#399

frontend/src/lib/postImportSourceValidation.ts

@@ -12,23 +12,14 @@ const bytesize = (value: string): number =>
     new TextEncoder ().encode (value).length
 
 
-const normaliseImportUrl = (value: string): string | null => {
+const parseImportUrl = (value: string): URL | null => {
     const trimmed = value.trim ()
     if (!(trimmed))
       return null
 
     try
     {
-      const url = new URL (trimmed)
+      return 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
     {
@@ -37,12 +28,23 @@ const normaliseImportUrl = (value: string): string | null => {
 }
 
 
-export const countImportSourceLines = (source: string): number =>
+const normaliseImportUrl = (url: URL): string => {
+  url.hostname = url.hostname.toLowerCase ()
+  if (url.pathname.endsWith ('/'))
+    url.pathname = url.pathname.replace (/\/+$/, '')
+  return url.toString ()
+}
+
+
+export const extractImportSourceUrls = (source: string): string[] =>
     source
         .split (/\r\n|\n|\r/)
         .map (line => line.trim ())
         .filter (line => line !== '')
-        .length
+
+
+export const countImportSourceLines = (source: string): number =>
+    extractImportSourceUrls (source).length
 
 
 export const validateImportSource = (
@@ -61,7 +63,6 @@ export const validateImportSource = (
       ++count
       const sourceRow = index + 1
       const displayUrl = truncateUrl (value)
-      const normalised = normaliseImportUrl (value)
       if (count > MAX_ROWS)
         {
           issues.push ({
@@ -70,14 +71,6 @@ export const validateImportSource = (
               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 ({
@@ -86,7 +79,8 @@ export const validateImportSource = (
               url: displayUrl })
           return
         }
-      if (normalised == null)
+      const parsed = parseImportUrl (value)
+      if (parsed == null)
         {
           issues.push ({
               sourceRow,
@@ -94,6 +88,23 @@ export const validateImportSource = (
               url: displayUrl })
           return
         }
+      if (!(parsed.protocol === 'http:' || parsed.protocol === 'https:'))
+        {
+          issues.push ({
+              sourceRow,
+              message: 'HTTP または HTTPS の URL ではありません．',
+              url: displayUrl })
+          return
+        }
+      if (!(parsed.host))
+        {
+          issues.push ({
+              sourceRow,
+              message: 'URL の形式が不正です．',
+              url: displayUrl })
+          return
+        }
+      const normalised = normaliseImportUrl (parsed)
       const duplicateRow = seen.get (normalised)
       if (duplicateRow != null)
         {

frontend/src/lib/postImportStorage.ts

@@ -1,107 +1,6 @@
-import type { PostImportOrigin,
+import type { StorageErrorHandler } from '@/lib/postImportTypes'
-	      PostImportDisplayTag,
-	      PostImportExistingPost,
-	      PostImportResetSnapshot,
-	      PostImportRow,
-	      PostImportSession,
-	      PostImportStatus,
-	      PostImportSkipReason,
-	      StorageErrorHandler } from '@/lib/postImportTypes'
 
-const SESSION_VERSION = 3
-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_SESSION_JSON_BYTES = 262_144
-const MAX_SESSION_ROWS = 100
-const MAX_SOURCE_BYTES = 262_144
-const SESSION_ID_PATTERN =
-    /^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i
-const ATTRIBUTE_KEYS = [
-    'title',
-    'thumbnailBase',
-    'originalCreatedFrom',
-    'originalCreatedBefore',
-    'duration',
-    'videoMs',
-    'tags',
-    'parentPostIds'] as const
-const PROVENANCE_KEYS = [...ATTRIBUTE_KEYS, 'url'] as const
-const TAG_SOURCE_KEYS = ['automatic', 'manual'] as const
-const WARNING_KEYS = [...ATTRIBUTE_KEYS, 'url'] as const
-const ROW_KEYS = [
-    'sourceRow',
-    'url',
-    'attributes',
-    'fieldWarnings',
-    'baseWarnings',
-    'validationErrors',
-    'importErrors',
-    'provenance',
-    'tagSources',
-    'status',
-    'skipReason',
-    'existingPostId',
-    'existingPost',
-    'metadataUrl',
-    'displayTags',
-    'resetSnapshot',
-    'createdPostId',
-    'importStatus',
-    'recoverable'] as const
-const SESSION_KEYS = [
-    'version',
-    'expiresAt',
-    'source',
-    'rows',
-    'repairMode'] as const
-const textEncoder = new TextEncoder ()
-
-
-const isPlainObject = (value: unknown): value is Record<string, unknown> =>
-    typeof value === 'object' && value != null && !(Array.isArray (value))
-
-const byteLength = (value: string): number =>
-    textEncoder.encode (value).byteLength
-
-
-export const validatePostImportSessionId = (value: unknown): string | null => {
-    if (typeof value !== 'string')
-      return null
-    if (value.length > 36 || !(SESSION_ID_PATTERN.test (value)))
-      return null
-
-    return value.toLowerCase ()
-}
-
-
-const generateUuidV4FromRandomValues = (): string => {
-    const bytes = new Uint8Array (16)
-    crypto.getRandomValues (bytes)
-    bytes[6] = (bytes[6] & 0x0f) | 0x40
-    bytes[8] = (bytes[8] & 0x3f) | 0x80
-
-    const hex = Array.from (
-	bytes,
-	byte => byte.toString (16).padStart (2, '0'))
-    return [
-	hex.slice (0, 4).join (''),
-	hex.slice (4, 6).join (''),
-	hex.slice (6, 8).join (''),
-	hex.slice (8, 10).join (''),
-	hex.slice (10, 16).join ('')].join ('-')
-}
-
-
-export const generatePostImportSessionId = (): string => {
-    if (typeof crypto.randomUUID === 'function')
-      return crypto.randomUUID ()
-
-    return generateUuidV4FromRandomValues ()
-}
-
-
-const sessionKey = (sessionId: string): string => `${ SESSION_PREFIX }${ sessionId }`
 
 
 const readStorage = (
@@ -162,531 +61,6 @@ const removeStorage = (
 }
 
 
-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 (item => typeof item === 'string')))
-          return null
-        result[key] = entry
-      }
-    return result
-}
-
-
-const isValidStatus = (
-    value: unknown,
-): value is PostImportRow['status'] =>
-    value === 'pending'
-    || 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 isValidSkipReason = (
-    value: unknown,
-): value is PostImportSkipReason =>
-    value === 'existing' || value === 'manual'
-
-const isPositiveInteger = (value: unknown): value is number =>
-    Number.isSafeInteger (value) && Number (value) > 0
-
-const isNonEmptyMessageRecord = (value: Record<string, string[]>): boolean =>
-    Object.values (value).some (messages => messages.length > 0)
-
-const hasOnlyKeys = (
-    value:        Record<string, unknown>,
-    allowedKeys:  readonly string[],
-): boolean =>
-    Object.keys (value).every (key => allowedKeys.includes (key))
-
-const sanitiseDisplayTag = (value: unknown): PostImportDisplayTag | null => {
-    if (!(isPlainObject (value)))
-      return null
-    if (!(hasOnlyKeys (value, ['name', 'category', 'sectionLiterals'])))
-      return null
-    if (typeof value.name !== 'string' || value.name === '')
-      return null
-    if (typeof value.category !== 'string')
-      return null
-    if (!(['deerjikist',
-	   'meme',
-	   'character',
-	   'general',
-	   'material',
-	   'meta',
-	   'nico'] as const).includes (value.category as never))
-      return null
-    if (value.sectionLiterals != null
-        && (!(Array.isArray (value.sectionLiterals))
-            || !(value.sectionLiterals.every (entry => typeof entry === 'string'))))
-      return null
-
-    return {
-        name: value.name,
-        category: value.category,
-        sectionLiterals:
-            value.sectionLiterals == null
-            ? undefined
-            : [...value.sectionLiterals] }
-}
-
-const sanitiseDisplayTags = (value: unknown): PostImportDisplayTag[] | null => {
-    if (value == null)
-      return []
-    if (!(Array.isArray (value)))
-      return null
-
-    const tags = value.map (sanitiseDisplayTag)
-    return tags.some (tag => tag == null) ? null : (tags as PostImportDisplayTag[])
-}
-
-const sanitiseResetSnapshot = (value: unknown): PostImportResetSnapshot | null => {
-    if (!(isPlainObject (value)))
-      return null
-    if (!(hasOnlyKeys (value, ['url',
-			       'attributes',
-			       'displayTags',
-			       'provenance',
-			       'tagSources',
-			       'fieldWarnings',
-			       'baseWarnings',
-			       'metadataUrl'])))
-      return null
-    if (typeof value.url !== 'string')
-      return null
-    if (!(isPlainObject (value.attributes)))
-      return null
-    if (!(hasOnlyKeys (value.attributes, ATTRIBUTE_KEYS)))
-      return null
-    if (!(Object.values (value.attributes).every (entry =>
-        typeof entry === 'string' || typeof entry === 'number')))
-      return null
-    if (!(isPlainObject (value.provenance)))
-      return null
-    if (!(hasOnlyKeys (value.provenance, PROVENANCE_KEYS)))
-      return null
-    if (!(Object.values (value.provenance).every (origin => isValidOrigin (origin))))
-      return null
-    if (!(isPlainObject (value.tagSources)))
-      return null
-    if (!(hasOnlyKeys (value.tagSources, TAG_SOURCE_KEYS)))
-      return null
-    if (!(Object.values (value.tagSources).every (entry => typeof entry === 'string')))
-      return null
-    const fieldWarnings = ensureStringListRecord (value.fieldWarnings)
-    if (fieldWarnings == null)
-      return null
-    if (!(hasOnlyKeys (fieldWarnings, WARNING_KEYS)))
-      return null
-    if (!(Array.isArray (value.baseWarnings))
-        || !(value.baseWarnings.every (warning => typeof warning === 'string')))
-      return null
-    if (value.metadataUrl != null && typeof value.metadataUrl !== 'string')
-      return null
-    const displayTags = sanitiseDisplayTags (value.displayTags)
-    if (displayTags == null)
-      return null
-
-    return {
-        url: value.url,
-        attributes: value.attributes as Record<string, string | number>,
-        displayTags,
-        provenance: value.provenance as Record<string, PostImportOrigin>,
-        tagSources: value.tagSources as Record<PostImportOrigin, string>,
-        fieldWarnings,
-        baseWarnings: value.baseWarnings,
-        metadataUrl: value.metadataUrl as string | undefined }
-}
-
-const sanitiseExistingPost = (value: unknown): PostImportExistingPost | undefined => {
-    if (value == null)
-      return undefined
-    if (!(isPlainObject (value)))
-      return undefined
-    if (!(isPositiveInteger (value.id)))
-      return undefined
-    if (typeof value.title !== 'string' || typeof value.url !== 'string')
-      return undefined
-    if (value.thumbnail !== undefined
-        && value.thumbnail !== null
-        && typeof value.thumbnail !== 'string')
-      return undefined
-    if (value.thumbnailBase !== undefined
-        && value.thumbnailBase !== null
-        && typeof value.thumbnailBase !== 'string')
-      return undefined
-    if (value.thumbnailUrl !== undefined
-        && value.thumbnailUrl !== null
-        && typeof value.thumbnailUrl !== 'string')
-      return undefined
-
-    return {
-        id: Number (value.id),
-        title: value.title,
-        url: value.url,
-        thumbnail:
-            value.thumbnail === null
-            ? null
-            : typeof value.thumbnail === 'string'
-            ? value.thumbnail
-            : value.thumbnailUrl === null
-              ? null
-              : typeof value.thumbnailUrl === 'string'
-              ? value.thumbnailUrl
-              : undefined,
-        thumbnailBase:
-            value.thumbnailBase === null
-            ? null
-            : typeof value.thumbnailBase === 'string'
-            ? value.thumbnailBase
-            : undefined }
-}
-
-const canonicalisePersistedRow = (
-    row: PostImportRow,
-): PostImportRow | null => {
-    const sanitised = sanitiseRow (serialisePostImportRow (row))
-    return sanitised == null ? null : recalculateThumbnailWarning (sanitised)
-}
-
-const recalculateThumbnailWarning = (row: PostImportRow): PostImportRow => {
-    const others = (row.fieldWarnings.thumbnailBase ?? []).filter (
-	key => key !== 'サムネールなし')
-    const thumbnailBasePresent =
-	typeof row.attributes.thumbnailBase === 'string'
-	&& row.attributes.thumbnailBase.trim () !== ''
-
-    return {
-        ...row,
-        fieldWarnings: {
-	    ...row.fieldWarnings,
-	    thumbnailBase:
-		thumbnailBasePresent
-		? others
-		: [...new Set ([...others, 'サムネールなし'])] } }
-}
-
-const serialiseExistingPost = (value: PostImportExistingPost | undefined) =>
-    value == null
-    ? undefined
-    : {
-	 id: value.id,
-	 title: value.title,
-	 url: value.url,
-	 thumbnail: value.thumbnail,
-	 thumbnailBase: value.thumbnailBase }
-
-const serialiseResetSnapshot = (value: PostImportResetSnapshot) => ({
-    url: value.url,
-    attributes: Object.fromEntries (
-	Object.entries (value.attributes).map (([key, entry]) => [key, entry])),
-    displayTags: value.displayTags.map (tag => ({
-	name: tag.name,
-	category: tag.category,
-	sectionLiterals:
-	    tag.sectionLiterals == null ? undefined : [...tag.sectionLiterals] })),
-    provenance: Object.fromEntries (
-	Object.entries (value.provenance).map (([key, entry]) => [key, entry])),
-    tagSources: {
-	automatic: value.tagSources.automatic,
-	manual: value.tagSources.manual },
-    fieldWarnings: Object.fromEntries (
-	Object.entries (value.fieldWarnings).map (([key, entry]) => [key, [...entry]])),
-    baseWarnings: [...value.baseWarnings],
-    metadataUrl: value.metadataUrl })
-
-export const serialisePostImportRow = (row: PostImportRow) => {
-    const thumbnailBaseWarnings = (() => {
-      const others = (row.fieldWarnings.thumbnailBase ?? []).filter (
-	  message => message !== 'サムネールなし')
-      const thumbnailBasePresent =
-	  typeof row.attributes.thumbnailBase === 'string'
-	  && row.attributes.thumbnailBase.trim () !== ''
-      return thumbnailBasePresent
-	  ? others
-	  : [...new Set ([...others, 'サムネールなし'])]
-    }) ()
-
-    return {
-	sourceRow: row.sourceRow,
-	url: row.url,
-	attributes: Object.fromEntries (
-	    Object.entries (row.attributes).map (([key, entry]) => [key, entry])),
-	fieldWarnings: Object.fromEntries (
-	    Object.entries ({
-		...row.fieldWarnings,
-		thumbnailBase: thumbnailBaseWarnings }).map (([key, entry]) => [key, [...entry]])),
-	baseWarnings: [...row.baseWarnings],
-	validationErrors: Object.fromEntries (
-	    Object.entries (row.validationErrors).map (([key, entry]) => [key, [...entry]])),
-	importErrors:
-	    row.importErrors == null
-	    ? undefined
-	    : Object.fromEntries (
-		Object.entries (row.importErrors).map (([key, entry]) => [key, [...entry]])),
-	provenance: Object.fromEntries (
-	    Object.entries (row.provenance).map (([key, entry]) => [key, entry])),
-	displayTags:
-	    row.displayTags?.map (tag => ({
-		name: tag.name,
-		category: tag.category,
-		sectionLiterals:
-		    tag.sectionLiterals == null ? undefined : [...tag.sectionLiterals] })) ?? [],
-	tagSources:
-	    row.tagSources == null
-	    ? undefined
-	    : {
-		automatic: row.tagSources.automatic,
-		manual: row.tagSources.manual },
-	status: row.status,
-	skipReason: row.skipReason,
-	existingPostId: row.existingPostId,
-	existingPost: serialiseExistingPost (row.existingPost),
-	metadataUrl: row.metadataUrl,
-	resetSnapshot: serialiseResetSnapshot (row.resetSnapshot),
-	createdPostId: row.createdPostId,
-	importStatus: row.importStatus,
-	recoverable: row.recoverable }
-}
-
-export const serialisePostImportRows = (rows: PostImportRow[]) =>
-    rows.map (row => serialisePostImportRow (row))
-
-export const serialisedPostImportRowsEqual = (
-    left:  PostImportRow[],
-    right: PostImportRow[],
-): boolean => {
-    const canonicalLeft = left.map (canonicalisePersistedRow)
-    const canonicalRight = right.map (canonicalisePersistedRow)
-    if (canonicalLeft.some (row => row == null) || canonicalRight.some (row => row == null))
-      return false
-
-    return JSON.stringify (serialisePostImportRows (canonicalLeft as PostImportRow[]))
-        === JSON.stringify (serialisePostImportRows (canonicalRight as PostImportRow[]))
-}
-
-
-const sanitiseRow = (value: unknown): PostImportRow | null => {
-    if (!(isPlainObject (value)))
-      return null
-    if (!(hasOnlyKeys (value, ROW_KEYS)))
-      return null
-    if (!(Number.isInteger (value.sourceRow)) || Number (value.sourceRow) <= 0)
-      return null
-    if (typeof value.url !== 'string')
-      return null
-    if (byteLength (value.url) > 20_480)
-      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
-    if (value.skipReason != null && !(isValidSkipReason (value.skipReason)))
-      return null
-    if (value.recoverable != null && value.recoverable !== true)
-      return null
-    if (value.skipReason === 'existing' && !(isPositiveInteger (value.existingPostId)))
-      return null
-    if (value.importStatus === 'created' && !(isPositiveInteger (value.createdPostId)))
-      return null
-    if (value.importStatus !== 'created' && value.createdPostId != null)
-      return null
-    if (value.recoverable === true
-        && value.importStatus !== 'failed'
-        && value.importStatus !== 'pending')
-      return null
-    if ((value.importStatus === 'created' || value.importStatus === 'skipped')
-        && value.recoverable != null)
-      return null
-
-    const validationErrors = ensureStringListRecord (value.validationErrors)
-    const fieldWarnings = ensureStringListRecord (value.fieldWarnings)
-    const resetSnapshot = sanitiseResetSnapshot (value.resetSnapshot)
-    if (validationErrors == null || fieldWarnings == null)
-      return null
-    if (resetSnapshot == null)
-      return null
-
-    const importErrors =
-        value.importErrors == null
-        ? undefined
-        : ensureStringListRecord (value.importErrors)
-    if (importErrors === null)
-      return null
-    if (!(Array.isArray (value.baseWarnings))
-        || !(value.baseWarnings.every (warning => typeof warning === 'string')))
-      return null
-
-    const provenanceEntries = Object.entries (value.provenance)
-    if (!(hasOnlyKeys (value.attributes, ATTRIBUTE_KEYS)))
-      return null
-    if (!(Object.values (value.attributes).every (entry =>
-        typeof entry === 'string' || typeof entry === 'number')))
-      return null
-    if (!(hasOnlyKeys (value.provenance, PROVENANCE_KEYS)))
-      return null
-    if (!(provenanceEntries.every (([, origin]) => isValidOrigin (origin))))
-      return null
-
-    if (value.tagSources != null)
-      {
-        if (!(isPlainObject (value.tagSources)))
-          return null
-        if (!(hasOnlyKeys (value.tagSources, TAG_SOURCE_KEYS)))
-          return null
-        if (!(Object.values (value.tagSources).every (entry => typeof entry === 'string')))
-          return null
-      }
-    const displayTags = sanitiseDisplayTags (value.displayTags)
-    if (displayTags == null)
-      return null
-
-    const existingPost = sanitiseExistingPost (value.existingPost)
-    const existingPostId =
-        isPositiveInteger (value.existingPostId) ? Number (value.existingPostId) : undefined
-    if (existingPost != null && existingPostId == null)
-      return null
-    if (existingPost != null && existingPost.id !== existingPostId)
-      return null
-
-    return {
-        sourceRow: Number (value.sourceRow),
-        url: value.url,
-        attributes: value.attributes as Record<string, string | number>,
-        fieldWarnings: isNonEmptyMessageRecord (fieldWarnings) ? fieldWarnings : { },
-        baseWarnings: value.baseWarnings,
-        validationErrors: isNonEmptyMessageRecord (validationErrors) ? validationErrors : { },
-        importErrors:
-            importErrors != null && isNonEmptyMessageRecord (importErrors)
-            ? importErrors
-            : undefined,
-        provenance: value.provenance as Record<string, PostImportOrigin>,
-        displayTags,
-        tagSources: value.tagSources as Record<PostImportOrigin, string> | undefined,
-        status: value.status,
-        skipReason: value.skipReason ?? undefined,
-        existingPostId,
-        existingPost,
-        metadataUrl: typeof value.metadataUrl === 'string' ? value.metadataUrl : undefined,
-        resetSnapshot,
-        createdPostId:
-            isPositiveInteger (value.createdPostId) ? Number (value.createdPostId) : undefined,
-        importStatus: value.importStatus ?? undefined,
-        recoverable: value.recoverable === true ? true : undefined }
-}
-
-const sanitiseSession = (value: unknown): PostImportSession | null => {
-    if (!(isPlainObject (value)))
-      return null
-    if (!(hasOnlyKeys (value, SESSION_KEYS)))
-      return null
-    if (value.version !== SESSION_VERSION || !(Array.isArray (value.rows)))
-      return null
-    if (value.rows.length === 0 || value.rows.length > MAX_SESSION_ROWS)
-      return null
-    if (typeof value.expiresAt !== 'string' || isExpiredSession (value.expiresAt))
-      return null
-    if (typeof value.source !== 'string' || byteLength (value.source) > MAX_SOURCE_BYTES)
-      return null
-
-    const rows = value.rows.map (sanitiseRow)
-    if (rows.some (row => row == null))
-      return null
-    if ((new Set (rows.map (row => row?.sourceRow))).size !== rows.length)
-      return null
-
-    return {
-        version: SESSION_VERSION,
-        expiresAt: value.expiresAt,
-        source: value.source,
-        rows: (rows as PostImportRow[]).map (row => recalculateThumbnailWarning (row)),
-        repairMode: value.repairMode === 'failed' ? 'failed' : 'all' }
-}
-
-
-const isExpiredSession = (expiresAt: string): boolean => {
-    const value = Date.parse (expiresAt)
-    return Number.isNaN (value) || value <= Date.now ()
-}
-
-
-export const cleanupExpiredPostImportSessions = (
-    onError?: StorageErrorHandler,
-) => {
-    if (typeof window === 'undefined')
-      return
-
-    try
-    {
-      for (let i = 0; i < sessionStorage.length; ++i)
-        {
-          const key = sessionStorage.key (i)
-          if (key == null || !(key.startsWith (SESSION_PREFIX)))
-            continue
-
-          const sessionId = validatePostImportSessionId (key.slice (SESSION_PREFIX.length))
-          if (sessionId == null)
-            {
-              sessionStorage.removeItem (key)
-              --i
-              continue
-            }
-
-          const raw = sessionStorage.getItem (key)
-          if (raw == null)
-            continue
-          if (byteLength (raw) > MAX_SESSION_JSON_BYTES)
-            {
-              sessionStorage.removeItem (key)
-              --i
-              continue
-            }
-
-          try
-          {
-            if (sanitiseSession (JSON.parse (raw)) == null)
-              {
-                sessionStorage.removeItem (key)
-                --i
-              }
-          }
-          catch
-          {
-            sessionStorage.removeItem (key)
-            --i
-          }
-        }
-    }
-    catch
-    {
-      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 } => {
@@ -718,71 +92,3 @@ export const clearPostImportSourceDraft = (
 ) => {
   removeStorage (SOURCE_DRAFT_KEY, onError)
 }
-
-
-export const savePostImportSession = (
-    sessionId: string,
-    session: Omit<PostImportSession, 'version' | 'expiresAt'>,
-    onError?:  StorageErrorHandler,
-): boolean => {
-    const validatedId = validatePostImportSessionId (sessionId)
-    if (validatedId == null)
-      return false
-
-    return writeStorage (
-        sessionKey (validatedId),
-        JSON.stringify ({
-            source: session.source,
-            rows: serialisePostImportRows (session.rows),
-            repairMode: session.repairMode,
-            version: SESSION_VERSION,
-            expiresAt: new Date (Date.now () + SESSION_MAX_AGE_MS).toISOString () }),
-        onError)
-}
-
-
-export const loadPostImportSession = (
-    sessionId: string,
-    onError?: StorageErrorHandler,
-): PostImportSession | null => {
-    const validatedId = validatePostImportSessionId (sessionId)
-    if (validatedId == null)
-      return null
-
-    const raw = readStorage (sessionKey (validatedId), onError)
-    if (raw == null)
-      return null
-    if (byteLength (raw) > MAX_SESSION_JSON_BYTES)
-      {
-        removeStorage (sessionKey (validatedId), onError)
-        return null
-      }
-
-    try
-    {
-      const session = sanitiseSession (JSON.parse (raw))
-      if (session == null)
-        {
-          removeStorage (sessionKey (validatedId), onError)
-          return null
-        }
-      return session
-    }
-    catch
-    {
-      removeStorage (sessionKey (validatedId), onError)
-      return null
-    }
-}
-
-
-export const clearPostImportSession = (
-    sessionId: string,
-    onError?: StorageErrorHandler,
-) => {
-    const validatedId = validatePostImportSessionId (sessionId)
-    if (validatedId == null)
-      return
-
-    removeStorage (sessionKey (validatedId), onError)
-}

frontend/src/lib/postImportTypes.ts

@@ -79,13 +79,6 @@ export type PostImportResultRow =
 	errors?:   Record<string, string[]>
 	recoverable?: boolean }
 
-export type PostImportSession = {
-    version:     number
-    expiresAt:   string
-    source:      string
-    rows:        PostImportRow[]
-    repairMode:  PostImportRepairMode }
-
 export type PostImportSourceIssue = {
     sourceRow: number
     message:   string

frontend/src/lib/useUnsavedChangesGuard.tsx

@@ -1,6 +1,15 @@
-import { createContext, useCallback, useContext, useMemo, useState } from 'react'
+import {
+    createContext,
+    useCallback,
+    useContext,
+    useEffect,
+    useMemo,
+    useRef,
+    useState,
+} from 'react'
+import { useBlocker, useLocation } from 'react-router-dom'
 
-import { useDialogue } from '@/components/dialogues/DialogueProvider'
+import { useDialogue } from '@/lib/dialogues/useDialogue'
 
 import type { FC, PropsWithChildren } from 'react'
 
@@ -8,12 +17,17 @@ type UnsavedChangesSource = {
     dirty:    boolean
     discard:  () => void | Promise<void> }
 
+type UseUnsavedChangesGuardOptions = {
+    dirty:      boolean
+    onDiscard?: () => void | Promise<void> }
+
 type UnsavedChangesGuardContextValue = {
     hasUnsavedChanges:             boolean
     registerUnsavedChangesSource:  (
 	source: UnsavedChangesSource | null,
     ) => void
-    confirmDiscardNavigation:      () => Promise<boolean> }
+    confirmDiscardNavigation:      () => Promise<boolean>
+    allowNextNavigation:           () => void }
 
 const UnsavedChangesGuardContext =
     createContext<UnsavedChangesGuardContextValue | null> (null)
@@ -21,7 +35,9 @@ const UnsavedChangesGuardContext =
 
 export const UnsavedChangesGuardProvider: FC<PropsWithChildren> = ({ children }) => {
   const dialogue = useDialogue ()
+  const location = useLocation ()
   const [source, setSource] = useState<UnsavedChangesSource | null> (null)
+  const bypassNextNavigationRef = useRef (false)
 
   const registerUnsavedChangesSource = useCallback ((
       nextSource: UnsavedChangesSource | null,
@@ -29,28 +45,81 @@ export const UnsavedChangesGuardProvider: FC<PropsWithChildren> = ({ children })
     setSource (nextSource)
   }, [])
 
+  const allowNextNavigation = useCallback (() => {
+    bypassNextNavigationRef.current = true
+  }, [])
+
   const confirmDiscardNavigation = useCallback (async (): Promise<boolean> => {
     if (!(source?.dirty))
       return true
 
     const confirmed = await dialogue.confirm ({
-	title: '未保存の変更があります',
+	title: '変更が破棄してページ移動しますか?',
-	description: 'このまま移動すると、保存していない変更は失われます。',
-	cancelText: 'このページに残る',
 	confirmText: '変更を破棄して移動',
 	variant: 'danger' })
     if (!(confirmed))
       return false
 
+    bypassNextNavigationRef.current = true
     await source.discard ()
     return true
   }, [dialogue, source])
 
+  const blocker = useBlocker (() =>
+      source?.dirty === true && !(bypassNextNavigationRef.current))
+
+  useEffect (() => {
+    if (blocker.state !== 'blocked')
+      return
+
+    let cancelled = false
+
+    void (async () => {
+      const confirmed = await confirmDiscardNavigation ()
+      if (cancelled)
+	return
+
+      if (confirmed)
+	blocker.proceed ()
+      else
+	blocker.reset ()
+    }) ()
+
+    return () => {
+      cancelled = true
+    }
+  }, [blocker, confirmDiscardNavigation])
+
+  useEffect (() => {
+    bypassNextNavigationRef.current = false
+  }, [location.hash, location.pathname, location.search])
+
+  useEffect (() => {
+    if (!(source?.dirty))
+      return
+
+    const handleBeforeUnload = (event: BeforeUnloadEvent) => {
+      event.preventDefault ()
+      event.returnValue = ''
+    }
+
+    window.addEventListener ('beforeunload', handleBeforeUnload)
+    return () => {
+      window.removeEventListener ('beforeunload', handleBeforeUnload)
+    }
+  }, [source?.dirty])
+
   const value = useMemo<UnsavedChangesGuardContextValue> (() => ({
       hasUnsavedChanges: source?.dirty === true,
       registerUnsavedChangesSource,
       confirmDiscardNavigation,
-  }), [confirmDiscardNavigation, registerUnsavedChangesSource, source?.dirty])
+      allowNextNavigation,
+  }), [
+      allowNextNavigation,
+      confirmDiscardNavigation,
+      registerUnsavedChangesSource,
+      source?.dirty,
+  ])
 
   return (
       <UnsavedChangesGuardContext.Provider value={value}>
@@ -59,11 +128,26 @@ export const UnsavedChangesGuardProvider: FC<PropsWithChildren> = ({ children })
 }
 
 
-export const useUnsavedChangesGuard = (): UnsavedChangesGuardContextValue => {
+export const useUnsavedChangesGuard = (
+    options?: UseUnsavedChangesGuardOptions,
+): UnsavedChangesGuardContextValue => {
   const context = useContext (UnsavedChangesGuardContext)
 
   if (context == null)
     throw new Error ('UnsavedChangesGuardProvider が必要です．')
 
+  useEffect (() => {
+    if (options == null)
+      return
+
+    context.registerUnsavedChangesSource ({
+	dirty: options.dirty,
+	discard: options.onDiscard ?? (() => undefined) })
+
+    return () => {
+      context.registerUnsavedChangesSource (null)
+    }
+  }, [context, options?.dirty, options?.onDiscard])
+
   return context
 }

frontend/src/pages/posts/PostImportReviewPage.tsx

@@ -1,5 +1,5 @@
 import { AnimatePresence, motion } from 'framer-motion'
-import { useEffect, useMemo, useRef, useState } from 'react'
+import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
 import { Helmet } from 'react-helmet-async'
 import { ChevronRight } from 'lucide-react'
 import { useLocation, useNavigate } from 'react-router-dom'
@@ -15,22 +15,16 @@ import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import { apiGet, apiPost, isApiError } from '@/lib/api'
 import useDialogue from '@/lib/dialogues/useDialogue'
-import {
+import { parsePostNewReviewUrls } from '@/lib/postNewQueryState'
-    appendPostNewSessionId,
+import { validateImportSource } from '@/lib/postImportSourceValidation'
-    parsePostNewState,
-    parsePostNewSessionId,
-    serialisePostNewState,
-} from '@/lib/postNewQueryState'
 import {
     applyThumbnailWarning,
     buildNextEditedRow,
     canEditReviewRow,
     canRetryResultRow,
-    clearPostImportSession,
+    compactMessageRecord,
-    clearPostImportSourceDraft,
-    generatePostImportSessionId,
-    hasThumbnailBaseValue,
     hasErrorMessages,
+    hasThumbnailBaseValue,
     isCompletedReviewRow,
     isExistingSkipRow,
     isManualSkipRow,
@@ -42,24 +36,23 @@ import {
     resultRowMessages,
     reviewSummaryCounts,
     retryImportRow,
-    loadPostImportSession,
+} from '@/lib/postImportRows'
-    compactMessageRecord,
+import { clearPostImportSourceDraft } from '@/lib/postImportStorage'
-    serialisedPostImportRowsEqual,
-    savePostImportSession,
-} from '@/lib/postImportSession'
 import { useClientBehaviourSettings } from '@/lib/useClientBehaviourSettings'
+import { useUnsavedChangesGuard } from '@/lib/useUnsavedChangesGuard'
 import { cn } from '@/lib/utils'
 import { canEditContent } from '@/lib/users'
 import Forbidden from '@/pages/Forbidden'
 
 import type { FC } from 'react'
 
-import type { PostImportRowDraft } from '@/components/posts/import/PostImportRowForm'
 import type {
+    PostImportDisplayTag,
+    PostImportEditableDraft,
+    PostImportResetSnapshot,
     PostImportResultRow,
     PostImportRow,
-    PostImportSession,
+} from '@/lib/postImportTypes'
-} from '@/lib/postImportSession'
 import type { User } from '@/types'
 
 type Props = { user: User | null }
@@ -74,7 +67,7 @@ type PostMetadataResponse = {
   duration?:              string
   videoMs?:               number
   tags?:                  string
-  displayTags?:          PostImportRow['displayTags']
+  displayTags?:           PostImportDisplayTag[]
   fieldWarnings?:         Record<string, string[]>
   baseWarnings?:          string[]
   validationErrors?:      Record<string, string[]>
@@ -106,18 +99,101 @@ type ExistingSkippedRowsProps = {
   id:   string
   rows: PostImportRow[] }
 
-const isRepairRow = (row: PostImportRow): boolean =>
-    row.recoverable === true
-    && (row.importStatus === 'failed'
-        || (row.importStatus === 'pending'
-            && hasErrorMessages (row.validationErrors)))
-
 const DUPLICATE_URL_MESSAGE = 'URL が重複しています．'
 const BULK_PROCESSING_FAILED_MESSAGE = '登録中にエラーが発生しました．'
 
+const emptyAttributes = () => ({
+    title: '',
+    thumbnailBase: '',
+    originalCreatedFrom: '',
+    originalCreatedBefore: '',
+    duration: '',
+    videoMs: '',
+    tags: '',
+    parentPostIds: '' })
+
+
+const emptyProvenance = () => ({
+    url: 'manual',
+    title: 'automatic',
+    thumbnailBase: 'automatic',
+    originalCreatedFrom: 'automatic',
+    originalCreatedBefore: 'automatic',
+    duration: 'automatic',
+    videoMs: 'automatic',
+    tags: 'automatic',
+    parentPostIds: 'automatic' }) as const
+
+
+const emptyTagSources = () => ({
+    automatic: '',
+    manual: '' })
+
+
+const cloneDisplayTags = (
+    tags: PostImportDisplayTag[] | undefined,
+): PostImportDisplayTag[] =>
+    tags?.map (tag => ({
+	name: tag.name,
+	category: tag.category,
+	sectionLiterals:
+	    tag.sectionLiterals == null
+	    ? undefined
+	    : [...tag.sectionLiterals] })) ?? []
+
+
+const cloneMessageRecord = (
+    record: Record<string, string[]>,
+): Record<string, string[]> =>
+    Object.fromEntries (
+	Object.entries (record).map (([key, messages]) => [key, [...messages]]))
+
+
+const buildEmptyResetSnapshot = (url: string): PostImportResetSnapshot => ({
+    url,
+    attributes: emptyAttributes (),
+    displayTags: [],
+    provenance: emptyProvenance (),
+    tagSources: emptyTagSources (),
+    fieldWarnings: { },
+    baseWarnings: [] })
+
+
+const buildInitialRows = (urls: string[]): PostImportRow[] => {
+  const source = urls.join ('\n')
+  const issues = validateImportSource (source)
+  const issuesByRow = issues.reduce<Record<number, string[]>> ((result, issue) => {
+    result[issue.sourceRow] = [...(result[issue.sourceRow] ?? []), issue.message]
+    return result
+  }, { })
+
+  return applyDuplicateUrlErrors (
+      urls.map ((url, index) => {
+        const sourceRow = index + 1
+        const rowIssues = issuesByRow[sourceRow] ?? []
+        return {
+            sourceRow,
+            url,
+            attributes: emptyAttributes (),
+            fieldWarnings: { },
+            baseWarnings: [],
+            validationErrors:
+                rowIssues.length > 0
+                ? { url: [...rowIssues] }
+                : { },
+            provenance: emptyProvenance (),
+            tagSources: emptyTagSources (),
+            status: rowIssues.length > 0 ? 'error' : 'pending',
+            displayTags: [],
+            resetSnapshot: buildEmptyResetSnapshot (url) }
+      }))
+}
+
+
 const rowMetadataPending = (row: PostImportRow): boolean =>
     row.status === 'pending'
 
+
 const rowOperationBusy = (
     row:         PostImportRow,
     submitting:  boolean,
@@ -137,6 +213,7 @@ const rowSkipBusy = (
     || busyRowIds.has (row.sourceRow)
     || (rowMetadataPending (row) && !(isManualSkipRow (row)))
 
+
 const shouldFetchMetadata = (row: PostImportRow): boolean =>
     row.status === 'pending'
     && row.skipReason !== 'manual'
@@ -145,6 +222,7 @@ const shouldFetchMetadata = (row: PostImportRow): boolean =>
     && !(isNonRecoverableFailedRow (row))
     && row.metadataUrl == null
 
+
 const shouldHydrateExistingPost = (row: PostImportRow): boolean =>
     row.skipReason === 'existing'
     && row.existingPostId != null
@@ -152,9 +230,11 @@ const shouldHydrateExistingPost = (row: PostImportRow): boolean =>
     && row.importStatus !== 'created'
     && row.importStatus !== 'skipped'
 
+
 const shouldFetchReviewRow = (row: PostImportRow): boolean =>
     shouldFetchMetadata (row) || shouldHydrateExistingPost (row)
 
+
 const applyDuplicateUrlErrors = (
     rows: PostImportRow[],
 ): PostImportRow[] => {
@@ -201,14 +281,6 @@ const applyDuplicateUrlErrors = (
 }
 
 
-const buildSession = (rows: PostImportRow[]): PostImportSession => ({
-    version: 3,
-    expiresAt: '',
-    source: rows.map (row => row.url).join ('\n'),
-    rows,
-    repairMode: resultRepairMode (rows) })
-
-
 const buildDryRunFormData = (row: PostImportRow): FormData => {
   const formData = new FormData ()
   formData.append ('url', row.url)
@@ -238,6 +310,7 @@ const mergeDryRunRow = (
   const hasWarnings =
       Object.values (fieldWarnings).some (messages => messages.length > 0)
       || (result.baseWarnings?.length ?? 0) > 0
+
   return applyThumbnailWarning ({
       ...currentRow,
       url: result.url,
@@ -250,23 +323,14 @@ const mergeDryRunRow = (
 	  duration: result.duration ?? '',
 	  videoMs: result.videoMs ?? '',
 	  tags: result.tags ?? '',
-            parentPostIds: String (result.parentPostIds ?? currentRow.attributes.parentPostIds ?? '') },
+	  parentPostIds: String (
-        displayTags:
+	      result.parentPostIds ?? currentRow.attributes.parentPostIds ?? '') },
-            result.displayTags?.map (tag => ({
+      displayTags: cloneDisplayTags (result.displayTags),
-                name: tag.name,
-                category: tag.category,
-                sectionLiterals:
-                    tag.sectionLiterals == null
-                    ? undefined
-                    : [...tag.sectionLiterals] })) ?? [],
       fieldWarnings,
       baseWarnings: result.baseWarnings ?? [],
       validationErrors: { },
       importErrors: undefined,
-        status:
+      status: hasWarnings ? 'warning' : 'ready',
-            hasWarnings
-            ? 'warning'
-            : 'ready',
       skipReason:
 	  result.existingPostId != null || result.existingPost?.id != null
 	  ? 'existing'
@@ -294,24 +358,8 @@ const buildPreviewResetSnapshot = (
 	videoMs: preview.videoMs ?? '',
 	tags: preview.tags ?? '',
 	parentPostIds: String (preview.parentPostIds ?? '') },
-    displayTags:
+    displayTags: cloneDisplayTags (preview.displayTags),
-	preview.displayTags?.map (tag => ({
+    provenance: emptyProvenance (),
-	    name: tag.name,
-	    category: tag.category,
-	    sectionLiterals:
-		tag.sectionLiterals == null
-		? undefined
-		: [...tag.sectionLiterals] })) ?? [],
-    provenance: {
-	url: 'manual',
-	title: 'automatic',
-	thumbnailBase: 'automatic',
-	originalCreatedFrom: 'automatic',
-	originalCreatedBefore: 'automatic',
-	duration: 'automatic',
-	videoMs: 'automatic',
-	tags: 'automatic',
-	parentPostIds: 'automatic' },
     tagSources: {
 	automatic: preview.tags ?? '',
 	manual: '' },
@@ -358,8 +406,7 @@ const indexedBulkResults = (
                   errors: {
                       ...(errors ?? { }),
                       base: [...new Set ([...(errors?.base ?? []),
-                                          BULK_PROCESSING_FAILED_MESSAGE])],
+					  BULK_PROCESSING_FAILED_MESSAGE])] },
-                  },
                   recoverable: false }
             }
           return {
@@ -380,6 +427,7 @@ const indexedBulkResults = (
           recoverable: result?.recoverable }
     })
 
+
 const mergePreviewRow = (
     currentRow: PostImportRow,
     preview:    PostMetadataResponse,
@@ -397,14 +445,7 @@ const mergePreviewRow = (
       ...currentRow,
       attributes: { ...currentRow.attributes },
       provenance: { ...currentRow.provenance },
-      displayTags:
+      displayTags: cloneDisplayTags (currentRow.displayTags),
-	  currentRow.displayTags?.map (tag => ({
-	      name: tag.name,
-	      category: tag.category,
-	      sectionLiterals:
-		  tag.sectionLiterals == null
-		  ? undefined
-		  : [...tag.sectionLiterals] })) ?? [],
       tagSources: {
 	  automatic: currentRow.tagSources?.automatic ?? '',
 	  manual: currentRow.tagSources?.manual ?? '' },
@@ -443,14 +484,7 @@ const mergePreviewRow = (
   if (currentRow.provenance.tags !== 'manual')
     {
       nextRow.attributes.tags = preview.tags ?? ''
-      nextRow.displayTags =
+      nextRow.displayTags = cloneDisplayTags (preview.displayTags)
-	  preview.displayTags?.map (tag => ({
-	      name: tag.name,
-	      category: tag.category,
-	      sectionLiterals:
-		  tag.sectionLiterals == null
-		  ? undefined
-		  : [...tag.sectionLiterals] })) ?? []
     }
   nextRow.tagSources.automatic = preview.tags ?? ''
   if (currentRow.provenance.parentPostIds !== 'manual')
@@ -547,6 +581,26 @@ const ExistingSkippedRows: FC<ExistingSkippedRowsProps> = ({ id, rows }) => {
 }
 
 
+const editableRowDirty = (row: PostImportRow): boolean =>
+    row.skipReason === 'manual'
+    || row.url !== row.resetSnapshot.url
+    || String (row.attributes.title ?? '')
+        !== String (row.resetSnapshot.attributes.title ?? '')
+    || String (row.attributes.thumbnailBase ?? '')
+        !== String (row.resetSnapshot.attributes.thumbnailBase ?? '')
+    || String (row.attributes.originalCreatedFrom ?? '')
+        !== String (row.resetSnapshot.attributes.originalCreatedFrom ?? '')
+    || String (row.attributes.originalCreatedBefore ?? '')
+        !== String (row.resetSnapshot.attributes.originalCreatedBefore ?? '')
+    || String (row.attributes.duration ?? '')
+        !== String (row.resetSnapshot.attributes.duration ?? '')
+    || String (row.attributes.tags ?? '')
+        !== String (row.resetSnapshot.attributes.tags ?? '')
+    || String (row.attributes.parentPostIds ?? '')
+        !== String (row.resetSnapshot.attributes.parentPostIds ?? '')
+    || row.thumbnailFile != null
+
+
 const PostImportReviewPage: FC<Props> = ({ user }) => {
   const editable = canEditContent (user)
   const dialogue = useDialogue ()
@@ -561,146 +615,101 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	? { duration: .08, ease: 'linear' as const }
 	: { duration: .2, ease: 'easeOut' as const }
 
-  const [session, setSession] = useState<PostImportSession | null> (null)
+  const [rows, setRows] = useState<PostImportRow[] | null> (null)
   const [metadataLoading, setMetadataLoading] = useState (false)
   const [submitting, setSubmitting] = useState (false)
   const [busyRowIds, setBusyRowIds] = useState<Set<number>> (new Set ())
   const [editingRow, setEditingRow] = useState<PostImportRow | null> (null)
   const [showExistingRows, setShowExistingRows] = useState (false)
-  const sessionRef = useRef<PostImportSession | null> (null)
+  const rowsRef = useRef<PostImportRow[]> ([])
-  const sessionIdRef = useRef<string | null> (null)
-  const persistedSearchRef = useRef<string | null> (null)
-  const persistSequenceRef = useRef (0)
-  const previewSequenceRef = useRef (0)
   const metadataSequenceRef = useRef (0)
+  const discardChanges = useCallback (() => undefined, [])
 
-  const showStorageError = (message: string) =>
+  const dirty = useMemo (
-      toast ({ description: message })
+      () => rows?.some (row => editableRowDirty (row)) ?? false,
+      [rows],
+  )
+  const { allowNextNavigation } = useUnsavedChangesGuard ({
+      dirty,
+      onDiscard: discardChanges,
+  })
 
-  const commitSessionState = (
+  const commitRows = useCallback ((nextRows: PostImportRow[]) => {
-      nextSession: PostImportSession,
+    rowsRef.current = nextRows
-  ): {
+    setRows (nextRows)
-      session:                    PostImportSession
+    return nextRows
-      sessionRoundTripSucceeded:  boolean } => {
+  }, [])
-    const sessionId =
-	sessionIdRef.current ?? generatePostImportSessionId ()
-    sessionIdRef.current = sessionId
-    const persistedSession = buildSession (nextSession.rows)
-    const saved = savePostImportSession (sessionId, persistedSession, showStorageError)
-    const loadedSession =
-	saved
-	? loadPostImportSession (sessionId, showStorageError)
-	: null
-    sessionRef.current = persistedSession
-    setSession (persistedSession)
-    return {
-	session: persistedSession,
-	sessionRoundTripSucceeded:
-	    saved
-	    && serialisedPostImportRowsEqual (
-		loadedSession?.rows ?? [],
-		persistedSession.rows) }
-  }
 
-  const syncSessionUrl = async (
+  const updateRows = useCallback ((
-      nextSession: PostImportSession,
+      updater: (currentRows: PostImportRow[]) => PostImportRow[],
-  ): Promise<PostImportSession | null> => {
+  ) => {
-    const sessionId =
+    const nextRows = applyDuplicateUrlErrors (updater (rowsRef.current))
-	sessionIdRef.current ?? generatePostImportSessionId ()
+    return commitRows (nextRows)
-    sessionIdRef.current = sessionId
+  }, [commitRows])
-    const sequence = ++persistSequenceRef.current
-    const serialised = await serialisePostNewState (nextSession.rows)
-    if (serialised == null)
-      return null
-    if (persistSequenceRef.current !== sequence)
-      return null
 
-    const { session: persistedSession,
+  const currentRowBySource = useCallback ((
-	    sessionRoundTripSucceeded } = commitSessionState (nextSession)
-    const canNavigate =
-	serialised.complete
-	|| sessionRoundTripSucceeded
-    if (!(canNavigate))
-      {
-	showStorageError ('ブラウザへ保存できませんでした．')
-	return null
-      }
-
-    const path = appendPostNewSessionId (serialised.path, sessionId)
-    persistedSearchRef.current = (new URL (path, window.location.origin)).search
-    navigate (path, { replace: true })
-    return persistedSession
-  }
-
-  const currentRowBySource = (
       sourceRow: number,
-      fallback?: PostImportSession,
   ): PostImportRow | null =>
-      (sessionRef.current?.rows ?? fallback?.rows ?? []).find (
+      rowsRef.current.find (row => row.sourceRow === sourceRow) ?? null,
-	  row => row.sourceRow === sourceRow) ?? null
+  [])
 
-  const finishImport = () => {
+  const finishImport = useCallback (() => {
-    const sessionId = sessionIdRef.current
+    allowNextNavigation ()
-    if (sessionId != null)
-      clearPostImportSession (sessionId)
     clearPostImportSourceDraft (message =>
 	toast ({ title: '入力内容を削除できませんでした', description: message }))
     navigate ('/posts')
-  }
+  }, [allowNextNavigation, navigate])
 
   useEffect (() => {
+    const urls = parsePostNewReviewUrls (location.search)
+    const initialRows = buildInitialRows (urls)
+    commitRows (initialRows)
+
     let active = true
-    const previewSequence = ++previewSequenceRef.current
+    const sequence = ++metadataSequenceRef.current
-    metadataSequenceRef.current = previewSequence
     const controllers = new Set<AbortController> ()
-
-    if (sessionRef.current != null
-        && persistedSearchRef.current === location.search
-        && !(sessionRef.current.rows.some (row => shouldFetchReviewRow (row))))
-      return () => {
-        previewSequenceRef.current = previewSequence
-      }
-
-    const refreshRows = async (baseSession: PostImportSession) => {
-      const blocksSubmit = baseSession.rows.some (row => shouldFetchMetadata (row))
-      if (active && blocksSubmit)
-	setMetadataLoading (true)
-      try
-      {
     let nextIndex = 0
+    const targetSourceRows = initialRows
+        .filter (row => shouldFetchReviewRow (row))
+        .map (row => row.sourceRow)
+
+    setMetadataLoading (targetSourceRows.length > 0)
+
     const mergeCurrentRow = (
 	sourceRow: number,
 	updater:   (row: PostImportRow) => PostImportRow,
     ) => {
-	    const latestRows = sessionRef.current?.rows ?? baseSession.rows
+      updateRows (currentRows =>
-	    const nextRows = applyDuplicateUrlErrors (latestRows.map (row =>
+	  currentRows.map (row =>
 	      row.sourceRow === sourceRow
 	      ? updater (row)
 	      : row))
-	    commitSessionState (buildSession (nextRows))
     }
+
     const worker = async () => {
       while (active)
 	{
-            const index = nextIndex
+	  const sourceRow = targetSourceRows[nextIndex]
 	  ++nextIndex
-            if (index >= baseSession.rows.length)
+	  if (sourceRow == null)
 	    return
 
-            const baseRow = baseSession.rows[index]
+	  const currentRow = currentRowBySource (sourceRow)
-            const currentRow = currentRowBySource (baseRow.sourceRow, baseSession)
 	  if (currentRow == null || !(shouldFetchReviewRow (currentRow)))
 	    continue
+
 	  const controller = new AbortController ()
 	  controllers.add (controller)
+
 	  try
 	  {
 	    const preview = await apiGet<PostMetadataResponse> ('/posts/metadata', {
 		params: { url: currentRow.url },
 		signal: controller.signal })
-              if (!(active) || previewSequenceRef.current !== previewSequence)
+	    if (!(active) || metadataSequenceRef.current !== sequence)
 	      return
-              mergeCurrentRow (currentRow.sourceRow, row =>
+
+	    mergeCurrentRow (sourceRow, row =>
 		row.importStatus === 'created'
 		|| row.importStatus === 'skipped'
 		|| isNonRecoverableFailedRow (row)
@@ -714,18 +723,20 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	  {
 	    if (controller.signal.aborted)
 	      return
-              if (!(active) || previewSequenceRef.current !== previewSequence)
+	    if (!(active) || metadataSequenceRef.current !== sequence)
 	      return
+
 	    if (!(isApiError<{
 		    errors?:     Record<string, string[]>
 		    baseErrors?: string[]
 		}> (requestError)))
 	      {
-                  mergeCurrentRow (currentRow.sourceRow, row => ({
+		mergeCurrentRow (sourceRow, row => ({
 		    ...row,
 		    status: 'error' }))
 		continue
 	      }
+
 	    if (requestError.response?.status === 422)
 	      {
 		const rowErrors = compactMessageRecord ({
@@ -734,16 +745,18 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 			? {
 			    base: requestError.response.data.baseErrors }
 			: { }) })
-                  mergeCurrentRow (currentRow.sourceRow, row => ({
+		mergeCurrentRow (sourceRow, row => ({
 		    ...row,
 		    validationErrors: rowErrors,
 		    status: 'error' }))
 	      }
 	    else
-                mergeCurrentRow (currentRow.sourceRow, row => ({
+	      {
+		mergeCurrentRow (sourceRow, row => ({
 		    ...row,
 		    status: 'error' }))
 	      }
+	  }
 	  finally
 	  {
 	    controllers.delete (controller)
@@ -751,99 +764,71 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	}
     }
 
-        await Promise.all (
+    void Promise.all (
-            Array.from ({ length: Math.min (4, baseSession.rows.length) }, () => worker ()))
+	Array.from (
-        if (!(active) || previewSequenceRef.current !== previewSequence)
+	    { length: Math.min (4, targetSourceRows.length) },
-          return
+	    () => worker (),
-
+	)).finally (() => {
-        const latestRows = sessionRef.current?.rows ?? baseSession.rows
+	  if (active && metadataSequenceRef.current === sequence)
-        const nextRows = applyDuplicateUrlErrors (latestRows)
-        await syncSessionUrl (buildSession (nextRows))
-      }
-      finally
-      {
-        if (active
-	    && blocksSubmit
-	    && metadataSequenceRef.current === previewSequence)
 	    setMetadataLoading (false)
-      }
+	})
-    }
-
-    const hydrate = async () => {
-      const parsedSessionId = parsePostNewSessionId (location.search)
-      const sessionId = parsedSessionId ?? generatePostImportSessionId ()
-      const loadedSession = loadPostImportSession (sessionId)
-      const parsed = await parsePostNewState (location.search)
-      if (!(active))
-	return
-      if (parsed == null && loadedSession == null)
-	{
-	  setMetadataLoading (false)
-	  navigate ('/posts/new', { replace: true })
-	  return
-	}
-
-      sessionIdRef.current = sessionId
-      const loaded = loadedSession ?? buildSession (parsed?.rows ?? [])
-      persistedSearchRef.current = location.search
-      sessionRef.current = loaded
-      setSession (loaded)
-
-      void refreshRows (loaded)
-    }
-
-    void hydrate ()
 
     return () => {
       active = false
       controllers.forEach (controller => controller.abort ())
     }
-  }, [location.search, navigate])
+  }, [commitRows, currentRowBySource, location.search, updateRows])
 
   useEffect (() => {
-    if (session != null)
+    if (editingRow == null || resultRepairMode (rowsRef.current) !== 'failed')
-      sessionRef.current = session
-  }, [session])
-
-  useEffect (() => {
-    if (editingRow == null || session?.repairMode !== 'failed')
       return
 
     const element = document.getElementById (`post-import-row-${ editingRow.sourceRow }`)
     element?.scrollIntoView ({ block: 'center', behavior: 'smooth' })
-  }, [editingRow, session?.repairMode])
+  }, [editingRow, rows])
 
-  const rows = session?.rows ?? []
+  const reviewRowsState = rows ?? []
-  const counts = useMemo (() => reviewSummaryCounts (rows), [rows])
+  const counts = useMemo (
+      () => reviewSummaryCounts (reviewRowsState),
+      [reviewRowsState],
+  )
   const sortedRows =
-      session?.repairMode === 'failed'
+      resultRepairMode (reviewRowsState) === 'failed'
-      ? (
+      ? [...reviewRowsState].sort ((a, b) => {
-	  [...rows].sort ((a, b) => {
+	  const aRepair =
-	    const aRepair = isRepairRow (a) ? 0 : 1
+	      a.recoverable === true
-	    const bRepair = isRepairRow (b) ? 0 : 1
+	      && (a.importStatus === 'failed'
+		  || (a.importStatus === 'pending'
+		      && hasErrorMessages (a.validationErrors)))
+	      ? 0
+	      : 1
+	  const bRepair =
+	      b.recoverable === true
+	      && (b.importStatus === 'failed'
+		  || (b.importStatus === 'pending'
+		      && hasErrorMessages (b.validationErrors)))
+	      ? 0
+	      : 1
 	  return aRepair - bRepair || a.sourceRow - b.sourceRow
-	  }))
+      })
-      : rows
+      : reviewRowsState
   const existingRows = sortedRows.filter (row => isExistingSkipRow (row))
   const reviewRows = sortedRows.filter (row => !(isExistingSkipRow (row)))
-  const processingRows = processableImportRows (rows)
+  const processingRows = processableImportRows (reviewRowsState)
   const canSubmit = processingRows.length > 0
 
   const toggleManualSkip = async (sourceRow: number, checked: boolean) => {
-    const currentSession = sessionRef.current
+    const currentRow = currentRowBySource (sourceRow)
-    if (currentSession == null)
-      return
-    const currentRow = currentRowBySource (sourceRow, currentSession)
     if (currentRow == null)
       return
     if (rowSkipBusy (currentRow, submitting, busyRowIds))
       return
 
-    const nextRows = currentSession.rows.map (row => {
+    updateRows (currentRows =>
+	currentRows.map (row => {
 	  if (row.sourceRow !== sourceRow)
 	    return row
-      if (isExistingSkipRow (row)
+	  if (isExistingSkipRow (row) || row.importStatus === 'created')
-          || row.importStatus === 'created')
 	    return row
 	  return {
 	      ...row,
@@ -853,27 +838,17 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 		  : row.existingPostId != null
 		    ? 'existing'
 		    : undefined }
-    })
+	}))
-    const nextSession = buildSession (applyDuplicateUrlErrors (nextRows))
-    if (metadataLoading)
-      {
-        commitSessionState (nextSession)
-        return
-      }
-    await syncSessionUrl (nextSession)
   }
 
   const saveDraft = async (
       row: PostImportRow,
       { draft, resetRequested }: {
-	  draft:          PostImportRowDraft
+	  draft:          PostImportEditableDraft
 	  resetRequested: boolean },
   ): Promise<{ saved: boolean
 	       row:   PostImportRow | null }> => {
-    const currentSession = sessionRef.current
+    const currentRow = currentRowBySource (row.sourceRow)
-    if (currentSession == null)
-      return { saved: false, row: null }
-    const currentRow = currentRowBySource (row.sourceRow, currentSession)
     if (currentRow == null)
       return { saved: false, row: null }
     if (!(canEditReviewRow (currentRow)))
@@ -881,22 +856,14 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 
     const baseRow =
 	resetRequested
-	? { ...currentRow,
+	? {
+	    ...currentRow,
 	    url: currentRow.resetSnapshot.url,
 	    attributes: { ...currentRow.resetSnapshot.attributes },
-	    displayTags:
+	    displayTags: cloneDisplayTags (currentRow.resetSnapshot.displayTags),
-		currentRow.resetSnapshot.displayTags.map (tag => ({
-		    name: tag.name,
-		    category: tag.category,
-		    sectionLiterals:
-			tag.sectionLiterals == null
-			? undefined
-			: [...tag.sectionLiterals] })),
 	    provenance: { ...currentRow.resetSnapshot.provenance },
 	    tagSources: { ...currentRow.resetSnapshot.tagSources },
-	    fieldWarnings: Object.fromEntries (
+	    fieldWarnings: cloneMessageRecord (currentRow.resetSnapshot.fieldWarnings),
-		Object.entries (currentRow.resetSnapshot.fieldWarnings)
-		    .map (([key, values]) => [key, [...values]])),
 	    baseWarnings: [...currentRow.resetSnapshot.baseWarnings],
 	    metadataUrl: currentRow.resetSnapshot.metadataUrl,
 	    thumbnailFile: undefined }
@@ -904,6 +871,7 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
     const urlChanged = draft.url !== baseRow.url
     const nextRow = buildNextEditedRow (baseRow, draft, urlChanged)
     let candidateRow = nextRow
+
     try
     {
       candidateRow =
@@ -916,21 +884,11 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
       const dryRun = await apiPost<PostMetadataResponse> (
 	  '/posts?dry=1',
 	  buildDryRunFormData (candidateRow))
-      const latestSession = sessionRef.current
-      if (latestSession == null)
-	return { saved: false, row: null }
-
       const mergedRow = mergeDryRunRow (candidateRow, dryRun)
-      const mergedRows = applyDuplicateUrlErrors (
+      const mergedRows = updateRows (currentRows =>
-	  replaceImportRow (latestSession.rows, mergedRow))
+	  replaceImportRow (currentRows, mergedRow))
-      const nextSession =
+      const mergedTarget = mergedRows.find (
-	  metadataLoading
+	  current => current.sourceRow === baseRow.sourceRow)
-	  ? commitSessionState (buildSession (mergedRows)).session
-	  : await syncSessionUrl (buildSession (mergedRows))
-      if (nextSession == null)
-	return { saved: false, row: null }
-      const mergedTarget = nextSession.rows.find (
-	  currentRow => currentRow.sourceRow === baseRow.sourceRow)
       if (mergedTarget == null)
 	return { saved: false, row: null }
       if (hasErrorMessages (mergedTarget.validationErrors))
@@ -967,7 +925,7 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
   const openEditingDialogue = async (row: PostImportRow) => {
     const saveRowDraft = (
 	{ draft, resetRequested }: {
-	    draft:          PostImportRowDraft
+	    draft:          PostImportEditableDraft
 	    resetRequested: boolean },
     ) =>
 	saveDraft (row, { draft, resetRequested })
@@ -984,8 +942,7 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
   }
 
   const editRow = async (row: PostImportRow) => {
-    const currentRow = sessionRef.current?.rows.find (
+    const currentRow = currentRowBySource (row.sourceRow)
-	current => current.sourceRow === row.sourceRow)
     if (currentRow == null)
       return
     if (!(canEditReviewRow (currentRow)))
@@ -1008,11 +965,7 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
   }
 
   const retry = async (sourceRow: number) => {
-    const initialSession = sessionRef.current
+    const originalRow = currentRowBySource (sourceRow)
-    if (initialSession == null)
-      return
-
-    const originalRow = initialSession.rows.find (row => row.sourceRow === sourceRow)
     if (originalRow == null)
       return
     if (rowOperationBusy (originalRow, submitting, busyRowIds))
@@ -1021,15 +974,8 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
     setBusyRowIds (current => new Set ([...current, sourceRow]))
     try
     {
-      const pendingRows = retryImportRow (initialSession.rows, sourceRow)
+      updateRows (currentRows => retryImportRow (currentRows, sourceRow))
-      const pendingSession =
+      const target = currentRowBySource (sourceRow)
-	  metadataLoading
-	  ? commitSessionState (buildSession (pendingRows)).session
-	  : await syncSessionUrl (buildSession (pendingRows))
-      if (pendingSession == null)
-	return
-
-      const target = pendingSession.rows.find (row => row.sourceRow === sourceRow)
       if (target == null)
 	return
 
@@ -1038,37 +984,22 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	  buildBulkFormData ([target]))
       if (result.results.length !== 1)
 	{
-	  const latest = sessionRef.current ?? pendingSession
+	  updateRows (currentRows => replaceImportRow (currentRows, originalRow))
-	  const restoredRows = replaceImportRow (latest.rows, originalRow)
-	  if (metadataLoading)
-	    commitSessionState (buildSession (restoredRows))
-	  else
-	    await syncSessionUrl (buildSession (restoredRows))
 	  toast ({ title: '登録結果が不完全でした' })
 	  return
 	}
 
       const indexedResults = indexedBulkResults ([target], result.results)
-      const latestAfterImport = sessionRef.current ?? pendingSession
       const nextRows = applyDuplicateUrlErrors (
-	  mergeImportResults (latestAfterImport.rows, indexedResults))
+	  mergeImportResults (rowsRef.current, indexedResults))
 	  .map (row => applyThumbnailWarning (row))
-      const persisted =
+      commitRows (nextRows)
-	  metadataLoading
+      if (nextRows.every (row => isCompletedReviewRow (row)))
-	  ? commitSessionState (buildSession (nextRows)).session
-	  : await syncSessionUrl (buildSession (nextRows))
-      if (persisted != null
-	  && persisted.rows.every (row => isCompletedReviewRow (row)))
 	finishImport ()
     }
     catch
     {
-      const latest = sessionRef.current ?? initialSession
+      updateRows (currentRows => replaceImportRow (currentRows, originalRow))
-      const restoredRows = replaceImportRow (latest.rows, originalRow)
-      if (metadataLoading)
-	commitSessionState (buildSession (restoredRows))
-      else
-	await syncSessionUrl (buildSession (restoredRows))
       toast ({ title: '再試行に失敗しました' })
     }
     finally
@@ -1082,14 +1013,11 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
   }
 
   const submit = async () => {
-    const currentSession = sessionRef.current
+    if (metadataLoading || submitting || busyRowIds.size > 0)
-    if (currentSession == null
-	|| metadataLoading
-	|| submitting
-	|| busyRowIds.size > 0)
       return
-    const processingRows = processableImportRows (currentSession.rows)
+
-    if (processingRows.length === 0)
+    const latestProcessingRows = processableImportRows (rowsRef.current)
+    if (latestProcessingRows.length === 0)
       return
 
     setSubmitting (true)
@@ -1097,21 +1025,19 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
     {
       const result = await apiPost<{ results: BulkApiRow[] }>(
 	  '/posts/bulk',
-	  buildBulkFormData (processingRows))
+	  buildBulkFormData (latestProcessingRows))
-      if (result.results.length !== processingRows.length)
+      if (result.results.length !== latestProcessingRows.length)
 	{
 	  toast ({ title: '登録結果が不完全でした' })
 	  return
 	}
 
-      const indexedResults = indexedBulkResults (processingRows, result.results)
+      const indexedResults = indexedBulkResults (latestProcessingRows, result.results)
-      const latestAfterImport = sessionRef.current ?? buildSession (currentSession.rows)
       const nextRows = applyDuplicateUrlErrors (
-	  mergeImportResults (latestAfterImport.rows, indexedResults))
+	  mergeImportResults (rowsRef.current, indexedResults))
 	  .map (row => applyThumbnailWarning (row))
-      const persisted = await syncSessionUrl (buildSession (nextRows))
+      commitRows (nextRows)
-      if (persisted != null
+      if (nextRows.every (row => isCompletedReviewRow (row)))
-	  && persisted.rows.every (row => isCompletedReviewRow (row)))
 	finishImport ()
     }
     catch
@@ -1127,7 +1053,7 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
   if (!(editable))
     return <Forbidden/>
 
-  if (session == null)
+  if (rows == null)
     return null
 
   return (
@@ -1136,11 +1062,11 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	  <title>{`追加内容確認 | ${ SITE_TITLE }`}</title>
 	</Helmet>
 
-	<MainArea className="min-h-0">
+	<MainArea className="pb-40">
-	  <div className="mx-auto max-w-6xl space-y-4 p-4">
+	  <div className="mx-auto max-w-6xl space-y-6">
 	    <PageTitle>追加内容確認</PageTitle>
 
-	    {counts.existingSkipped > 0 && (
+	    {existingRows.length > 0 && (
 		<div className="rounded-lg border p-4">
 		  <button
 		      type="button"
@@ -1209,13 +1135,12 @@ const PostImportReviewPage: FC<Props> = ({ user }) => {
 	    manualSkippedCount={counts.manualSkipped}
 	    existingSkippedCount={counts.existingSkipped}
 	    pendingOrErrorCount={counts.pendingOrError}
-	    onBack={() => navigate (location.state?.from === '/posts/new'
+	    onBack={() => navigate ('/posts/new')}
-				    ? '/posts/new'
-				    : (-1))}
 	    onSubmit={() => submit ()}/>
       </>)
 }
 
+
 const PostImportFooter = (
     { metadataLoading,
       submitting,

frontend/src/pages/posts/PostImportSourcePage.tsx

@@ -12,26 +12,23 @@ import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
 import {
-    appendPostNewSessionId,
+    buildPostNewReviewPath,
-    serialisePostNewState,
+    isPostNewReviewPathWithinLimit,
 } from '@/lib/postNewQueryState'
-import { canEditContent } from '@/lib/users'
+import {
-import { countImportSourceLines,
+    countImportSourceLines,
-	 generatePostImportSessionId,
+    extractImportSourceUrls,
-	 cleanupExpiredPostImportSessions,
+    validateImportSource,
-	 initialisePreviewRows,
+} from '@/lib/postImportSourceValidation'
-	 loadPostImportSession,
+import {
     loadPostImportSourceDraft,
-	 resultRepairMode,
-	 serialisedPostImportRowsEqual,
-	 savePostImportSession,
     savePostImportSourceDraft,
-	 validateImportSource } from '@/lib/postImportSession'
+} from '@/lib/postImportStorage'
+import { canEditContent } from '@/lib/users'
 import Forbidden from '@/pages/Forbidden'
 
 import type { FC } from 'react'
 
-import type { PostImportRow } from '@/lib/postImportSession'
 import type { User } from '@/types'
 
 type Props = { user: User | null }
@@ -40,71 +37,6 @@ const MAX_ROWS = 100
 const SOURCE_ERROR_ID = 'post-import-source-error'
 const SOURCE_ISSUES_ID = 'post-import-source-issues'
 
-const buildInitialRows = (source: string): PostImportRow[] =>
-    source
-        .split (/\r\n|\n|\r/)
-        .map ((line, index) => ({
-            sourceRow: index + 1,
-            url: line.trim () }))
-        .filter (row => row.url !== '')
-        .map (row => ({
-            sourceRow: row.sourceRow,
-            url: row.url,
-            attributes: {
-                title: '',
-                thumbnailBase: '',
-                originalCreatedFrom: '',
-                originalCreatedBefore: '',
-                duration: '',
-                videoMs: '',
-                tags: '',
-                parentPostIds: '' },
-            fieldWarnings: { },
-            baseWarnings: [],
-            validationErrors: { },
-            provenance: {
-                url: 'manual',
-                title: 'automatic',
-                thumbnailBase: 'automatic',
-                originalCreatedFrom: 'automatic',
-                originalCreatedBefore: 'automatic',
-                duration: 'automatic',
-                videoMs: 'automatic',
-                tags: 'automatic',
-                parentPostIds: 'automatic' },
-            tagSources: {
-                automatic: '',
-                manual: '' },
-            status: 'pending' as const,
-            displayTags: [],
-            resetSnapshot: {
-                url: row.url,
-                attributes: {
-                    title: '',
-                    thumbnailBase: '',
-                    originalCreatedFrom: '',
-                    originalCreatedBefore: '',
-                    duration: '',
-                    videoMs: '',
-                    tags: '',
-                    parentPostIds: '' },
-                provenance: {
-                    url: 'manual',
-                    title: 'automatic',
-                    thumbnailBase: 'automatic',
-                    originalCreatedFrom: 'automatic',
-                    originalCreatedBefore: 'automatic',
-                    duration: 'automatic',
-                    videoMs: 'automatic',
-                    tags: 'automatic',
-                    parentPostIds: 'automatic' },
-                tagSources: {
-                    automatic: '',
-                    manual: '' },
-                displayTags: [],
-                fieldWarnings: { },
-                baseWarnings: [] } }))
-
 
 const PostImportSourcePage: FC<Props> = ({ user }) => {
   const editable = canEditContent (user)
@@ -117,6 +49,8 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
   const editedRef = useRef (false)
 
   const lineCount = countImportSourceLines (source)
+  const sourceUrls = extractImportSourceUrls (source)
+  const withinPathLimit = isPostNewReviewPathWithinLimit (sourceUrls)
   const messages = sourceError != null ? [sourceError] : []
   const sourceDescribedBy =
       [sourceError != null ? SOURCE_ERROR_ID : null,
@@ -124,13 +58,7 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
       .filter (value => value != null)
       .join (' ')
 
-  const showStorageError = (message: string) =>
-      toast ({ description: message })
-
   useEffect (() => {
-    cleanupExpiredPostImportSessions (message =>
-	toast ({ title: '保存済みデータを整理できませんでした', description: message }))
-
     const draft = loadPostImportSourceDraft (message =>
 	toast ({ title: '保存済み入力を復元できませんでした', description: message }))
 
@@ -173,73 +101,15 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 	setSourceError (null)
 	return
       }
+    if (!(withinPathLimit))
+      return
 
     setLoading (true)
     setSourceIssues ([])
     setSourceError (null)
     try
     {
-      const nextRows = initialisePreviewRows (buildInitialRows (source))
+      navigate (buildPostNewReviewPath (sourceUrls))
-      const serialised = await serialisePostNewState (nextRows)
-      const sessionId = (() => {
-	try
-	{
-	  return generatePostImportSessionId ()
-	}
-	catch
-	{
-	  return null
-	}
-      }) ()
-      const session = {
-	  source,
-	  rows: nextRows,
-	  repairMode: resultRepairMode (nextRows) }
-      const saved =
-	  sessionId == null
-	  ? false
-	  : savePostImportSession (sessionId, session, showStorageError)
-      const loadedSession =
-	  sessionId == null
-	  ? null
-	  : loadPostImportSession (sessionId, showStorageError)
-      const sessionRoundTripSucceeded =
-	  saved
-	  && serialisedPostImportRowsEqual (
-	      loadedSession?.rows ?? [],
-	      nextRows)
-      const canNavigate =
-	  serialised?.complete === true
-	  || sessionRoundTripSucceeded
-      if (!(canNavigate))
-	{
-	  showStorageError ('ブラウザへ保存できませんでした．')
-	  return
-	}
-
-      const nextPath = (() => {
-	if (serialised != null)
-	  {
-	    return sessionId == null
-		? serialised.path
-		: appendPostNewSessionId (serialised.path, sessionId)
-	  }
-	if (sessionRoundTripSucceeded && sessionId != null)
-	  return `/posts/new?session_id=${ sessionId }`
-	return null
-      }) ()
-      if (nextPath == null)
-	{
-	  showStorageError ('ブラウザへ保存できませんでした．')
-	  return
-	}
-
-      navigate (nextPath)
-    }
-    catch (error)
-    {
-      console.error (error)
-      showStorageError ('ブラウザへ保存できませんでした．')
     }
     finally
     {
@@ -268,7 +138,8 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 		    className="h-80 font-mono text-sm"
 		    onBlur={() => {
 		      savePostImportSourceDraft (source, message =>
-			  toast ({ title: '入力内容を保存できませんでした',
+			  toast ({
+			      title: '入力内容を保存できませんでした',
 			      description: message }))
 		    }}
 		    onChange={ev => {
@@ -299,7 +170,7 @@ const PostImportSourcePage: FC<Props> = ({ user }) => {
 		type="button"
 		className="pointer-events-auto shrink-0"
 		onClick={preview}
-		disabled={loading}>
+		disabled={loading || !(withinPathLimit)}>
 	      次へ
 	    </Button>
 	  </div>