#399

backend/app/controllers/post_imports_controller.rb

@@ -2,7 +2,7 @@ class PostImportsController < ApplicationController
   before_action :require_member!
 
   def preview
-    rows = PostImportPreviewer.new(existing: params[:existing]).preview_rows(
+    rows = PostImportPreviewer.new.preview_rows(
         rows: PostImportUrlListParser.parse(params[:source]))
     render json: { rows: }
   rescue ArgumentError => e
@@ -13,18 +13,17 @@ class PostImportsController < ApplicationController
     rows = normalised_import_rows(allow_warning_fields: true)
     changed_row = Integer(params[:changed_row], exception: false)
     result =
-        PostImportPreviewer.new(existing: params[:existing])
+        PostImportPreviewer.new.preview_rows(rows:,
-          .preview_rows(rows:, fetch_metadata: changed_row, metadata_cache: {})
+                                             fetch_metadata: changed_row,
+                                             metadata_cache: { })
     render json: { rows: result }
   rescue ArgumentError => e
     render_bad_request(e.message)
   end
 
   def create
-    result = PostImportRunner.new(
+    result = PostImportRunner.new(actor: current_user,
-        actor: current_user,
+                                  rows: normalised_import_rows).run
-        rows: normalised_import_rows,
-        existing: params[:existing]).run
     render json: result, status: result[:created].positive? ? :created : :ok
   rescue ArgumentError => e
     render_bad_request(e.message)

backend/app/services/post_import_previewer.rb

@@ -8,9 +8,11 @@ class PostImportPreviewer
     'tags',
     'parent_post_ids',
   ].freeze
-  def initialize existing: 'skip'
+  FETCH_WARNING_FIELDS = ['url', 'title', 'thumbnail_base'].freeze
-    @existing = existing == 'error' ? 'error' : 'skip'
+  EXISTING_SKIP_WARNING = '既存投稿のためスキップします．'.freeze
-  end
+  TITLE_FETCH_WARNING = 'タイトルを取得できませんでした．'.freeze
+  THUMBNAIL_FETCH_WARNING = 'サムネールを取得できませんでした．'.freeze
+  METADATA_FETCH_WARNING = 'メタデータを取得できませんでした．'.freeze
 
   def preview_rows rows:, fetch_metadata: true, metadata_cache: { }
     urls = {}
@@ -30,48 +32,60 @@ class PostImportPreviewer
     attributes = initial_attributes(row)
     provenance = initial_provenance(row)
     tag_sources = initial_tag_sources(row, attributes, provenance)
+    field_warnings = initial_field_warnings(row)
+    base_warnings = initial_base_warnings(row)
     url = row[:url].to_s.strip
     provenance['url'] = 'manual'
     normal_url = normalised_url(url)
     url_for_metadata = normal_url || url
     existing_post = normal_url.present? && Post.exists?(url: normal_url)
 
-    validation_warnings = []
     validation_errors = {}
     validation_errors[:url] = ['URL が不正です．'] if normal_url.blank?
     validation_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? && existing_post
-      if @existing == 'error'
-        validation_errors[:url] = ['既存投稿です．']
-      else
-        validation_warnings << '既存投稿のためスキップします．'
-      end
-    end
 
     if row[:metadata_url].present? && row[:metadata_url] != url_for_metadata
       clear_automatic_values!(attributes, provenance, tag_sources)
+      clear_fetch_warnings!(field_warnings)
+    end
+
+    if normal_url.present? && existing_post
+      add_field_warning!(field_warnings, 'url', EXISTING_SKIP_WARNING)
+      attributes['tags'] = merged_tags(tag_sources, provenance['tags'])
+      warnings_present = field_warnings.values.any?(&:present?) || base_warnings.present?
+      return {
+        source_row: row[:source_row],
+        url: normal_url,
+        attributes:,
+        provenance:,
+        tag_sources:,
+        metadata_url: url_for_metadata,
+        field_warnings:,
+        base_warnings:,
+        validation_errors:,
+        status: validation_errors.present? ? 'error' : (warnings_present ? 'warning' : 'ready'),
+      }
     end
 
-    fetch_warnings = Array(row[:fetch_warnings]).dup
     should_fetch = should_fetch_metadata?(fetch_metadata, row[:source_row].to_i)
-    if should_fetch && !(existing_post && @existing == 'skip')
+    if should_fetch
-      metadata, fetch_warnings =
+      clear_fetch_warnings!(field_warnings)
-        metadata_for(url_for_metadata, metadata_cache, fetch_warnings)
+      metadata = metadata_for(url_for_metadata, metadata_cache)
-      apply_metadata!(attributes, provenance, tag_sources, metadata)
+      apply_metadata!(attributes, provenance, tag_sources, metadata[:data])
+      apply_fetch_warnings!(field_warnings, metadata[:warnings])
     end
 
     attributes['url'] = url
     validate_basic_data(attributes, validation_errors)
-    validate_preview_tags(
+    validate_preview_tags(merged_tags(tag_sources, provenance['tags']),
-      merged_tags(tag_sources, provenance['tags']),
+                          validation_errors,
-      validation_errors,
+                          field_warnings)
-      validation_warnings,
-    )
     validate_parents(attributes['parent_post_ids'], validation_errors)
     attributes.delete('url')
     attributes['tags'] = merged_tags(tag_sources, provenance['tags'])
 
+    warnings_present = field_warnings.values.any?(&:present?) || base_warnings.present?
     {
       source_row: row[:source_row],
       url: normal_url || url,
@@ -79,14 +93,10 @@ class PostImportPreviewer
       provenance:,
       tag_sources:,
       metadata_url: url_for_metadata,
-      fetch_warnings:,
+      field_warnings:,
-      validation_warnings:,
+      base_warnings:,
-      warnings: fetch_warnings + validation_warnings,
       validation_errors:,
-      status: validation_errors.present? \
+      status: validation_errors.present? ? 'error' : (warnings_present ? 'warning' : 'ready'),
-                ? 'error' \
-                : ((fetch_warnings + validation_warnings).present? ? 'warning' : 'ready'),
-      existing: existing_post,
     }
   end
 
@@ -100,12 +110,12 @@ class PostImportPreviewer
   end
 
   def initial_attributes row
-    attributes = row[:attributes]&.stringify_keys || {}
+    attributes = row[:attributes]&.stringify_keys || { }
     FIELDS.to_h { |field| [field, attributes[field].to_s] }
   end
 
   def initial_provenance row
-    provenance = row[:provenance]&.stringify_keys || {}
+    provenance = row[:provenance]&.stringify_keys || { }
     FIELDS.to_h { |field| [field, provenance[field].presence || 'automatic'] }
       .merge('url' => 'manual')
   end
@@ -118,6 +128,14 @@ class PostImportPreviewer
     sources
   end
 
+  def initial_field_warnings row
+    (row[:field_warnings] || { }).stringify_keys.transform_values { |value| Array(value).map(&:to_s) }
+  end
+
+  def initial_base_warnings row
+    Array(row[:base_warnings]).map(&:to_s)
+  end
+
   def clear_automatic_values! attributes, provenance, tag_sources
     ['title', 'thumbnail_base', 'original_created_from',
      'original_created_before', 'duration'].each do |field|
@@ -127,18 +145,24 @@ class PostImportPreviewer
     attributes['tags'] = merged_tags(tag_sources, provenance['tags'])
   end
 
-  def metadata_for url, cache, previous_warnings
+  def clear_fetch_warnings! field_warnings
+    FETCH_WARNING_FIELDS.each do |field|
+      field_warnings.delete(field)
+    end
+  end
+
+  def metadata_for url, cache
     cache[url] ||= fetch_metadata(url)
   end
 
   def fetch_metadata url
-    return [{}, ['URL が空です．']] if url.blank?
+    return { data: { }, warnings: { 'url' => ['URL が空です．'] } } if url.blank?
 
-    data = PostMetadataFetcher.fetch(url).stringify_keys
+    data = PostMetadataFetcher.fetch(url).stringify_keys.compact
-    warnings = []
+    warnings = { }
-    warnings << 'タイトルを取得できませんでした．' if data['title'].blank?
+    add_field_warning!(warnings, 'title', TITLE_FETCH_WARNING) 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?
+    add_field_warning!(warnings, 'thumbnail_base', THUMBNAIL_FETCH_WARNING) if data['thumbnail_base'].blank?
-    [data.compact, warnings]
+    { data:, warnings: }
   rescue Preview::UrlSafety::UnsafeUrl,
          Preview::HttpFetcher::FetchFailed,
          Preview::HttpFetcher::ResponseTooLarge => e
@@ -146,7 +170,7 @@ class PostImportPreviewer
       "post_import_metadata_fetch_failure "\
       "#{ { error: e.class.name, message: e.message }.to_json }",
     )
-    [{}, ['メタデータを取得できませんでした．']]
+    { data: { }, warnings: { 'url' => [METADATA_FETCH_WARNING] } }
   end
 
   def apply_metadata! attributes, provenance, tag_sources, metadata
@@ -165,13 +189,26 @@ class PostImportPreviewer
     end
   end
 
+  def apply_fetch_warnings! field_warnings, warnings
+    warnings.each do |field, values|
+      values.each do |value|
+        add_field_warning!(field_warnings, field, value)
+      end
+    end
+  end
+
+  def add_field_warning! field_warnings, field, message
+    field_warnings[field] ||= []
+    field_warnings[field] << message unless field_warnings[field].include?(message)
+  end
+
   def merged_tags sources, origin = nil
     return sources['manual'].to_s if origin == 'manual'
 
     sources['automatic'].to_s
   end
 
-  def validate_preview_tags raw, errors, warnings
+  def validate_preview_tags raw, errors, field_warnings
     names = raw.to_s.split
     return if names.empty?
     if names.any? { _1.downcase.start_with?('nico:') }
@@ -185,7 +222,9 @@ class PostImportPreviewer
     errors[:tags] = ["廃止済みタグがあります: #{ deprecated.join(' ') }"] if deprecated.present?
     known = existing.reject(&:deprecated?).map(&:name)
     new_tags = parsed.uniq - known
-    warnings << "新規タグを作成します: #{ new_tags.join(' ') }" if new_tags.present?
+    if new_tags.present?
+      add_field_warning!(field_warnings, 'tags', "新規タグを作成します: #{ new_tags.join(' ') }")
+    end
   rescue Tag::SectionLiteralParseError
     errors[:tags] = ['タグ区間の記法が不正です．']
   end

backend/app/services/post_import_row_normaliser.rb

@@ -64,10 +64,10 @@ class PostImportRowNormaliser
     return keys unless allow_warning_fields
 
     keys + [
-      { fetch_warnings: [] },
+      { field_warnings: {} },
-      { fetchWarnings: [] },
+      { fieldWarnings: {} },
-      { validation_warnings: [] },
+      { base_warnings: [] },
-      { validationWarnings: [] },
+      { baseWarnings: [] },
     ]
   end
   private_class_method :permitted_keys
@@ -141,10 +141,12 @@ class PostImportRowNormaliser
   def self.normalise_warning_values! normalised, allow_warning_fields:
     return unless allow_warning_fields
 
-    %w[fetch_warnings validation_warnings].each do |field|
+    field_warnings = normalised['field_warnings']
-      values = normalised[field]
+    unless field_warnings.nil? || field_warnings.is_a?(Hash)
-      next if values.nil?
+      raise ArgumentError, '警告の形式が不正です．'
-
+    end
+    field_warnings&.each do |key, values|
+      raise ArgumentError, '警告の形式が不正です．' unless ATTRIBUTE_FIELDS.include?(key) || key == 'url'
       unless values.is_a?(Array) && values.all? { _1.is_a?(String) }
         raise ArgumentError, '警告の形式が不正です．'
       end
@@ -152,6 +154,14 @@ class PostImportRowNormaliser
         raise ArgumentError, '警告が大きすぎます．'
       end
     end
+
+    base_warnings = normalised['base_warnings']
+    return if base_warnings.nil?
+
+    unless base_warnings.is_a?(Array) && base_warnings.all? { _1.is_a?(String) }
+      raise ArgumentError, '警告の形式が不正です．'
+    end
+    raise ArgumentError, '警告が大きすぎます．' if base_warnings.any? { _1.bytesize > PostImportUrlListParser::MAX_URL_BYTES }
   end
   private_class_method :normalise_warning_values!
 

backend/app/services/post_import_runner.rb

@@ -1,8 +1,7 @@
 class PostImportRunner
-  def initialize actor:, rows:, existing: 'skip'
+  def initialize actor:, rows:
     @actor = actor
     @rows = rows
-    @existing = existing == 'error' ? 'error' : 'skip'
   end
 
   def run
@@ -21,8 +20,7 @@ class PostImportRunner
 
   def run_row row
     attributes = row.fetch('attributes', { }).transform_keys { _1.to_s.underscore }
-    preview = PostImportPreviewer.new(existing: @existing)
+    preview = PostImportPreviewer.new.preview_rows(
-      .preview_rows(
         rows: [{
           source_row: row['source_row'],
           url: row['url'],
@@ -31,7 +29,7 @@ class PostImportRunner
           tag_sources: row['tag_sources'],
         }],
         fetch_metadata: false).first
-    if @existing == 'skip' && preview[:existing]
+    if Array(preview.dig(:field_warnings, 'url')).include?(PostImportPreviewer::EXISTING_SKIP_WARNING)
       return row.slice('source_row').merge(status: 'skipped')
     end
 

backend/app/services/post_import_url_list_parser.rb

@@ -11,7 +11,7 @@ class PostImportUrlListParser
       url = line.strip
       next if url.blank?
 
-      raise ArgumentError, 'URL が長すぎます．' if url.bytesize > MAX_URL_BYTES
+      raise ArgumentError, "#{ index + 1 } 行目: URL が長すぎます．" if url.bytesize > MAX_URL_BYTES
 
       { source_row: index + 1, url: }
     }

frontend/src/components/posts/import/PostImportRowDialog.tsx

@@ -49,6 +49,10 @@ const buildDraft = (row: PostImportRow): Draft => ({
     tags: String (row.attributes.tags ?? ''),
     parentPostIds: String (row.attributes.parentPostIds ?? '') })
 
+const warningClass =
+    'mt-1 rounded-md border border-amber-300 bg-amber-50 px-3 py-2 text-sm '
+    + 'text-amber-700 dark:border-amber-900 dark:bg-amber-950 dark:text-amber-200'
+
 
 const PostImportRowDialog: FC<Props> = (
     { open, row, saving, onOpenChange, onSave },
@@ -102,46 +106,81 @@ const PostImportRowDialog: FC<Props> = (
 		    label="URL"
 		    value={draft.url}
 		    origin={originOf (row, 'url')}
+		    warnings={row.fieldWarnings.url}
+		    errors={[
+			...(row.validationErrors.url ?? []),
+			...(row.importErrors?.url ?? [])]}
 		    onChange={value => update ('url', value)}/>
 		<DialogField
 		    label="タイトル"
 		    value={draft.title}
 		    origin={originOf (row, 'title')}
+		    warnings={row.fieldWarnings.title}
+		    errors={[
+			...(row.validationErrors.title ?? []),
+			...(row.importErrors?.title ?? [])]}
 		    onChange={value => update ('title', value)}/>
 		<DialogField
 		    label="サムネール基底 URL"
 		    value={draft.thumbnailBase}
 		    origin={originOf (row, 'thumbnailBase')}
+		    warnings={row.fieldWarnings.thumbnailBase}
+		    errors={[
+			...(row.validationErrors.thumbnailBase ?? []),
+			...(row.importErrors?.thumbnailBase ?? [])]}
 		    onChange={value => update ('thumbnailBase', value)}/>
 		<div className="grid gap-4 md:grid-cols-2">
 		  <DialogField
 		      label="作成日時 From"
 		      value={draft.originalCreatedFrom}
 		      origin={originOf (row, 'originalCreatedFrom')}
+		      errors={[
+			  ...(row.validationErrors.originalCreatedFrom ?? []),
+			  ...(row.importErrors?.originalCreatedFrom ?? [])]}
 		      onChange={value => update ('originalCreatedFrom', value)}/>
 		  <DialogField
 		      label="作成日時 Before"
 		      value={draft.originalCreatedBefore}
 		      origin={originOf (row, 'originalCreatedBefore')}
+		      errors={[
+			  ...(row.validationErrors.originalCreatedBefore ?? []),
+			  ...(row.importErrors?.originalCreatedBefore ?? [])]}
 		      onChange={value => update ('originalCreatedBefore', value)}/>
 		</div>
 		<DialogField
 		    label="動画時間"
 		    value={draft.duration}
 		    origin={originOf (row, 'duration')}
+		    errors={[
+			...(row.validationErrors.duration ?? []),
+			...(row.validationErrors.videoMs ?? []),
+			...(row.importErrors?.duration ?? []),
+			...(row.importErrors?.videoMs ?? [])]}
 		    onChange={value => update ('duration', value)}/>
 		<DialogArea
 		    label="タグ"
 		    value={draft.tags}
 		    origin={originOf (row, 'tags')}
+		    warnings={row.fieldWarnings.tags}
+		    errors={[
+			...(row.validationErrors.tags ?? []),
+			...(row.importErrors?.tags ?? [])]}
 		    onChange={value => update ('tags', value)}/>
 		<DialogField
 		    label="親投稿"
 		    value={draft.parentPostIds}
 		    origin={originOf (row, 'parentPostIds')}
+		    errors={[
+			...(row.validationErrors.parentPostIds ?? []),
+			...(row.importErrors?.parentPostIds ?? [])]}
 		    onChange={value => update ('parentPostIds', value)}/>
-		<FieldError messages={Object.values (row.validationErrors ?? { }).flat ()}/>
+		{row.baseWarnings.length > 0 && (
-		<FieldError messages={Object.values (row.importErrors ?? { }).flat ()}/>
+		    <div className={warningClass}>
+		      {row.baseWarnings.map ((message, index) => (
+			  <div key={`${ message }-${ index }`}>{message}</div>))}
+		    </div>)}
+		<FieldError messages={row.validationErrors.base}/>
+		<FieldError messages={row.importErrors?.base}/>
 	      </div>
 	    </div>
 
@@ -164,10 +203,12 @@ const PostImportRowDialog: FC<Props> = (
 }
 
 const DialogField = (
-    { label, value, origin, onChange }: {
+    { label, value, origin, warnings, errors, onChange }: {
 	label:    string
 	value:    string
 	origin:   PostImportOrigin
+	warnings?: string[]
+	errors?:   string[]
 	onChange: (value: string) => void },
 ) => (
     <label className="block space-y-1">
@@ -179,13 +220,21 @@ const DialogField = (
 	  value={value}
 	  onChange={ev => onChange (ev.target.value)}
 	  className={inputClass (false)}/>
+      {warnings && warnings.length > 0 && (
+	  <div className={warningClass}>
+	    {warnings.map ((message, index) => (
+		<div key={`${ message }-${ index }`}>{message}</div>))}
+	  </div>)}
+      <FieldError messages={errors}/>
     </label>)
 
 const DialogArea = (
-    { label, value, origin, onChange }: {
+    { label, value, origin, warnings, errors, onChange }: {
 	label:    string
 	value:    string
 	origin:   PostImportOrigin
+	warnings?: string[]
+	errors?:   string[]
 	onChange: (value: string) => void },
 ) => (
     <label className="block space-y-1">
@@ -198,6 +247,12 @@ const DialogArea = (
 	  rows={4}
 	  onChange={ev => onChange (ev.target.value)}
 	  className={inputClass (false)}/>
+      {warnings && warnings.length > 0 && (
+	  <div className={warningClass}>
+	    {warnings.map ((message, index) => (
+		<div key={`${ message }-${ index }`}>{message}</div>))}
+	  </div>)}
+      <FieldError messages={errors}/>
     </label>)
 
 export default PostImportRowDialog

frontend/src/components/posts/import/PostImportRowSummary.tsx

@@ -1,6 +1,7 @@
 import { Button } from '@/components/ui/button'
 import { cn } from '@/lib/utils'
 
+import PrefetchLink from '@/components/PrefetchLink'
 import PostImportStatusBadge from '@/components/posts/import/PostImportStatusBadge'
 import ThumbnailPreview from '@/components/posts/import/ThumbnailPreview'
 
@@ -48,6 +49,11 @@ const summaryError = (row: PostImportRow): string | null => {
     return Object.values (row.importErrors ?? { }).flat ()[0] ?? null
 }
 
+const summaryWarning = (row: PostImportRow): string | null =>
+    Object.values (row.fieldWarnings ?? { }).flat ()[0]
+    ?? row.baseWarnings?.[0]
+    ?? null
+
 const summaryDate = (row: PostImportRow): string =>
     [row.attributes.originalCreatedFrom, row.attributes.originalCreatedBefore]
 	.filter (_1 => typeof _1 === 'string' && _1 !== '')
@@ -56,6 +62,7 @@ const summaryDate = (row: PostImportRow): string =>
 
 const PostImportRowSummary: FC<Props> = ({ row, onEdit }) => {
     const error = summaryError (row)
+    const warning = error == null ? summaryWarning (row) : null
     const importStatus = row.importStatus ?? 'pending'
 
     return (
@@ -89,6 +96,21 @@ const PostImportRowSummary: FC<Props> = ({ row, onEdit }) => {
 		{summaryDate (row) || '日時未取得'}
 		{row.attributes.duration ? ` / ${ row.attributes.duration }` : ''}
 	      </div>
+	      {row.createdPostId && (
+		  <PrefetchLink
+		      to={`/posts/${ row.createdPostId }`}
+		      className="inline-block text-xs text-sky-700 underline
+				 dark:text-sky-300">
+		    投稿 #{row.createdPostId}
+		  </PrefetchLink>)}
+	      {warning && (
+		  <div className="text-xs text-amber-700 dark:text-amber-200">
+		    {warning}
+		  </div>)}
+	      {error && (
+		  <div className="text-xs text-red-700 dark:text-red-200">
+		    {error}
+		  </div>)}
 	    </div>
 	    <div className="space-y-1">
 	      <PostImportStatusBadge value={importStatus}/>
@@ -96,7 +118,7 @@ const PostImportRowSummary: FC<Props> = ({ row, onEdit }) => {
 	    <div className="space-y-1">
 	      {error
 	       ? <PostImportStatusBadge value="error"/>
-	       : <PostImportStatusBadge value="ready"/>}
+	       : (warning ? <PostImportStatusBadge value="warning"/> : <PostImportStatusBadge value="ready"/>)}
 	    </div>
 	    <div className="flex justify-end">
 	      <Button
@@ -128,11 +150,23 @@ const PostImportRowSummary: FC<Props> = ({ row, onEdit }) => {
 		<div className="flex flex-wrap gap-2">
 		  <PostImportStatusBadge value={row.status}/>
 		  <PostImportStatusBadge value={importStatus}/>
+		  {warning && <PostImportStatusBadge value="warning"/>}
 		</div>
+		{row.createdPostId && (
+		    <PrefetchLink
+			to={`/posts/${ row.createdPostId }`}
+			className="inline-block text-xs text-sky-700 underline
+				   dark:text-sky-300">
+		      投稿 #{row.createdPostId}
+		    </PrefetchLink>)}
 		{error && (
 		    <div className="text-xs text-red-700 dark:text-red-200">
 		      {error}
 		    </div>)}
+		{warning && (
+		    <div className="text-xs text-amber-700 dark:text-amber-200">
+		      {warning}
+		    </div>)}
 	      </div>
 	    </div>
 	    <Button

frontend/src/components/posts/import/ThumbnailPreview.tsx

@@ -31,9 +31,10 @@ const ThumbnailPreview: FC<Props> = ({ url, alt = 'サムネール', className =
 	return (
 	    <div
 		className={`${ className } flex items-center justify-center rounded border
-			    border-red-300 bg-red-50 p-2 text-center text-xs text-red-700
+			    border-amber-300 bg-amber-50 p-2 text-center text-xs
-			    dark:border-red-900 dark:bg-red-950 dark:text-red-200`}>
+			    text-amber-700 dark:border-amber-900 dark:bg-amber-950
-	      表示不可
+			    dark:text-amber-200`}>
+	      サムネールを表示できません
 	    </div>)
       }
 

frontend/src/lib/postImportSession.ts

@@ -12,13 +12,13 @@ export type PostImportRow = {
     sourceRow:         number
     url:               string
     attributes:        Record<string, PostImportAttributeValue>
-    warnings:          string[]
+    fieldWarnings:     Record<string, string[]>
+    baseWarnings:      string[]
     validationErrors:  Record<string, string[]>
     importErrors?:     Record<string, string[]>
     provenance:        Record<string, PostImportOrigin>
     tagSources?:       Record<PostImportOrigin, string>
     status:            'ready' | 'warning' | 'error'
-    existing:          boolean
     metadataUrl?:      string
     createdPostId?:    number
     importStatus?:     PostImportStatus }
@@ -33,13 +33,223 @@ export type PostImportSession = {
     version:    number
     savedAt:    string
     source:     string
-    existing:   'skip' | 'error'
     rows:       PostImportRow[]
     repairMode: PostImportRepairMode }
 
-const SESSION_VERSION = 1
+export type PostImportSourceIssue = {
+    sourceRow: number
+    message:   string
+    url:       string }
+
+type StorageErrorHandler = (message: string) => void
+
+const SESSION_VERSION = 2
 const SESSION_PREFIX = 'post-import-session:'
 const SOURCE_DRAFT_KEY = 'post-import-source-draft'
+const SESSION_MAX_AGE_MS = 24 * 60 * 60 * 1000
+const MAX_ROWS = 100
+const MAX_URL_BYTES = 20 * 1024
+
+
+const isPlainObject = (value: unknown): value is Record<string, unknown> =>
+    typeof value === 'object' && value != null && !(Array.isArray (value))
+
+
+const sessionKey = (sessionId: string): string => `${ SESSION_PREFIX }${ sessionId }`
+
+
+const readStorage = (
+    key:       string,
+    onError?:  StorageErrorHandler,
+): string | null => {
+    if (typeof window === 'undefined')
+      return null
+
+    try
+    {
+	return sessionStorage.getItem (key)
+    }
+    catch
+    {
+	onError?.('保存済みデータを読み込めませんでした．')
+	return null
+    }
+}
+
+
+const writeStorage = (
+    key:       string,
+    value:     string,
+    onError?:  StorageErrorHandler,
+): boolean => {
+    if (typeof window === 'undefined')
+      return false
+
+    try
+    {
+	sessionStorage.setItem (key, value)
+	return true
+    }
+    catch
+    {
+	onError?.('ブラウザへ保存できませんでした．')
+	return false
+    }
+}
+
+
+const removeStorage = (
+    key:       string,
+    onError?:  StorageErrorHandler,
+) => {
+    if (typeof window === 'undefined')
+      return
+
+    try
+    {
+	sessionStorage.removeItem (key)
+    }
+    catch
+    {
+	onError?.('保存済みデータを削除できませんでした．')
+    }
+}
+
+
+const truncateUrl = (value: string): string =>
+    value.length > 120 ? `${ value.slice (0, 117) }…` : value
+
+
+const bytesize = (value: string): number =>
+    new TextEncoder ().encode (value).length
+
+
+const normaliseImportUrl = (value: string): string | null => {
+    const trimmed = value.trim ()
+    if (!(trimmed))
+      return null
+
+    try
+    {
+	const url = new URL (trimmed)
+	if (!(url.protocol === 'http:' || url.protocol === 'https:'))
+	  return null
+	if (!(url.host))
+	  return null
+
+	url.hostname = url.hostname.toLowerCase ()
+	if (url.pathname.endsWith ('/'))
+	  url.pathname = url.pathname.replace (/\/+$/, '')
+	return url.toString ()
+    }
+    catch
+    {
+	return null
+    }
+}
+
+
+const ensureStringListRecord = (value: unknown): Record<string, string[]> | null => {
+    if (!(isPlainObject (value)))
+      return null
+
+    const result: Record<string, string[]> = { }
+    for (const [key, entry] of Object.entries (value))
+      {
+	if (!(Array.isArray (entry)) || !(entry.every (_1 => typeof _1 === 'string')))
+	  return null
+	result[key] = entry
+      }
+    return result
+}
+
+
+const isValidStatus = (
+    value: unknown,
+): value is PostImportRow['status'] =>
+    value === 'ready' || value === 'warning' || value === 'error'
+
+
+const isValidImportStatus = (
+    value: unknown,
+): value is PostImportStatus =>
+    value === 'pending'
+    || value === 'created'
+    || value === 'skipped'
+    || value === 'failed'
+
+
+const isValidOrigin = (
+    value: unknown,
+): value is PostImportOrigin =>
+    value === 'automatic' || value === 'manual'
+
+
+const sanitiseRow = (value: unknown): PostImportRow | null => {
+    if (!(isPlainObject (value)))
+      return null
+    if (!(Number.isInteger (value.sourceRow)) || Number (value.sourceRow) <= 0)
+      return null
+    if (typeof value.url !== 'string')
+      return null
+    if (!(isPlainObject (value.attributes)))
+      return null
+    if (!(isPlainObject (value.provenance)))
+      return null
+    if (!(isValidStatus (value.status)))
+      return null
+    if (value.importStatus != null && !(isValidImportStatus (value.importStatus)))
+      return null
+
+    const validationErrors = ensureStringListRecord (value.validationErrors)
+    const fieldWarnings = ensureStringListRecord (value.fieldWarnings)
+    if (validationErrors == null || fieldWarnings == null)
+      return null
+
+    const importErrors =
+	value.importErrors == null
+	? undefined
+	: ensureStringListRecord (value.importErrors)
+    if (value.importErrors != null && importErrors == null)
+      return null
+    if (!(Array.isArray (value.baseWarnings))
+	|| !(value.baseWarnings.every (_1 => typeof _1 === 'string')))
+      return null
+
+    const provenanceEntries = Object.entries (value.provenance)
+    if (!(provenanceEntries.every (([, origin]) => isValidOrigin (origin))))
+      return null
+
+    if (value.tagSources != null)
+      {
+	if (!(isPlainObject (value.tagSources)))
+	  return null
+	if (!(Object.values (value.tagSources).every (_1 => typeof _1 === 'string')))
+	  return null
+      }
+
+    return {
+	sourceRow: Number (value.sourceRow),
+	url: value.url,
+	attributes: value.attributes as Record<string, PostImportAttributeValue>,
+	fieldWarnings,
+	baseWarnings: value.baseWarnings,
+	validationErrors,
+	importErrors,
+	provenance: value.provenance as Record<string, PostImportOrigin>,
+	tagSources: value.tagSources as Record<PostImportOrigin, string> | undefined,
+	status: value.status,
+	metadataUrl: typeof value.metadataUrl === 'string' ? value.metadataUrl : undefined,
+	createdPostId:
+	    Number.isInteger (value.createdPostId) ? Number (value.createdPostId) : undefined,
+	importStatus: value.importStatus }
+}
+
+
+const isExpiredSession = (savedAt: string): boolean => {
+    const value = Date.parse (savedAt)
+    return Number.isNaN (value) || Date.now () - value > SESSION_MAX_AGE_MS
+}
 
 
 export const createPostImportSessionId = (): string =>
@@ -48,82 +258,122 @@ export const createPostImportSessionId = (): string =>
     : `${ Date.now () }-${ Math.random ().toString (36).slice (2) }`
 
 
-export const loadPostImportSourceDraft = (): {
+export const cleanupExpiredPostImportSessions = (
-    source:   string
+    onError?: StorageErrorHandler,
-    existing: 'skip' | 'error' } => {
+) => {
     if (typeof window === 'undefined')
-      return { source: '', existing: 'skip' }
+      return
 
     try
     {
-	const raw = sessionStorage.getItem (SOURCE_DRAFT_KEY)
+	for (let i = 0; i < sessionStorage.length; ++i)
-	if (raw == null)
+	  {
-	  return { source: '', existing: 'skip' }
+	    const key = sessionStorage.key (i)
+	    if (key == null || !(key.startsWith (SESSION_PREFIX)))
+	      continue
 
-	const value = JSON.parse (raw) as {
+	    const raw = sessionStorage.getItem (key)
-	    source?: string
+	    if (raw == null)
-	    existing?: 'skip' | 'error' }
+	      continue
-	return {
+	    try
-	    source: typeof value.source === 'string' ? value.source : '',
+	    {
-	    existing: value.existing === 'error' ? 'error' : 'skip' }
+		const value = JSON.parse (raw) as { savedAt?: string }
+		if (typeof value.savedAt !== 'string' || isExpiredSession (value.savedAt))
+		  {
+		    sessionStorage.removeItem (key)
+		    --i
+		  }
+	    }
+	    catch
+	    {
+		sessionStorage.removeItem (key)
+		--i
+	    }
+	  }
     }
     catch
     {
-	return { source: '', existing: 'skip' }
+	onError?.('保存済みデータを整理できませんでした．')
+    }
+}
+
+
+export const loadPostImportSourceDraft = (
+    onError?: StorageErrorHandler,
+): { source: string } => {
+    const raw = readStorage (SOURCE_DRAFT_KEY, onError)
+    if (raw == null)
+      return { source: '' }
+
+    try
+    {
+	const value = JSON.parse (raw) as { source?: string }
+	return { source: typeof value.source === 'string' ? value.source : '' }
+    }
+    catch
+    {
+	return { source: '' }
     }
 }
 
 
 export const savePostImportSourceDraft = (
-    source:   string,
+    source:    string,
-    existing: 'skip' | 'error',
+    onError?:  StorageErrorHandler,
+): boolean =>
+    writeStorage (SOURCE_DRAFT_KEY, JSON.stringify ({ source }), onError)
+
+
+export const clearPostImportSourceDraft = (
+    onError?: StorageErrorHandler,
 ) => {
-    if (typeof window === 'undefined')
+    removeStorage (SOURCE_DRAFT_KEY, onError)
-      return
-
-    sessionStorage.setItem (SOURCE_DRAFT_KEY, JSON.stringify ({ source, existing }))
 }
 
 
-const sessionKey = (sessionId: string): string => `${ SESSION_PREFIX }${ sessionId }`
-
-
 export const savePostImportSession = (
     sessionId: string,
     session:   Omit<PostImportSession, 'version' | 'savedAt'>,
-) => {
+    onError?:  StorageErrorHandler,
-    if (typeof window === 'undefined')
+): boolean =>
-      return
+    writeStorage (
-
+	sessionKey (sessionId),
-    sessionStorage.setItem (sessionKey (sessionId), JSON.stringify ({
+	JSON.stringify ({
-	...session,
+	    ...session,
-	version: SESSION_VERSION,
+	    version: SESSION_VERSION,
-	savedAt: new Date ().toISOString () }))
+	    savedAt: new Date ().toISOString () }),
-}
+	onError,
+    )
 
 
 export const loadPostImportSession = (
     sessionId: string,
+    onError?: StorageErrorHandler,
 ): PostImportSession | null => {
-    if (typeof window === 'undefined')
+    const raw = readStorage (sessionKey (sessionId), onError)
+    if (raw == null)
       return null
 
     try
     {
-	const raw = sessionStorage.getItem (sessionKey (sessionId))
-	if (raw == null)
-	  return null
-
 	const value = JSON.parse (raw) as Partial<PostImportSession>
 	if (value.version !== SESSION_VERSION || !(Array.isArray (value.rows)))
 	  return null
+	if (typeof value.savedAt !== 'string' || isExpiredSession (value.savedAt))
+	  {
+	    removeStorage (sessionKey (sessionId), onError)
+	    return null
+	  }
+
+	const rows = value.rows.map (sanitiseRow)
+	if (rows.some (_1 => _1 == null))
+	  return null
 
 	return {
 	    version: SESSION_VERSION,
-	    savedAt: typeof value.savedAt === 'string' ? value.savedAt : '',
+	    savedAt: value.savedAt,
 	    source: typeof value.source === 'string' ? value.source : '',
-	    existing: value.existing === 'error' ? 'error' : 'skip',
+	    rows: rows as PostImportRow[],
-	    rows: value.rows as PostImportRow[],
 	    repairMode: value.repairMode === 'failed' ? 'failed' : 'all' }
     }
     catch
@@ -133,44 +383,122 @@ export const loadPostImportSession = (
 }
 
 
+const rowChanged = (
+    previous: PostImportRow,
+    next:     PostImportRow,
+): boolean =>
+    previous.url !== next.url
+    || JSON.stringify (previous.attributes) !== JSON.stringify (next.attributes)
+    || JSON.stringify (previous.provenance) !== JSON.stringify (next.provenance)
+    || JSON.stringify (previous.tagSources ?? { }) !== JSON.stringify (next.tagSources ?? { })
+
+
 export const mergeValidatedImportRows = (
     current:   PostImportRow[],
     validated: PostImportRow[],
-): PostImportRow[] =>
+): PostImportRow[] => {
-    current
+    const validatedMap = new Map (validated.map (row => [row.sourceRow, row]))
-	.map (previous => {
+    return current.map (previous => {
-	    if (previous.importStatus === 'created')
+	if (previous.importStatus === 'created')
-	      return previous
+	  return previous
 
-	    const row = validated.find (_1 => _1.sourceRow === previous.sourceRow)
+	const row = validatedMap.get (previous.sourceRow)
-	    return row
+	if (row == null)
-		? {
+	  return previous
-		    ...row,
+
-		    importStatus: previous.importStatus,
+	const fieldWarnings =
-		    createdPostId: previous.createdPostId,
+	    Object.keys (row.fieldWarnings).length > 0 || row.metadataUrl !== previous.metadataUrl
-		    importErrors: previous.importErrors,
+	    ? { ...row.fieldWarnings }
-		    validationErrors: row.validationErrors ?? { } }
+	    : { ...previous.fieldWarnings }
-		: previous
+	for (const [field, origin] of Object.entries (row.provenance))
-	})
+	  {
-	.concat (validated.filter (row =>
+	    if (origin === 'manual' && String (row.attributes[field] ?? '') !== '')
-	    !(current.some (_1 => _1.sourceRow === row.sourceRow))))
+	      delete fieldWarnings[field]
+	  }
+
+	return {
+	    ...previous,
+	    url: row.url,
+	    attributes: row.attributes,
+	    provenance: row.provenance,
+	    tagSources: row.tagSources,
+	    fieldWarnings,
+	    baseWarnings:
+		row.baseWarnings.length > 0 || row.metadataUrl !== previous.metadataUrl
+		? row.baseWarnings
+		: previous.baseWarnings,
+	    validationErrors: row.validationErrors,
+	    status: row.status,
+	    metadataUrl: row.metadataUrl }
+    })
+}
+
+
+export const mergePreviewImportRows = (
+    current: PostImportRow[],
+    preview: PostImportRow[],
+): PostImportRow[] => {
+    const currentMap = new Map (current.map (row => [row.sourceRow, row]))
+    return preview.map (row => {
+	const previous = currentMap.get (row.sourceRow)
+	if (previous == null)
+	  return row
+	if (previous.importStatus === 'created')
+	  return previous
+
+	const mergedAttributes = { ...row.attributes }
+	const mergedProvenance = { ...row.provenance }
+	for (const [field, origin] of Object.entries (previous.provenance))
+	  {
+	    if (origin !== 'manual' || field === 'url')
+	      continue
+	    if (field in previous.attributes)
+	      mergedAttributes[field] = previous.attributes[field]
+	    mergedProvenance[field] = 'manual'
+	  }
+
+	const mergedTagSources =
+	    previous.provenance.tags === 'manual'
+	    ? {
+		automatic: row.tagSources?.automatic ?? '',
+		manual: previous.tagSources?.manual ?? String (previous.attributes.tags ?? '') }
+	    : row.tagSources
+
+	const nextRow = {
+	    ...row,
+	    attributes: mergedAttributes,
+	    provenance: mergedProvenance,
+	    tagSources: mergedTagSources,
+	    createdPostId: previous.createdPostId,
+	    importStatus: previous.importStatus,
+	    importErrors: previous.importErrors }
+
+	if (rowChanged (previous, nextRow))
+	  {
+	    nextRow.importStatus = 'pending'
+	    nextRow.importErrors = undefined
+	  }
+	return nextRow
+    })
+}
 
 
 export const mergeImportResults = (
     rows:    PostImportRow[],
     results: PostImportResultRow[],
-): PostImportRow[] =>
+): PostImportRow[] => {
-    rows.map (row => {
+    const resultMap = new Map (results.map (row => [row.sourceRow, row]))
-	const result = results.find (_1 => _1.sourceRow === row.sourceRow)
+    return rows.map (row => {
+	const result = resultMap.get (row.sourceRow)
 	return result
 	    ? {
 		...row,
 		importStatus: result.status,
 		createdPostId: result.post?.id,
-		importErrors: result.errors,
+		importErrors: result.errors }
-		validationErrors: row.validationErrors }
 	    : row
     })
+}
 
 
 export const retryImportRow = (
@@ -183,12 +511,6 @@ export const retryImportRow = (
 	: row)
 
 
-export const rowMessages = (row: PostImportRow): string[] => [
-    ...row.warnings,
-    ...Object.values (row.validationErrors ?? { }).flat (),
-    ...Object.values (row.importErrors ?? { }).flat ()]
-
-
 export const countImportSourceLines = (source: string): number =>
     source
 	.split (/\r\n|\n|\r/)
@@ -197,25 +519,96 @@ export const countImportSourceLines = (source: string): number =>
 	.length
 
 
-export const countImportSourceValidLines = (source: string): number =>
+export const validateImportSource = (
-    source
+    source: string,
-	.split (/\r\n|\n|\r/)
+): PostImportSourceIssue[] => {
-	.map (_1 => _1.trim ())
+    const lines = source.split (/\r\n|\n|\r/)
-	.filter (_1 => /^https?:\/\//.test (_1))
+    const issues: PostImportSourceIssue[] = []
-	.length
+    const seen = new Map<string, number> ()
+    let count = 0
+
+    lines.forEach ((rawLine, index) => {
+	const value = rawLine.trim ()
+	if (!(value))
+	  return
+
+	++count
+	const sourceRow = index + 1
+	const displayUrl = truncateUrl (value)
+	const normalised = normaliseImportUrl (value)
+	if (count > MAX_ROWS)
+	  {
+	    issues.push ({
+		sourceRow,
+		message: `取込件数は ${ MAX_ROWS } 件までです．`,
+		url: displayUrl })
+	    return
+	  }
+	if (!(value.startsWith ('http://') || value.startsWith ('https://')))
+	  {
+	    issues.push ({
+		sourceRow,
+		message: 'HTTP または HTTPS の URL ではありません．',
+		url: displayUrl })
+	    return
+	  }
+	if (bytesize (value) > MAX_URL_BYTES)
+	  {
+	    issues.push ({
+		sourceRow,
+		message: 'URL が長すぎます．',
+		url: displayUrl })
+	    return
+	  }
+	if (normalised == null)
+	  {
+	    issues.push ({
+		sourceRow,
+		message: 'URL の形式が不正です．',
+		url: displayUrl })
+	    return
+	  }
+	const duplicateRow = seen.get (normalised)
+	if (duplicateRow != null)
+	  {
+	    issues.push ({
+		sourceRow,
+		message: `${ duplicateRow } 行目と同じ URL です．`,
+		url: displayUrl })
+	    return
+	  }
+	seen.set (normalised, sourceRow)
+    })
+
+    return issues
+}
+
+
+const hasSkipWarning = (row: PostImportRow): boolean =>
+    (row.fieldWarnings.url ?? []).includes ('既存投稿のためスキップします．')
 
 
 export const submittableImportRows = (rows: PostImportRow[]): PostImportRow[] =>
-    rows.filter (row => row.importStatus == null || row.importStatus === 'pending')
+    rows.filter (row => {
+	if (row.importStatus === 'created')
+	  return false
+	if (row.importStatus === 'skipped')
+	  return false
+	if (hasSkipWarning (row))
+	  return false
+	if (row.importStatus === 'failed')
+	  return false
+	return row.importStatus == null || row.importStatus === 'pending'
+    })
 
 
 export const reviewSummaryCounts = (rows: PostImportRow[]) => ({
     total: rows.length,
     submittable: rows.filter (row =>
-	(row.importStatus == null || row.importStatus === 'pending')
+	submittableImportRows ([row]).length > 0
 	&& Object.keys (row.validationErrors ?? { }).length === 0).length,
     invalid: rows.filter (row => Object.keys (row.validationErrors ?? { }).length > 0).length,
     skipPlanned: rows.filter (row =>
-	row.existing && row.importStatus !== 'created' && row.status !== 'error').length,
+	hasSkipWarning (row) && row.importStatus !== 'created').length,
     created: rows.filter (row => row.importStatus === 'created').length,
     failed: rows.filter (row => row.importStatus === 'failed').length })

frontend/src/pages/posts/PostImportResultPage.tsx

@@ -13,7 +13,8 @@ import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { apiPost } from '@/lib/api'
 import { canEditContent } from '@/lib/users'
-import { loadPostImportSession,
+import { clearPostImportSourceDraft,
+	 loadPostImportSession,
 	 mergeImportResults,
 	 retryImportRow,
 	 savePostImportSession,
@@ -63,7 +64,8 @@ const PostImportResultPage: FC<Props> = ({ user }) => {
 	if (!(sessionId))
 	  return
 
-	const loaded = loadPostImportSession (sessionId)
+	const loaded = loadPostImportSession (sessionId, message =>
+	    toast ({ title: '取込状態を復元できませんでした', description: message }))
 	setSession (loaded)
 	setMissing (loaded == null)
     }, [sessionId])
@@ -72,7 +74,8 @@ const PostImportResultPage: FC<Props> = ({ user }) => {
 	if (!(sessionId) || !(session))
 	  return
 
-	savePostImportSession (sessionId, session)
+	savePostImportSession (sessionId, session, message =>
+	    toast ({ title: '取込状態を保存できませんでした', description: message }))
     }, [session, sessionId])
 
     const counts = useMemo (() => ({
@@ -104,8 +107,7 @@ const PostImportResultPage: FC<Props> = ({ user }) => {
 			attributes: target.attributes,
 			provenance: target.provenance,
 			tagSources: target.tagSources,
-			metadataUrl: target.metadataUrl }],
+			metadataUrl: target.metadataUrl }] })
-		    existing: session.existing })
 	    setSession (current =>
 		current
 		? { ...current, rows: mergeImportResults (current.rows, result.rows) }
@@ -126,7 +128,12 @@ const PostImportResultPage: FC<Props> = ({ user }) => {
 	const nextSession = { ...session, repairMode: 'failed' as const }
 	setSession (nextSession)
 	if (sessionId)
-	  savePostImportSession (sessionId, nextSession)
+	  {
+	    const saved = savePostImportSession (sessionId, nextSession, message =>
+		toast ({ title: '取込状態を保存できませんでした', description: message }))
+	    if (!(saved))
+	      return
+	  }
 	navigate (`/posts/import/${ sessionId }/review?edit=${ sourceRow }`)
     }
 
@@ -185,6 +192,13 @@ const PostImportResultPage: FC<Props> = ({ user }) => {
 			<div className="text-xs text-neutral-500 dark:text-neutral-400">
 			  {row.url}
 			</div>
+			{row.createdPostId && (
+			    <PrefetchLink
+				to={`/posts/${ row.createdPostId }`}
+				className="inline-block text-xs text-sky-700 underline
+					   dark:text-sky-300">
+			      投稿 #{row.createdPostId}
+			    </PrefetchLink>)}
 			<FieldError messages={Object.values (row.importErrors ?? { }).flat ()}/>
 		      </div>
 
@@ -222,7 +236,10 @@ const PostImportResultPage: FC<Props> = ({ user }) => {
 		  onClick={() => {
 		      const nextSession = { ...session, repairMode: 'all' as const }
 		      setSession (nextSession)
-		      savePostImportSession (sessionId, nextSession)
+		      const saved = savePostImportSession (sessionId, nextSession, message =>
+			  toast ({ title: '取込状態を保存できませんでした', description: message }))
+		      if (!(saved))
+			return
 		      navigate (`/posts/import/${ sessionId }/review`)
 		  }}>
 		確認画面へ戻る
@@ -230,7 +247,11 @@ const PostImportResultPage: FC<Props> = ({ user }) => {
 	      <Button
 		  type="button"
 		  variant="outline"
-		  onClick={() => navigate ('/posts/import')}>
+		  onClick={() => {
+		      clearPostImportSourceDraft (message =>
+			  toast ({ title: '入力内容を削除できませんでした', description: message }))
+		      navigate ('/posts/import')
+		  }}>
 		新しい URL リストを入力
 	      </Button>
 	    </div>

frontend/src/pages/posts/PostImportReviewPage.tsx

@@ -19,7 +19,6 @@ import { loadPostImportSession,
 	 mergeImportResults,
 	 mergeValidatedImportRows,
 	 reviewSummaryCounts,
-	 rowMessages,
 	 savePostImportSession,
 	 submittableImportRows,
 	 type PostImportResultRow,
@@ -59,7 +58,8 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	if (!(sessionId))
 	  return
 
-	const loaded = loadPostImportSession (sessionId)
+	const loaded = loadPostImportSession (sessionId, message =>
+	    toast ({ title: '取込状態を復元できませんでした', description: message }))
 	setSession (loaded)
 	setMissing (loaded == null)
     }, [sessionId])
@@ -68,7 +68,8 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	if (!(sessionId) || !(session))
 	  return
 
-	savePostImportSession (sessionId, session)
+	savePostImportSession (sessionId, session, message =>
+	    toast ({ title: '取込状態を保存できませんでした', description: message }))
     }, [session, sessionId])
 
     const rows = session?.rows ?? []
@@ -160,8 +161,15 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	try
 	{
 	    const validated = await apiPost<{ rows: PostImportRow[] }> ('/posts/import/validate', {
-		rows: nextRows.filter (row => row.importStatus !== 'created'),
+		rows: nextRows
-		existing: session.existing,
+		    .filter (row => row.importStatus !== 'created')
+		    .map (row => ({
+			sourceRow: row.sourceRow,
+			url: row.url,
+			attributes: row.attributes,
+			provenance: row.provenance,
+			tagSources: row.tagSources,
+			metadataUrl: row.metadataUrl })),
 		changed_row: urlChanged ? editingRow.sourceRow : -1 })
 	    updateSessionRows (mergeValidatedImportRows (nextRows, validated.rows))
 	    setSearchParams ({ })
@@ -178,33 +186,6 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	}
     }
 
-    const updateExisting = async (value: 'skip' | 'error') => {
-	if (!(session))
-	  return
-
-	const pendingRows = session.rows.map (row =>
-	    row.importStatus === 'created'
-	    ? row
-	    : {
-		...row,
-		importStatus: 'pending' as const,
-		importErrors: undefined })
-	setSession ({ ...session, existing: value, rows: pendingRows })
-	setLoading (true)
-	try
-	{
-	    const validated = await apiPost<{ rows: PostImportRow[] }> ('/posts/import/validate', {
-		rows: pendingRows.filter (row => row.importStatus !== 'created'),
-		existing: value,
-		changed_row: -1 })
-	    updateSessionRows (mergeValidatedImportRows (pendingRows, validated.rows))
-	}
-	finally
-	{
-	    setLoading (false)
-	}
-    }
-
     const submit = async () => {
 	if (!(sessionId) || !(session) || submittable.length === 0)
 	  return
@@ -223,12 +204,14 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 			attributes: row.attributes,
 			provenance: row.provenance,
 			tagSources: row.tagSources,
-			metadataUrl: row.metadataUrl })),
+			metadataUrl: row.metadataUrl })) })
-		    existing: session.existing })
 	    const nextRows = mergeImportResults (session.rows, result.rows)
 	    const nextSession = { ...session, rows: nextRows, repairMode: 'all' as const }
 	    setSession (nextSession)
-	    savePostImportSession (sessionId, nextSession)
+	    const saved = savePostImportSession (sessionId, nextSession, message =>
+		toast ({ title: '取込状態を保存できませんでした', description: message }))
+	    if (!(saved))
+	      return
 	    navigate (`/posts/import/${ sessionId }/result`)
 	}
 	catch
@@ -264,7 +247,7 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	    <title>{`投稿インポート確認 | ${ SITE_TITLE }`}</title>
 	  </Helmet>
 
-	  <div className="mx-auto max-w-6xl space-y-4 p-4 pb-28">
+	  <div className="mx-auto flex max-w-6xl flex-col gap-4 p-4 pb-8">
 	    <PageTitle>投稿情報の確認</PageTitle>
 
 	    <div className="rounded-lg border bg-white p-4 dark:border-neutral-700
@@ -279,26 +262,7 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	      </div>
 	    </div>
 
-	    <div className="rounded-lg border bg-white p-4 dark:border-neutral-700
+	    <div className="flex-1 space-y-3 pb-24">
-			    dark:bg-neutral-900">
-	      <div className="flex flex-wrap items-center justify-between gap-3">
-		<div className="text-sm text-neutral-600 dark:text-neutral-300">
-		  URL {rows.length} 件
-		</div>
-		<label className="flex items-center gap-2 text-sm">
-		  <span>既存投稿</span>
-		  <select
-		      value={session.existing}
-		      onChange={ev => updateExisting (ev.target.value as 'skip' | 'error')}
-		      className="rounded border border-border bg-background px-3 py-2">
-		    <option value="skip">スキップ</option>
-		    <option value="error">エラー</option>
-		  </select>
-		</label>
-	      </div>
-	    </div>
-
-	    <div className="space-y-3">
 	      {reviewRows.map (row => (
 		  <div key={row.sourceRow} id={`post-import-row-${ row.sourceRow }`}>
 		    <PostImportRowSummary
@@ -306,16 +270,12 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 			onEdit={() => {
 			    setSearchParams ({ edit: String (row.sourceRow) })
 			}}/>
-		    {rowMessages (row).length > 0 && (
-			<div className="mt-2 md:max-w-3xl">
-			  <FieldError messages={rowMessages (row)}/>
-			</div>)}
 		  </div>))}
 	    </div>
 	  </div>
 
 	  <div
-	      className="fixed inset-x-0 bottom-0 border-t bg-white/95 p-4 backdrop-blur
+	      className="sticky bottom-0 border-t bg-white/95 p-4 backdrop-blur
 			 dark:border-neutral-700 dark:bg-neutral-950/95">
 	    <div className="mx-auto flex max-w-6xl flex-col gap-3 md:flex-row
 			    md:items-center md:justify-between">

frontend/src/pages/posts/PostImportSourcePage.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useMemo, useState } from 'react'
+import { useEffect, useMemo, useRef, useState } from 'react'
 import { Helmet } from 'react-helmet-async'
 import { useNavigate } from 'react-router-dom'
 
@@ -13,11 +13,12 @@ import { apiPost, isApiError } from '@/lib/api'
 import { canEditContent } from '@/lib/users'
 import { inputClass } from '@/lib/utils'
 import { countImportSourceLines,
-	 countImportSourceValidLines,
+	 cleanupExpiredPostImportSessions,
 	 createPostImportSessionId,
 	 loadPostImportSourceDraft,
 	 savePostImportSession,
 	 savePostImportSourceDraft,
+	 validateImportSource,
 	 type PostImportRow } from '@/lib/postImportSession'
 import Forbidden from '@/pages/Forbidden'
 
@@ -33,38 +34,58 @@ const MAX_ROWS = 100
 const PostImportSourcePage: FC<Props> = ({ user }) => {
     const editable = canEditContent (user)
     const navigate = useNavigate ()
-    const draft = useMemo (() => loadPostImportSourceDraft (), [])
+    const draft = useMemo (() => loadPostImportSourceDraft (message =>
+	toast ({ title: '保存済み入力を復元できませんでした', description: message })), [])
 
     const [source, setSource] = useState (draft.source)
-    const [existing, setExisting] = useState<'skip' | 'error'> (draft.existing)
     const [loading, setLoading] = useState (false)
     const [error, setError] = useState<string | null> (null)
+    const [touched, setTouched] = useState (false)
+    const saveTimer = useRef<number | null> (null)
 
     const lineCount = countImportSourceLines (source)
-    const validLineCount = countImportSourceValidLines (source)
+    const issues = useMemo (() => validateImportSource (source), [source])
     const messages = [
-	...(lineCount === 0 ? ['URL を入力してください．'] : []),
+	...(((touched) && lineCount === 0) ? ['URL を入力してください．'] : []),
-	...(lineCount > MAX_ROWS ? [`最大 ${ MAX_ROWS } 件までです．`] : []),
 	...(error ? [error] : [])]
 
     useEffect (() => {
-	savePostImportSourceDraft (source, existing)
+	cleanupExpiredPostImportSessions (message =>
-    }, [existing, source])
+	    toast ({ title: '保存済みデータを整理できませんでした', description: message }))
+    }, [])
+
+    useEffect (() => {
+	if (saveTimer.current != null)
+	  window.clearTimeout (saveTimer.current)
+	saveTimer.current = window.setTimeout (() => {
+	    savePostImportSourceDraft (source, message =>
+		toast ({ title: '入力内容を保存できませんでした', description: message }))
+	}, 300)
+	return () => {
+	    if (saveTimer.current != null)
+	      window.clearTimeout (saveTimer.current)
+	}
+    }, [source])
 
     const preview = async () => {
+	setTouched (true)
+	if (lineCount === 0 || issues.length > 0)
+	  return
+
 	setLoading (true)
 	setError (null)
 	try
 	{
 	    const data = await apiPost<{ rows: PostImportRow[] }> ('/posts/import/preview', {
-		source,
+		source })
-		existing })
 	    const sessionId = createPostImportSessionId ()
-	    savePostImportSession (sessionId, {
+	    const saved = savePostImportSession (sessionId, {
 		source,
-		existing,
 		rows: data.rows,
-		repairMode: 'all' })
+		repairMode: 'all' }, message =>
+		toast ({ title: '取込状態を保存できませんでした', description: message }))
+	    if (!(saved))
+	      return
 	    navigate (`/posts/import/${ sessionId }/review`)
 	}
 	catch (requestError)
@@ -99,48 +120,50 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 	    <div className="rounded-lg border bg-white p-4 dark:border-neutral-700
 			    dark:bg-neutral-900 md:p-6">
 	      <div className="space-y-4">
-		<div className="space-y-2">
-		  <h2 className="text-lg font-semibold">URL リストを入力</h2>
-		  <p className="text-sm text-neutral-600 dark:text-neutral-300">
-		    一行につき一つの URL を入力してください．
-		  </p>
-		</div>
-
 		<FormField label="URL リスト">
 		  {() => (
 		      <textarea
 			  value={source}
 			  rows={14}
 			  className={inputClass (
-			      messages.length > 0,
+			      messages.length > 0 || issues.length > 0,
 			      'font-mono text-sm',
 			  )}
-			  onChange={ev => setSource (ev.target.value)}/>)}
+			  onBlur={() => {
+			      setTouched (true)
+			      savePostImportSourceDraft (source, message =>
+				  toast ({
+				      title: '入力内容を保存できませんでした',
+				      description: message }))
+			  }}
+			  onChange={ev => {
+			      setSource (ev.target.value)
+			      setError (null)
+			  }}/>)}
 		</FormField>
 		<FieldError messages={messages}/>
+		<div className="space-y-2">
+		  {issues.map (issue => (
+		      <div
+			  key={`${ issue.sourceRow }-${ issue.message }-${ issue.url }`}
+			  className="rounded-md border border-red-300 bg-red-50 p-3 text-sm
+				     text-red-700 dark:border-red-900 dark:bg-red-950
+				     dark:text-red-200">
+			<div>{issue.sourceRow} 行目: {issue.message}</div>
+			<div className="mt-1 break-all font-mono text-xs">{issue.url}</div>
+		      </div>))}
+		</div>
 
 		<div className="flex flex-wrap items-center justify-between gap-3 text-sm
 				text-neutral-600 dark:text-neutral-300">
-		  <div>有効行数: {validLineCount}</div>
+		  <div>入力件数 {lineCount} / {MAX_ROWS}</div>
-		  <div>最大 {MAX_ROWS} 件</div>
 		</div>
 
-		<label className="block space-y-1">
-		  <span className="text-sm font-medium">既存投稿</span>
-		  <select
-		      value={existing}
-		      onChange={ev => setExisting (ev.target.value as typeof existing)}
-		      className={inputClass (false, 'w-full md:w-auto')}>
-		    <option value="skip">スキップ</option>
-		    <option value="error">エラー</option>
-		  </select>
-		</label>
-
 		<div className="flex justify-end">
 		  <Button
 		      type="button"
 		      onClick={preview}
-		      disabled={loading || lineCount === 0 || lineCount > MAX_ROWS}>
+		      disabled={loading || lineCount === 0 || issues.length > 0}>
 		    投稿情報を取得
 		  </Button>
 		</div>