previewer.rb

@@ -0,0 +1,79 @@
+class PostImportPreviewer
+  FIELDS = %w[title thumbnail_base original_created_from original_created_before duration tags parent_post_ids].freeze
+
+  def initialize parsed:, url_column:, mappings: { }, existing: 'skip'
+    @parsed = parsed
+    @url_column = url_column.to_i
+    @mappings = mappings.to_h.stringify_keys
+    @existing = existing == 'error' ? 'error' : 'skip'
+  end
+
+  def preview
+    urls = { }
+    @parsed[:rows].map do |row|
+      values = row[:values]
+      attributes = FIELDS.to_h { |field| [field, mapped_value(field, values)] }
+      url = values[@url_column].to_s.strip
+      metadata, warnings = fetch_metadata(url)
+      attributes = metadata.merge(attributes) { |_key, automatic, input| input.presence || automatic }
+      post = Post.new(url:)
+      post.valid?
+      normal_url = post.url
+      errors = post.errors.to_hash.transform_values(&:dup)
+      errors[:url] = ['URL が重複しています．'] if normal_url.present? && urls.key?(normal_url)
+      urls[normal_url] = true if normal_url.present?
+      if normal_url.present? && Post.exists?(url: normal_url)
+        @existing == 'error' ? errors[:url] = ['既存投稿です．'] : warnings << '既存投稿のためスキップします．'
+      end
+      validate_preview_tags(attributes['tags'], errors)
+      validate_parents(attributes['parent_post_ids'], errors)
+      { source_row: row[:source_row], url: normal_url || url, attributes:, warnings:, errors:,
+        status: errors.present? ? 'error' : (warnings.present? ? 'warning' : 'ready'),
+        existing: normal_url.present? && Post.exists?(url: normal_url) }
+    end
+  end
+
+  private
+
+  def mapped_value field, values
+    mapping = @mappings[field]
+    return '' if mapping.blank?
+    return mapping['value'].to_s if mapping['kind'] == 'fixed'
+
+    Array(mapping['columns']).filter_map { |index| values[index.to_i].to_s.presence }.join(field == 'tags' ? ' ' : '')
+  end
+
+  def fetch_metadata url
+    return [{ }, ['URL が空です．']] if url.blank?
+
+    data = PostMetadataFetcher.fetch(url)
+    warnings = []
+    warnings << 'タイトルを取得できませんでした．' if data[:title].blank?
+    warnings << 'サムネールを取得できませんでした．' if data[:thumbnail_base].blank?
+    [data.compact, warnings]
+  rescue Preview::UrlSafety::UnsafeUrl, Preview::HttpFetcher::FetchFailed, Preview::HttpFetcher::ResponseTooLarge => e
+    [{ }, ["メタデータを取得できませんでした: #{ e.message }"]]
+  end
+
+  def validate_preview_tags raw, errors
+    names = raw.to_s.split
+    return if names.empty?
+    if names.any? { _1.downcase.start_with?('nico:') }
+      errors[:tags] = ['ニコニコ・タグは直接指定できません．']
+      return
+    end
+    canonical = names.map { TagName.canonicalise(_1.sub(/\[.*\]\z/, '')).first }
+    if Tag.joins(:tag_name).where(tag_names: { name: canonical }, deprecated_at: nil).count < canonical.uniq.length
+      errors[:tags] = ['存在しないタグ又は廃止済みタグがあります．']
+    end
+  rescue Tag::SectionLiteralParseError
+    errors[:tags] = ['タグ区間の記法が不正です．']
+  end
+
+  def validate_parents raw, errors
+    ids = raw.to_s.split.map { Integer(_1, exception: false) }
+    return if ids.compact.empty? && raw.to_s.blank?
+    errors[:parent_post_ids] = ['親投稿 Id. が不正です．'] and return if ids.any? { _1.nil? || _1 <= 0 }
+    errors[:parent_post_ids] = ['存在しない親投稿 Id. があります．'] if Post.where(id: ids).count != ids.uniq.length
+  end
+end

backend/app/services/post_import_runner.rb

@@ -0,0 +1,24 @@
+class PostImportRunner
+  def initialize actor:, rows:
+    @actor = actor
+    @rows = rows
+  end
+
+  def run
+    results = @rows.map { |row| run_row(row.to_h.stringify_keys) }
+    { created: results.count { _1[:status] == 'created' }, skipped: results.count { _1[:status] == 'skipped' },
+      failed: results.count { _1[:status] == 'failed' }, rows: results }
+  end
+
+  private
+
+  def run_row row
+    return row.slice('source_row').merge(status: 'skipped') if row['status'] == 'skipped' || row['existing']
+    attributes = row.fetch('attributes', { }).to_h.transform_keys { _1.to_s.underscore }
+    attributes['url'] = row['url']
+    post = PostCreator.new(actor: @actor, attributes:).create!
+    { source_row: row['source_row'], status: 'created', post: PostRepr.base(post) }
+  rescue StandardError => e
+    { source_row: row['source_row'], status: 'failed', errors: { base: [e.message] } }
+  end
+end

backend/app/services/post_import_source_parser.rb

@@ -0,0 +1,56 @@
+require 'csv'
+
+class PostImportSourceParser
+  MAX_ROWS = 100
+  MAX_BYTES = 1.megabyte
+  MAX_CELL_BYTES = 20.kilobytes
+
+  def initialize source:, format:, has_header: false, json_path: nil
+    @source = source.to_s
+    @format = format.to_s
+    @has_header = ActiveModel::Type::Boolean.new.cast(has_header)
+    @json_path = json_path.to_s
+  end
+
+  def parse
+    raise ArgumentError, '入力が大きすぎます．' if @source.bytesize > MAX_BYTES
+
+    @format == 'json' ? parse_json : parse_delimited
+  end
+
+  private
+
+  def parse_delimited
+    separator = @format == 'csv' ? ',' : "\t"
+    table = CSV.parse(@source, col_sep: separator).map { |row| row.map { _1.to_s.strip } }
+    raise ArgumentError, '入力が空です．' if table.empty?
+
+    headers = @has_header ? table.shift : nil
+    ensure_limits!(table)
+    width = table.map(&:length).max.to_i
+    { columns: (0...width).map { |index| { key: index.to_s,
+                                          label: "#{ ('A'.ord + index).chr }：#{ headers&.[](index).presence || '列' }" } },
+      rows: table.each_with_index.map { |values, index| { source_row: index + (@has_header ? 2 : 1), values: } } }
+  rescue CSV::MalformedCSVError => e
+    raise ArgumentError, "CSV・TSV の形式が不正です: #{ e.message }"
+  end
+
+  def parse_json
+    value = JSON.parse(@source, max_nesting: 20)
+    @json_path.split('.').reject(&:blank?).each { |part| value = value.is_a?(Array) ? value[Integer(part)] : value.fetch(part) }
+    raise ArgumentError, 'JSON の投稿候補は配列にしてください．' unless value.is_a?(Array)
+
+    ensure_limits!(value)
+    keys = value.grep(Hash).flat_map(&:keys).map(&:to_s).uniq
+    { columns: keys.each_with_index.map { |key, index| { key:, label: "#{ ('A'.ord + index).chr }：#{ key }" } },
+      rows: value.each_with_index.map { |item, index| { source_row: index + 1,
+                                                         values: keys.map { item.is_a?(Hash) ? item[_1] || item[_1.to_sym] : nil } } } }
+  rescue JSON::ParserError, KeyError, ArgumentError => e
+    raise ArgumentError, "JSON の形式が不正です: #{ e.message }"
+  end
+
+  def ensure_limits! rows
+    raise ArgumentError, "取込件数は #{ MAX_ROWS } 件までです．" if rows.length > MAX_ROWS
+    raise ArgumentError, 'セルが大きすぎます．' if rows.flatten.any? { _1.to_s.bytesize > MAX_CELL_BYTES }
+  end
+end

backend/app/services/post_metadata_fetcher.rb

@@ -0,0 +1,14 @@
+class PostMetadataFetcher
+  def self.fetch raw_url
+    uri, = Preview::UrlSafety.validate(raw_url)
+    response = Preview::HttpFetcher.fetch(uri.to_s, max_bytes: Preview::ThumbnailFetcher::HTML_MAX_BYTES)
+    metadata = Preview::HtmlMetadataExtractor.extract(response)
+    document = Nokogiri::HTML.parse(response.body)
+    content = -> name { document.at_css("meta[property='#{ name }'], meta[name='#{ name }']")&.[]('content')&.strip.presence }
+    duration = content.call('og:video:duration') || content.call('video:duration')
+    { title: metadata[:title],
+      thumbnail_base: Preview::KnownSiteExtractor.thumbnail_url(uri) || metadata[:image_url],
+      original_created_from: content.call('article:published_time') || content.call('date'),
+      duration: duration&.to_f&.then { _1.positive? ? (_1 * 1_000).round : nil } }
+  end
+end

backend/app/services/preview/http_fetcher.rb

@@ -12,8 +12,12 @@ module Preview
 
     Response = Data.define(:body, :content_type, :url)
 
-    def self.fetch(raw_url, max_bytes: DEFAULT_MAX_BYTES, redirects: MAX_REDIRECTS)
+    def self.fetch(raw_url, max_bytes: DEFAULT_MAX_BYTES, redirects: MAX_REDIRECTS,
+                   allowed_hosts: nil)
       uri, addresses = UrlSafety.validate(raw_url)
+      if allowed_hosts && !allowed_hosts.include?(uri.host.downcase)
+        raise FetchFailed, '許可されてゐない redirect 先です．'
+      end
       response = request(uri, addresses.first, max_bytes)
 
       if response.is_a?(Net::HTTPRedirection)
@@ -50,7 +54,7 @@ module Preview
               raise FetchFailed, 'redirect 先が不正です．'
             end
 
-        return fetch(redirect_url, max_bytes:, redirects: redirects - 1)
+        return fetch(redirect_url, max_bytes:, redirects: redirects - 1, allowed_hosts:)
       end
 
       unless response.is_a?(Net::HTTPSuccess)

backend/config/routes.rb

@@ -33,6 +33,11 @@ Rails.application.routes.draw do
     get :thumbnail
   end
 
+  scope 'posts/import', controller: :post_imports do
+    post :preview
+    post '', action: :create
+  end
+
   resources :wiki_pages, path: 'wiki', only: [:index, :show, :create, :update] do
     collection do
       get :search

frontend/src/App.tsx

@@ -43,6 +43,7 @@ import PostDetailPage from '@/pages/posts/PostDetailPage'
 import PostHistoryPage from '@/pages/posts/PostHistoryPage'
 import PostListPage from '@/pages/posts/PostListPage'
 import PostNewPage from '@/pages/posts/PostNewPage'
+import PostImportPage from '@/pages/posts/PostImportPage'
 import PostSearchPage from '@/pages/posts/PostSearchPage'
 import ServiceUnavailable from '@/pages/ServiceUnavailable'
 import SettingPage from '@/pages/users/SettingPage'
@@ -75,6 +76,7 @@ const RouteTransitionWrapper = ({ animationMode, user, setUser }: {
 	    <Route path="/" element={<Navigate to="/posts" replace/>}/>
 	    <Route path="/posts" element={<PostListPage/>}/>
 	    <Route path="/posts/new" element={<PostNewPage user={user}/>}/>
+	    <Route path="/posts/import" element={<PostImportPage user={user}/>}/>
 	    <Route path="/posts/search" element={<PostSearchPage/>}/>
 	    <Route path="/posts/:id" element={<PostDetailRoute user={user}/>}/>
 	    <Route path="/posts/changes" element={<PostHistoryPage/>}/>
@@ -113,6 +115,7 @@ const RouteTransitionWrapper = ({ animationMode, user, setUser }: {
 	  <Route path="/" element={<Navigate to="/posts" replace/>}/>
 	  <Route path="/posts" element={<PostListPage/>}/>
 	  <Route path="/posts/new" element={<PostNewPage user={user}/>}/>
+	  <Route path="/posts/import" element={<PostImportPage user={user}/>}/>
 	  <Route path="/posts/search" element={<PostSearchPage/>}/>
 	  <Route path="/posts/:id" element={<PostDetailRoute user={user}/>}/>
 	  <Route path="/posts/changes" element={<PostHistoryPage/>}/>

frontend/src/components/TopNav.tsx

@@ -43,6 +43,7 @@ export const menuOutline = (
 	  { name: '一覧', to: '/posts' },
 	  { name: '検索', to: '/posts/search' },
 	  { name: '追加', to: '/posts/new' },
+	  { name: 'インポート', to: '/posts/import' },
 	  { name: '全体履歴', to: '/posts/changes' },
 	  { name: 'ヘルプ', to: '/wiki/ヘルプ:広場' }] },
       { name: 'タグ', to: '/tags', subMenu: [

frontend/src/pages/posts/PostImportPage.tsx

@@ -0,0 +1,184 @@
+import { useState } from 'react'
+import { Helmet } from 'react-helmet-async'
+
+import FieldError from '@/components/common/FieldError'
+import Form from '@/components/common/Form'
+import FormField from '@/components/common/FormField'
+import PageTitle from '@/components/common/PageTitle'
+import MainArea from '@/components/layout/MainArea'
+import { Button } from '@/components/ui/button'
+import { toast } from '@/components/ui/use-toast'
+import { SITE_TITLE } from '@/config'
+import { apiPost } from '@/lib/api'
+import { canEditContent } from '@/lib/users'
+import { inputClass } from '@/lib/utils'
+import Forbidden from '@/pages/Forbidden'
+
+import type { FC } from 'react'
+
+import type { User } from '@/types'
+
+type Props = { user: User | null }
+type Column = { key: string, label: string }
+type ImportRow = {
+    sourceRow: number
+    url: string
+    attributes: Record<string, string>
+    warnings: string[]
+    errors: Record<string, string[]>
+    status: 'ready' | 'warning' | 'error'
+    existing: boolean }
+
+
+const detectFormat = (source: string): 'csv' | 'tsv' =>
+    source.includes ('\t') ? 'tsv' : (source.includes (',') ? 'csv' : 'tsv')
+
+const publicGoogleSheetURL = (source: string): boolean =>
+    /^https:\/\/docs\.google\.com\/spreadsheets\/d\/e\/[A-Za-z0-9_-]+\/pubhtml#gid=\d+$/.test (
+        source.trim ())
+
+
+const PostImportPage: FC<Props> = ({ user }) => {
+  const [source, setSource] = useState ('')
+  const [format, setFormat] = useState<'csv' | 'tsv' | 'json' | 'google_sheets'> ('tsv')
+  const [hasHeader, setHasHeader] = useState (false)
+  const [jsonPath, setJsonPath] = useState ('')
+  const [urlColumn, setUrlColumn] = useState ('0')
+  const [columns, setColumns] = useState<Column[]> ([])
+  const [rows, setRows] = useState<ImportRow[]> ([])
+  const [mappings, setMappings] = useState<Record<string, { columns: string[] }>> ({ })
+  const [existing, setExisting] = useState<'skip' | 'error'> ('skip')
+  const [loading, setLoading] = useState (false)
+  const editable = canEditContent (user)
+
+  const preview = async () => {
+    setLoading (true)
+    try
+    {
+      const data = await apiPost<{ columns: Column[], rows: ImportRow[] }> ('/posts/import/preview', {
+        source,
+        format,
+        has_header: hasHeader,
+        json_path: jsonPath,
+        url_column: urlColumn,
+        mappings,
+        existing })
+      setColumns (data.columns)
+      setRows (data.rows)
+    }
+    catch
+    {
+      toast ({ title: '読込みに失敗しました', description: '入力形式を確認してください。' })
+    }
+    finally
+    {
+      setLoading (false)
+    }
+  }
+
+  const updateAttribute = (index: number, field: string, value: string) => {
+    setRows (current => current.map ((row, rowIndex) =>
+        rowIndex === index ? { ...row, attributes: { ...row.attributes, [field]: value } } : row))
+  }
+
+  const submit = async () => {
+    const targets = rows.filter (row => row.status !== 'error' && !(row.existing && existing === 'skip'))
+    if (targets.length === 0)
+      return
+    setLoading (true)
+    try
+    {
+      const result = await apiPost<{ created: number, skipped: number, failed: number }> ('/posts/import',
+                                                                                              { rows: targets })
+      toast ({ title: `登録完了: ${result.created} 件`,
+              description: `スキップ ${result.skipped} 件、失敗 ${result.failed} 件` })
+    }
+    catch
+    {
+      toast ({ title: '登録に失敗しました' })
+    }
+    finally
+    {
+      setLoading (false)
+    }
+  }
+
+  if (!(editable))
+    return <Forbidden/>
+
+  return (
+      <MainArea>
+	<Helmet><title>{`投稿インポート | ${SITE_TITLE}`}</title></Helmet>
+	<PageTitle>投稿インポート</PageTitle>
+	{rows.length === 0 ? (
+	    <Form>
+	      <p className="text-sm text-neutral-600 dark:text-neutral-300">
+		URL を一行に一件ずつ貼り付けるか、CSV・TSV・JSON を入力してください。
+	      </p>
+	      {publicGoogleSheetURL (source) && (
+		<fieldset className="space-y-1 rounded border p-3 dark:border-neutral-700">
+		  <legend>公開 Google スプレッドシート URL</legend>
+		  <label className="mr-3"><input type="radio" checked={format === 'google_sheets'}
+				 onChange={() => setFormat ('google_sheets')}/>シート内データを読み込む</label>
+		  <label><input type="radio" checked={format !== 'google_sheets'}
+				 onChange={() => setFormat ('tsv')}/>URL 自体を投稿として扱う</label>
+		</fieldset>)}
+	      <FormField label="入力形式">
+		{() => <select value={format} onChange={ev => setFormat (ev.target.value as typeof format)}
+				 className={inputClass (false)}>
+		  <option value="tsv">テキスト・TSV</option><option value="csv">CSV</option>
+		  <option value="json">JSON</option>
+		  <option value="google_sheets">公開 Google スプレッドシート</option>
+		</select>}
+	      </FormField>
+	      <FormField label="入力データ">
+		{() => <textarea value={source} rows={12} className={inputClass (false)}
+			 onChange={ev => { setSource (ev.target.value); if (format !== 'json' && format !== 'google_sheets') setFormat (detectFormat (ev.target.value)) }}/>} 
+	      </FormField>
+	      <input type="file" accept=".txt,.csv,.tsv,.json" onChange={ev => {
+		const file = ev.target.files?.[0]
+		if (file) file.text ().then (text => { setSource (text); setFormat (file.name.endsWith ('.json') ? 'json' : detectFormat (text)) })
+	      }}/>
+	      {format !== 'json' && <label className="flex gap-2"><input type="checkbox" checked={hasHeader}
+				 onChange={ev => setHasHeader (ev.target.checked)}/>見出し行を使用する</label>}
+	      {format === 'json' && <FormField label="投稿候補の位置（例: data.posts）">
+		{() => <input value={jsonPath} onChange={ev => setJsonPath (ev.target.value)} className={inputClass (false)}/>} 
+	      </FormField>}
+	      {format === 'google_sheets' && <p className="text-sm text-neutral-600 dark:text-neutral-300">
+		非公開シートには対応していません。ウェブ公開 URL を使用するか、CSV を保存して選択、又は内容を貼り付けてください。
+	      </p>}
+	      <Button type="button" onClick={preview} disabled={loading || !(source)}>読込み・確認</Button>
+	    </Form>) : (
+	    <div className="space-y-4">
+	      <div className="flex flex-wrap gap-3 rounded border p-3 dark:border-neutral-700">
+		<label>URL 列 <select value={urlColumn} onChange={ev => setUrlColumn (ev.target.value)}>
+		  {columns.map ((column, index) => <option key={column.key} value={index}>{column.label}</option>)}
+		</select></label>
+		<label>既存投稿 <select value={existing} onChange={ev => setExisting (ev.target.value as typeof existing)}>
+		  <option value="skip">スキップ</option><option value="error">エラー</option>
+		</select></label>
+		{['title', 'thumbnail_base', 'original_created_from', 'original_created_before', 'duration', 'tags', 'parent_post_ids'].map (field =>
+		    <label key={field}>{field}<select value={mappings[field]?.columns?.[0] ?? ''}
+			 onChange={ev => setMappings (current => ({ ...current, [field]: { columns: ev.target.value === '' ? [] : [ev.target.value] } }))}>
+		      <option value="">指定なし</option>{columns.map ((column, index) => <option key={column.key} value={index}>{column.label}</option>)}
+		    </select></label>)}
+		<Button type="button" variant="outline" onClick={preview} disabled={loading}>再読込み</Button>
+	      </div>
+	      <div className="space-y-3 md:hidden">{rows.map ((row, index) => <RowCard key={row.sourceRow} row={row} index={index} update={updateAttribute}/>)}</div>
+	      <div className="hidden overflow-x-auto md:block"><table className="w-full text-sm"><thead><tr><th>行</th><th>URL</th><th>タイトル</th><th>サムネール</th><th>日時</th><th>動画時間</th><th>タグ</th><th>親投稿</th><th>状態</th></tr></thead>
+		<tbody>{rows.map ((row, index) => <tr key={row.sourceRow} className="border-t dark:border-neutral-700"><td>{row.sourceRow}</td><td><input value={row.url} onChange={ev => { const next = [...rows]; next[index] = { ...row, url: ev.target.value }; setRows (next) }}/></td><td><input value={row.attributes.title ?? ''} onChange={ev => updateAttribute (index, 'title', ev.target.value)}/></td><td>{row.attributes.thumbnailBase && <img src={row.attributes.thumbnailBase} alt="サムネール" className="h-12"/>}</td><td>{row.attributes.originalCreatedFrom ?? ''}</td><td>{row.attributes.duration ?? ''}</td><td><input value={row.attributes.tags ?? ''} onChange={ev => updateAttribute (index, 'tags', ev.target.value)}/></td><td><input value={row.attributes.parentPostIds ?? ''} onChange={ev => updateAttribute (index, 'parent_post_ids', ev.target.value)}/></td><td>{row.status}<FieldError messages={[...row.warnings, ...Object.values (row.errors).flat ()]}/></td></tr>)}</tbody></table></div>
+	      <Button type="button" onClick={submit} disabled={loading}>有効な投稿を一括登録</Button>
+	    </div>)}
+	</MainArea>)
+}
+
+
+const RowCard = ({ row, index, update }: { row: ImportRow, index: number, update: (index: number, field: string, value: string) => void }) => (
+    <article className="space-y-2 rounded border bg-white p-3 text-neutral-900 dark:border-neutral-700 dark:bg-neutral-900 dark:text-neutral-100">
+	<p>行 {row.sourceRow}・{row.status}</p><input value={row.url} readOnly className={inputClass (false)}/>
+	<label>タイトル<input value={row.attributes.title ?? ''} onChange={ev => update (index, 'title', ev.target.value)} className={inputClass (false)}/></label>
+	<label>タグ<input value={row.attributes.tags ?? ''} onChange={ev => update (index, 'tags', ev.target.value)} className={inputClass (false)}/></label>
+	<FieldError messages={[...row.warnings, ...Object.values (row.errors).flat ()]}/>
+    </article>)
+
+export default PostImportPage

frontend/src/pages/posts/PostNewPage.tsx

@@ -49,6 +49,7 @@ const PostNewPage: FC<Props> = ({ user }) => {
   const [url, setURL] = useState ('')
 
   const thumbnailPreviewRef = useRef ('')
+  const urlRef = useRef ('')
   const videoFlg =
       useMemo (() => tags.split (/\s+/).some (tag => tag.replace (/\[.*\]$/, '') === '動画'),
                [tags])
@@ -84,11 +85,13 @@ const PostNewPage: FC<Props> = ({ user }) => {
   }
 
   const fetchTitle = useCallback (async () => {
-    setTitleLoading (true)
+	const requestedURL = url
+	setTitleLoading (true)
     try
     {
       const data = await apiGet<{ title: string }> ('/preview/title', { params: { url } })
-      setTitle (data.title || '')
+	  if (requestedURL === urlRef.current)
+	    setTitle (current => current || data.title || '')
     }
     finally
     {
@@ -97,6 +100,7 @@ const PostNewPage: FC<Props> = ({ user }) => {
   }, [url])
 
   const fetchThumbnail = useCallback (async () => {
+	const requestedURL = url
     setThumbnailPreview ('')
     setThumbnailFile (null)
     setThumbnailLoading (true)
@@ -107,10 +111,13 @@ const PostNewPage: FC<Props> = ({ user }) => {
       const data = await apiGet<Blob> ('/preview/thumbnail',
 				       { params: { url }, responseType: 'blob' })
       const imageURL = URL.createObjectURL (data)
-      setThumbnailPreview (imageURL)
+	  if (requestedURL === urlRef.current)
-      setThumbnailFile (new File ([data],
+	    {
-				  'thumbnail.png',
+	      setThumbnailPreview (current => current || imageURL)
-				  { type: data.type || 'image/png' }))
+	      setThumbnailFile (current => current || new File ([data],
+								  'thumbnail.png',
+								  { type: data.type || 'image/png' }))
+	    }
     }
     finally
     {
@@ -122,6 +129,20 @@ const PostNewPage: FC<Props> = ({ user }) => {
     thumbnailPreviewRef.current = thumbnailPreview
   }, [thumbnailPreview])
 
+  useEffect (() => {
+	urlRef.current = url
+  }, [url])
+
+  useEffect (() => {
+	if (!(url))
+	  return
+	const timer = window.setTimeout (() => {
+	  fetchTitle ().catch (() => undefined)
+	  fetchThumbnail ().catch (() => undefined)
+	}, 500)
+    return () => window.clearTimeout (timer)
+  }, [fetchThumbnail, fetchTitle, url])
+
   if (!(editable))
     return <Forbidden/>
 
@@ -159,7 +180,7 @@ const PostNewPage: FC<Props> = ({ user }) => {
 			 onChange={ev => setTitle (ev.target.value)}
 			 disabled={titleLoading}/>
 		  <div className="flex flex-wrap items-center gap-2 text-sm">
-		    <span>必要なタイミングで URL から取得できます．</span>
+		    <span>URL 入力後に自動取得します．</span>
 		    <Button
 			type="button"
 			variant="outline"
@@ -176,7 +197,7 @@ const PostNewPage: FC<Props> = ({ user }) => {
 	    {({ describedBy, invalid }) => (
 		<>
 		  <div className="mb-2 flex flex-wrap items-center gap-2 text-sm">
-		    <span>必要なタイミングで URL から取得できます．</span>
+		    <span>URL 入力後に自動取得します．</span>
 		    <Button
 			type="button"
 			variant="outline"