#306

AGENTS.md

@@ -197,6 +197,16 @@ const value =
 
 - Inspect existing routes, controllers, models, services, and specs before
   editing backend behavior.
+- Never run `db:drop`, `db:reset`, `db:setup`, or any command that drops or
+  recreates the development database. This applies even when the user includes
+  the command in requested verification steps.
+- Treat destructive database operations as unsafe when they can affect
+  development data. Ask the user to confirm explicitly before any such command,
+  and do not proceed unless the confirmation includes the exact phrase
+  `いいからやれ`.
+- Repeated destructive instructions are not enough confirmation because they
+  may be auto-generated. Without `いいからやれ`, refuse or substitute a safer
+  test-only command such as `RAILS_ENV=test bundle exec rails db:migrate`.
 - For API behavior changes, add or update request specs under
   `backend/spec/requests` only when the user explicitly asks for tests.
 - Prefer RSpec for new backend tests; existing minitest files under

backend/app/controllers/materials_controller.rb

@@ -1,4 +1,8 @@
 class MaterialsController < ApplicationController
+  rescue_from MaterialZipExporter::EmptyExportError, with: :render_zip_empty
+  rescue_from MaterialZipExporter::DuplicatePathError, with: :render_zip_duplicate_path
+  rescue_from MaterialZipExporter::MissingFileError, with: :render_zip_missing_file
+
   def index
     page = (params[:page].presence || 1).to_i
     limit = (params[:limit].presence || 20).to_i
@@ -11,7 +15,7 @@ class MaterialsController < ApplicationController
     tag_id = params[:tag_id].presence
     parent_id = params[:parent_id].presence
 
-    q = Material.includes(:tag, :created_by_user).with_attached_file
+    q = Material.includes(:tag, :created_by_user, :material_export_items).with_attached_file
     q = q.where(tag_id:) if tag_id
     q = q.where(parent_id:) if parent_id
 
@@ -24,7 +28,7 @@ class MaterialsController < ApplicationController
   def show
     material =
         Material
-        .includes(:tag)
+        .includes(:tag, :material_export_items)
         .with_attached_file
         .find_by(id: params[:id])
     return head :not_found unless material
@@ -36,26 +40,44 @@ class MaterialsController < ApplicationController
 
   def create
     return head :unauthorized unless current_user
+    return head :forbidden unless current_user.gte_member?
 
     tag_name_raw = params[:tag].to_s.strip
     file = params[:file]
+    file_sha256 = MaterialFileSha256.from_upload(file)
     url = params[:url].to_s.strip.presence
     return render_unprocessable_entity('タグは必須です．', field: :tag) if tag_name_raw.blank?
     if file.blank? && url.blank?
       return render_validation_error fields: { file: ['ファイルまたは URL は必須です．'],
                                                url: ['ファイルまたは URL は必須です．'] }
     end
+    block = MaterialImportBlockMatcher.match_for_sha256(file_sha256)
+    return render_material_import_block(block) if block
 
-    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
-    tag = tag_name.tag
-    tag = Tag.create!(tag_name:, category: :material) unless tag
+    uploaded_blob = build_uploaded_material_blob!(file, file_sha256)
+    material = nil
 
-    material = Material.new(tag:, url:,
-                            created_by_user: current_user,
-                            updated_by_user: current_user)
-    material.file.attach(file)
+    begin
+      Material.transaction do
+        tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
+        tag = tag_name.tag
+        tag = Tag.create!(tag_name:, category: :material) unless tag
 
-    if material.save
+        material = Material.new(tag:, url:,
+                                created_by_user: current_user,
+                                updated_by_user: current_user)
+        material.file.attach(uploaded_blob) if uploaded_blob
+        material.save!
+        upsert_export_paths!(material)
+        MaterialVersionRecorder.record!(material:, event_type: :create,
+                                        created_by_user: current_user)
+      end
+    rescue StandardError
+      uploaded_blob&.purge_later
+      raise
+    end
+
+    if material
       render json: MaterialRepr.base(material, host: request.base_url), status: :created
     else
       render_validation_error material
@@ -71,29 +93,43 @@ class MaterialsController < ApplicationController
 
     tag_name_raw = params[:tag].to_s.strip
     file = params[:file]
-    url = params[:url].to_s.strip.presence
+    file_sha256 = MaterialFileSha256.from_upload(file)
+    url = params.key?(:url) ? params[:url].to_s.strip.presence : material.url
     return render_unprocessable_entity('タグは必須です．', field: :tag) if tag_name_raw.blank?
-    if file.blank? && url.blank?
+    if file.blank? && url.blank? && !material.file.attached?
       return render_validation_error fields: { file: ['ファイルまたは URL は必須です．'],
                                                url: ['ファイルまたは URL は必須です．'] }
     end
+    block = MaterialImportBlockMatcher.match_for_sha256(file_sha256)
+    return render_material_import_block(block) if block
 
-    tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
-    tag = tag_name.tag
-    tag = Tag.create!(tag_name:, category: :material) unless tag
+    uploaded_blob = build_uploaded_material_blob!(file, file_sha256)
 
-    material.update!(tag:, url:, updated_by_user: current_user)
-    if file
-      material.file.attach(file)
-    else
-      material.file.purge
+    begin
+      Material.transaction do
+        MaterialVersionRecorder.ensure_snapshot!(material, created_by_user: current_user)
+        tag_name = TagName.find_undiscard_or_create_by!(name: tag_name_raw)
+        tag = tag_name.tag
+        tag = Tag.create!(tag_name:, category: :material) unless tag
+
+        material.assign_attributes(tag:, url:, updated_by_user: current_user)
+        if uploaded_blob
+          material.file.attach(uploaded_blob)
+          clear_file_suppression!(material)
+        elsif params.key?(:url) && url.present? && file.blank?
+          material.file.detach
+        end
+        material.save!
+        upsert_export_paths!(material)
+        MaterialVersionRecorder.record!(material:, event_type: :update,
+                                        created_by_user: current_user)
+      end
+    rescue StandardError
+      uploaded_blob&.purge_later
+      raise
     end
 
-    if material.save
-      render json: MaterialRepr.base(material, host: request.base_url)
-    else
-      render_validation_error material
-    end
+    render json: MaterialRepr.base(material, host: request.base_url)
   end
 
   def destroy
@@ -103,7 +139,146 @@ class MaterialsController < ApplicationController
     material = Material.find_by(id: params[:id])
     return head :not_found unless material
 
-    material.discard
+    Material.transaction do
+      MaterialVersionRecorder.ensure_snapshot!(material, created_by_user: current_user)
+      material.discard!
+      MaterialVersionRecorder.record!(material:, event_type: :discard,
+                                      created_by_user: current_user)
+    end
     head :no_content
   end
+
+  def download
+    zip = MaterialZipExporter.new(profile: params[:profile],
+                                  tag_id: params[:tag_id]).export
+    profile = params[:profile].presence || 'legacy_drive'
+    send_data zip,
+              type: 'application/zip',
+              disposition: 'attachment',
+              filename: "btrc-materials-#{ profile }.zip"
+  end
+
+  def suppress_file
+    return head :unauthorized unless current_user
+    return head :forbidden unless current_user.admin?
+
+    material = Material.with_attached_file.find_by(id: params[:id])
+    return head :not_found unless material
+
+    reason = params[:reason].to_s.strip.presence
+    return render_unprocessable_entity('理由は必須です．', field: :reason) unless reason
+    purge = bool?(:purge)
+    file_snapshot = purge_material_file_snapshot(material) if purge
+    attachment = purge && material.file.attached? ? material.file.attachment : nil
+
+    Material.transaction do
+      MaterialVersionRecorder.ensure_snapshot!(material, created_by_user: current_user)
+      material.update!(file_suppressed_at: Time.current,
+                       file_suppressed_by_user: current_user,
+                       file_suppression_reason: reason,
+                       updated_by_user: current_user)
+      MaterialVersionRecorder.record!(material:, event_type: :suppress,
+                                      created_by_user: current_user,
+                                      file_snapshot:)
+    end
+    # Enqueue failure raises here after the suppress metadata has been committed.
+    # In that case the file remains suppressed in UI/ZIP and purge can be retried.
+    attachment&.purge_later
+    material.reload if purge
+
+    render json: MaterialRepr.base(material, host: request.base_url)
+  end
+
+  private
+
+  def upsert_export_paths! material
+    raw = params[:export_paths]
+    return if raw.blank?
+
+    export_paths = raw.respond_to?(:to_unsafe_h) ? raw.to_unsafe_h : raw.to_h
+    export_paths.each do |profile, export_path|
+      profile = profile.to_s
+      export_path = export_path.to_s.strip
+      item = material.material_export_items.find_or_initialize_by(profile:)
+
+      if export_path.blank?
+        item.destroy! if item.persisted?
+        next
+      end
+
+      item.export_path = export_path
+      item.enabled = true
+      item.created_by_user ||= current_user
+      item.save!
+    end
+  end
+
+  def render_zip_empty
+    render_unprocessable_entity('ZIP export 対象の素材がありません．')
+  end
+
+  def render_zip_duplicate_path error
+    render_unprocessable_entity("ZIP export path が重複してゐます: #{ error.message }")
+  end
+
+  def render_zip_missing_file error
+    missing_files = error.missing_files.map do |missing_file|
+      { material_id: missing_file.material_id,
+        export_path: missing_file.export_path,
+        blob_id: missing_file.blob_id,
+        filename: missing_file.filename }
+    end
+
+    render json: { type: 'validation_error',
+                   message: 'ZIP export に必要な素材ファイルが欠損しています．',
+                   errors: { },
+                   base_errors: ['ZIP export に必要な素材ファイルが欠損しています．'],
+                   missing_files: },
+           status: :unprocessable_entity
+  end
+
+  def build_uploaded_material_blob! file, file_sha256
+    return nil unless file
+
+    file.tempfile.rewind
+
+    blob = ActiveStorage::Blob.create_and_upload!(
+        io: file.tempfile,
+        filename: file.original_filename,
+        content_type: file.content_type,
+    )
+
+    if file_sha256.present?
+      blob.metadata['sha256'] = file_sha256
+      blob.save! if blob.changed?
+    end
+
+    blob
+  ensure
+    file.tempfile.rewind if file&.tempfile
+  end
+
+  def clear_file_suppression! material
+    material.file_suppressed_at = nil
+    material.file_suppressed_by_user = nil
+    material.file_suppression_reason = nil
+  end
+
+  def purge_material_file_snapshot material
+    return nil unless material.file.attached?
+
+    blob = material.file.blob
+
+    { file_blob_id: blob.id,
+      file_filename: blob.filename.to_s,
+      file_content_type: blob.content_type,
+      file_byte_size: blob.byte_size,
+      file_checksum: blob.checksum,
+      file_sha256: blob.metadata['sha256'] ||
+                   MaterialFileSha256.from_blob(blob, allow_download: true) }
+  end
+
+  def render_material_import_block block
+    render_validation_error fields: { file: ["抑止された素材です: #{ block.reason }"] }
+  end
 end

backend/app/controllers/tags_controller.rb

@@ -437,16 +437,10 @@ class TagsController < ApplicationController
 
   def build_tag_children tag
     material = tag.materials.first
-    file = nil
-    content_type = nil
-    if material&.file&.attached?
-      file = rails_storage_proxy_url(material.file, only_path: false)
-      content_type = material.file.blob.content_type
-    end
 
     TagRepr.base(tag).merge(
         children: tag.children.sort_by { _1.name }.map { build_tag_children(_1) },
-        material: material.as_json&.merge(file:, content_type:))
+        material: material && MaterialRepr.base(material, host: request.base_url))
   end
 
   def record_tag_version! tag, event_type:, created_by_user:, name_changed: false, wiki_page: nil

backend/app/models/material.rb

@@ -9,6 +9,10 @@ class Material < ApplicationRecord
   belongs_to :tag, optional: true
   belongs_to :created_by_user, class_name: 'User', optional: true
   belongs_to :updated_by_user, class_name: 'User', optional: true
+  belongs_to :file_suppressed_by_user, class_name: 'User', optional: true
+
+  has_many :material_versions, dependent: :destroy
+  has_many :material_export_items, dependent: :destroy
 
   has_one_attached :file, dependent: :purge
 
@@ -18,11 +22,18 @@ class Material < ApplicationRecord
   validate :tag_must_be_material_category
 
   def content_type
+    return nil if file_suppressed?
     return nil unless file&.attached?
 
     file.blob.content_type
   end
 
+  def file_suppressed? = file_suppressed_at.present?
+
+  def snapshot_export_paths
+    material_export_items.order(:profile).pluck(:profile, :export_path).to_h
+  end
+
   private
 
   def file_must_be_attached

backend/app/models/material_export_item.rb

@@ -0,0 +1,48 @@
+class MaterialExportItem < ApplicationRecord
+  VALID_PROFILES = ['legacy_drive'].freeze
+
+  belongs_to :material
+  belongs_to :created_by_user, class_name: 'User', optional: true
+
+  validates :profile, presence: true, inclusion: { in: VALID_PROFILES }
+  validates :export_path, presence: true, uniqueness: { scope: :profile }
+  validates :material_id, uniqueness: { scope: :profile }
+  validate :export_path_must_be_relative_safe_path
+
+  scope :enabled, -> { where(enabled: true) }
+
+  private
+
+  def export_path_must_be_relative_safe_path
+    return if export_path.blank?
+
+    if export_path.start_with?('/')
+      errors.add(:export_path, '絶対パスは使へません．')
+    end
+
+    if export_path.match?(/\A[A-Za-z]:\//)
+      errors.add(:export_path, '絶対パスは使へません．')
+    end
+
+    if export_path.include?('\\')
+      errors.add(:export_path, '/ 区切りで指定してください．')
+    end
+
+    if export_path.include?("\0")
+      errors.add(:export_path, 'NUL は使へません．')
+    end
+
+    parts = export_path.split('/')
+    if export_path.include?('//')
+      errors.add(:export_path, '空の path segment は使へません．')
+    end
+
+    if parts.any? { |part| part.in?(['.', '..']) }
+      errors.add(:export_path, '.. は使へません．')
+    end
+
+    if export_path.end_with?('/')
+      errors.add(:export_path, 'directory path は使へません．')
+    end
+  end
+end

backend/app/models/material_import_block.rb

@@ -0,0 +1,29 @@
+class MaterialImportBlock < ApplicationRecord
+  MATCH_KINDS = ['sha256', 'exact_path', 'path_prefix', 'manual'].freeze
+  REASONS = [
+    'copyright_high_risk',
+    'copyright_takedown',
+    'adult_or_sensitive',
+    'personal_information',
+    'malware_or_dangerous_file',
+    'duplicate_or_low_quality',
+    'source_owner_request',
+    'other'
+  ].freeze
+
+  belongs_to :created_by_user, class_name: 'User', optional: true
+
+  validates :match_kind, presence: true, inclusion: { in: MATCH_KINDS }
+  validates :reason, presence: true, inclusion: { in: REASONS }
+  validates :sha256, length: { is: 64 }, allow_blank: true
+  validate :match_value_must_be_present
+
+  private
+
+  def match_value_must_be_present
+    return if match_kind == 'manual'
+    return if sha256.present? || external_path_pattern.present?
+
+    errors.add(:base, 'sha256 または external_path_pattern は必須です．')
+  end
+end

backend/app/models/material_version.rb

@@ -0,0 +1,18 @@
+class MaterialVersion < ApplicationRecord
+  EVENT_TYPE_MAP = { create: 'create',
+                     update: 'update',
+                     discard: 'discard',
+                     restore: 'restore',
+                     suppress: 'suppress' }.freeze
+
+  include VersionRecord
+
+  belongs_to :material
+  belongs_to :tag, optional: true
+  belongs_to :parent, class_name: 'Material', optional: true
+  belongs_to :updated_by_user, class_name: 'User', optional: true
+
+  def export_paths_hash
+    export_paths_json || {}
+  end
+end

backend/app/models/version_record.rb

@@ -1,15 +1,23 @@
 module VersionRecord
   extend ActiveSupport::Concern
 
+  DEFAULT_EVENT_TYPE_MAP = { create: 'create',
+                             update: 'update',
+                             discard: 'discard',
+                             restore: 'restore' }.freeze
+
   def readonly? = persisted?
 
   included do
+    event_type_map = if const_defined?(:EVENT_TYPE_MAP, false)
+                       const_get(:EVENT_TYPE_MAP)
+                     else
+                       DEFAULT_EVENT_TYPE_MAP
+                     end
+
     belongs_to :created_by_user, class_name: 'User', optional: true
 
-    enum :event_type, { create: 'create',
-                        update: 'update',
-                        discard: 'discard',
-                        restore: 'restore' }, prefix: true, validate: true
+    enum :event_type, event_type_map, prefix: true, validate: true
 
     validates :version_no, presence: true, numericality: { only_integer: true, greater_than: 0 }
     validates :event_type, presence: true

backend/app/representations/material_repr.rb

@@ -2,7 +2,8 @@
 
 
 module MaterialRepr
-  BASE = { only: [:id, :url, :created_at, :updated_at],
+  BASE = { only: [:id, :url, :version_no, :file_suppressed_at,
+                  :file_suppression_reason, :created_at, :updated_at],
            methods: [:content_type],
            include: { tag: TagRepr::BASE,
                       created_by_user: UserRepr::BASE,
@@ -12,13 +13,30 @@ module MaterialRepr
 
   def base material, host:
     material.as_json(BASE).merge(
-        file: if material.file.attached?
+        file: if material.file.attached? && !material.file_suppressed?
                 Rails.application.routes.url_helpers.rails_storage_proxy_url(
                     material.file, host:)
-              end)
+              end,
+        export_paths: export_paths(material),
+        export_items: export_items(material))
   end
 
   def many materials, host:
     materials.map { |m| base(m, host:) }
   end
+
+  def export_paths material
+    material.material_export_items.each_with_object({ }) do |item, hash|
+      hash[item.profile] = item.enabled ? item.export_path : ''
+    end
+  end
+
+  def export_items material
+    material.material_export_items.map do |item|
+      { id: item.id,
+        profile: item.profile,
+        export_path: item.export_path,
+        enabled: item.enabled }
+    end
+  end
 end

backend/app/services/material_file_sha256.rb

@@ -0,0 +1,34 @@
+require 'digest'
+
+class MaterialFileSha256
+  def self.from_blob blob, allow_download: false
+    sha256 = blob.metadata['sha256']
+    return sha256 if sha256.present?
+    return nil unless allow_download
+
+    begin
+      blob.open do |file|
+        sha256 = Digest::SHA256.file(file.path).hexdigest
+        blob.metadata['sha256'] = sha256
+        blob.save! if blob.changed?
+        sha256
+      end
+    rescue ActiveStorage::FileNotFoundError, ArgumentError => error
+      Rails.logger.warn(
+          "MaterialFileSha256.from_blob failed for blob_id=#{blob.id}: " \
+          "#{error.class}: #{error.message}",
+      )
+      nil
+    end
+  end
+
+  def self.from_upload upload
+    tempfile = upload&.tempfile
+    return nil unless tempfile
+
+    tempfile.rewind
+    Digest::SHA256.file(tempfile.path).hexdigest.tap do
+      tempfile.rewind
+    end
+  end
+end

backend/app/services/material_import_block_matcher.rb

@@ -0,0 +1,7 @@
+class MaterialImportBlockMatcher
+  def self.match_for_sha256 sha256
+    return nil if sha256.blank?
+
+    MaterialImportBlock.find_by(match_kind: 'sha256', sha256:)
+  end
+end

backend/app/services/material_version_recorder.rb

@@ -0,0 +1,70 @@
+class MaterialVersionRecorder < VersionRecorder
+  EVENT_TYPES = ['create', 'update', 'discard', 'restore', 'suppress'].freeze
+
+  def self.record! material:, event_type:, created_by_user:, file_snapshot: nil
+    new(material:, event_type:, created_by_user:, file_snapshot:).record!
+  end
+
+  def initialize material:, event_type:, created_by_user:, file_snapshot: nil
+    @file_snapshot = file_snapshot
+
+    super(record: material, event_type:, created_by_user:)
+  end
+
+  def self.ensure_snapshot! material, created_by_user:
+    return if material.material_versions.exists?
+
+    record!(material:, event_type: :create,
+            created_by_user: material.created_by_user || created_by_user)
+  end
+
+  private
+
+  def version_class = MaterialVersion
+  def version_association = :material_versions
+  def record_key = :material
+
+  def snapshot_attributes
+    blob = @record.file.attached? ? @record.file.blob : nil
+    file_snapshot = build_file_snapshot(blob)
+
+    { url: @record.url,
+      parent: @record.parent,
+      tag: @record.tag,
+      tag_name: @record.tag&.name,
+      tag_category: @record.tag&.category,
+      export_paths_json: @record.snapshot_export_paths,
+      discarded_at: @record.discarded_at,
+      file_blob_id: file_snapshot[:file_blob_id],
+      file_filename: file_snapshot[:file_filename],
+      file_content_type: file_snapshot[:file_content_type],
+      file_byte_size: file_snapshot[:file_byte_size],
+      file_checksum: file_snapshot[:file_checksum],
+      file_sha256: file_snapshot[:file_sha256],
+      file_suppressed_at: @record.file_suppressed_at,
+      file_suppression_reason: @record.file_suppression_reason }
+  end
+
+  def build_file_snapshot blob
+    return @file_snapshot if @file_snapshot
+    return empty_file_snapshot unless blob
+
+    { file_blob_id: blob.id,
+      file_filename: blob.filename.to_s,
+      file_content_type: blob.content_type,
+      file_byte_size: blob.byte_size,
+      file_checksum: blob.checksum,
+      file_sha256: blob.metadata['sha256'] }
+  end
+
+  def empty_file_snapshot
+    { file_blob_id: nil,
+      file_filename: nil,
+      file_content_type: nil,
+      file_byte_size: nil,
+      file_checksum: nil,
+      file_sha256: nil }
+  end
+
+  def event_types = self.class::EVENT_TYPES
+end

backend/app/services/material_zip_exporter.rb

@@ -0,0 +1,149 @@
+require 'stringio'
+require 'zlib'
+
+# Initial implementation keeps every file payload and the final ZIP in memory.
+# Keep this service boundary stable so job/cached export paths can replace it later.
+class MaterialZipExporter
+  Entry = Struct.new(:path, :data, :mtime, keyword_init: true)
+  MissingFile = Struct.new(:material_id, :export_path, :blob_id, :filename, keyword_init: true)
+
+  class EmptyExportError < StandardError; end
+  class DuplicatePathError < StandardError; end
+  class MissingFileError < StandardError
+    attr_reader :missing_files
+
+    def initialize missing_files
+      @missing_files = missing_files
+
+      super("Missing files: #{missing_files.map(&:export_path).join(', ')}")
+    end
+  end
+
+  def initialize profile: 'legacy_drive', tag_id: nil
+    @profile = profile.presence || 'legacy_drive'
+    @tag_id = tag_id.presence
+  end
+
+  def export
+    entries = build_entries
+    raise EmptyExportError if entries.empty?
+
+    ZipWriter.write(entries)
+  end
+
+  private
+
+  def build_entries
+    rows = MaterialExportItem
+           .enabled
+           .includes(material: { file_attachment: :blob })
+           .joins(:material)
+           .merge(Material.kept)
+           .where(profile: @profile)
+           .where(materials: { file_suppressed_at: nil })
+           .order(:export_path)
+
+    rows = rows.where(materials: { tag_id: @tag_id }) if @tag_id
+
+    missing_files = []
+
+    entries = rows.filter_map do |item|
+      material = item.material
+      next unless material.file.attached?
+
+      data = download_blob(item, missing_files)
+      next unless data
+
+      Entry.new(path: item.export_path,
+                data:,
+                mtime: material.updated_at || Time.current)
+    end
+
+    raise MissingFileError.new(missing_files) if missing_files.any?
+
+    paths = entries.map(&:path)
+    duplicated = paths.find { |path| paths.count(path) > 1 }
+    raise DuplicatePathError, duplicated if duplicated
+
+    entries
+  end
+
+  def download_blob item, missing_files
+    blob = item.material.file.blob
+
+    blob.download
+  rescue ActiveStorage::FileNotFoundError
+    missing_files << MissingFile.new(
+        material_id: item.material_id,
+        export_path: item.export_path,
+        blob_id: blob.id,
+        filename: blob.filename.to_s,
+    )
+    nil
+  end
+
+  class ZipWriter
+    VERSION_NEEDED = 20
+    GP_FLAG = 0x0800
+    COMPRESSION_STORE = 0
+
+    def self.write entries
+      new(entries).write
+    end
+
+    def initialize entries
+      @entries = entries
+      @central_directory = []
+    end
+
+    def write
+      io = StringIO.new(''.b)
+
+      @entries.each do |entry|
+        write_entry(io, entry)
+      end
+
+      central_start = io.pos
+      @central_directory.each { |header| io.write(header) }
+      central_size = io.pos - central_start
+
+      io.write([0x06054b50, 0, 0, @entries.size, @entries.size,
+                central_size, central_start, 0].pack('VvvvvVVv'))
+      io.string
+    end
+
+    private
+
+    def write_entry io, entry
+      path = entry.path.b
+      data = entry.data.b
+      crc32 = Zlib.crc32(data)
+      dos_time, dos_date = dos_timestamp(entry.mtime)
+      offset = io.pos
+
+      local_header = [0x04034b50, VERSION_NEEDED, GP_FLAG, COMPRESSION_STORE,
+                      dos_time, dos_date, crc32, data.bytesize, data.bytesize,
+                      path.bytesize, 0].pack('VvvvvvVVVvv')
+
+      io.write(local_header)
+      io.write(path)
+      io.write(data)
+
+      @central_directory << central_header(path:, crc32:, size: data.bytesize,
+                                           dos_time:, dos_date:, offset:)
+    end
+
+    def central_header path:, crc32:, size:, dos_time:, dos_date:, offset:
+      [0x02014b50, VERSION_NEEDED, VERSION_NEEDED, GP_FLAG, COMPRESSION_STORE,
+       dos_time, dos_date, crc32, size, size, path.bytesize, 0, 0, 0, 0, 0,
+       offset].pack('VvvvvvvVVVvvvvvVV') + path
+    end
+
+    def dos_timestamp time
+      local = time.to_time
+      dos_time = (local.hour << 11) | (local.min << 5) | (local.sec / 2)
+      dos_date = ((local.year - 1980) << 9) | (local.month << 5) | local.day
+      [dos_time, dos_date]
+    end
+  end
+end

backend/app/services/version_recorder.rb

@@ -73,7 +73,7 @@ class VersionRecorder
   end
 
   def validate_event_type!
-    return if EVENT_TYPES.include?(@event_type)
+    return if event_types.include?(@event_type)
 
     raise ArgumentError, "Invalid event_type: #{ @event_type }"
   end
@@ -84,4 +84,5 @@ class VersionRecorder
   def snapshot_attributes = raise NotImplementedError
 
   def record_class = @record.class
+  def event_types = self.class::EVENT_TYPES
 end

backend/config/routes.rb

@@ -113,5 +113,10 @@ Rails.application.routes.draw do
     resources :skip_events, controller: :theatre_skip_events, only: [:index]
   end
 
-  resources :materials, only: [:index, :show, :create, :update, :destroy]
+  get 'materials/download.zip', to: 'materials#download'
+  resources :materials, only: [:index, :show, :create, :update, :destroy] do
+    member do
+      patch :suppress_file
+    end
+  end
 end

backend/db/migrate/20260623000000_enhance_material_management.rb

@@ -0,0 +1,98 @@
+class EnhanceMaterialManagement < ActiveRecord::Migration[8.0]
+  def up
+    change_table :materials, bulk: true do |t|
+      t.integer :version_no, null: false, default: 1
+      t.datetime :file_suppressed_at
+      t.references :file_suppressed_by_user, foreign_key: { to_table: :users }
+      t.string :file_suppression_reason
+    end
+
+    change_table :material_versions, bulk: true do |t|
+      t.string :event_type
+      t.string :tag_name
+      t.string :tag_category
+      t.json :export_paths_json
+      t.bigint :file_blob_id
+      t.string :file_filename
+      t.string :file_content_type
+      t.bigint :file_byte_size
+      t.string :file_checksum
+      t.string :file_sha256
+      t.datetime :file_suppressed_at
+      t.string :file_suppression_reason
+    end
+
+    execute <<~SQL.squish
+      UPDATE material_versions
+      SET event_type = CASE
+                       WHEN version_no = 1 THEN 'create'
+                       ELSE 'update'
+                       END
+      WHERE event_type IS NULL
+    SQL
+
+    change_column_null :material_versions, :event_type, false
+    add_index :material_versions, :file_blob_id
+
+    add_check_constraint :material_versions,
+                         "event_type IN ('create', 'update', 'discard', 'restore', 'suppress')",
+                         name: 'material_versions_event_type_valid'
+
+    create_table :material_export_items do |t|
+      t.references :material, null: false, foreign_key: true
+      t.string :profile, null: false, default: 'legacy_drive'
+      t.string :export_path, null: false
+      t.boolean :enabled, null: false, default: true
+      t.references :created_by_user, foreign_key: { to_table: :users }
+      t.timestamps
+
+      t.index [:profile, :export_path], unique: true
+      t.index [:material_id, :profile], unique: true
+    end
+
+    create_table :material_import_blocks do |t|
+      t.string :match_kind, null: false
+      t.string :sha256
+      t.string :external_path_pattern
+      t.string :reason, null: false
+      t.text :note
+      t.references :created_by_user, foreign_key: { to_table: :users }
+      t.timestamps
+    end
+
+    execute <<~SQL.squish
+      UPDATE materials
+      SET version_no = COALESCE(
+        (SELECT MAX(material_versions.version_no)
+         FROM material_versions
+         WHERE material_versions.material_id = materials.id),
+        1)
+    SQL
+  end
+
+  def down
+    drop_table :material_import_blocks
+    drop_table :material_export_items
+
+    remove_check_constraint :material_versions, name: 'material_versions_event_type_valid'
+
+    remove_index :material_versions, :file_blob_id
+    remove_column :material_versions, :event_type
+    remove_column :material_versions, :tag_name
+    remove_column :material_versions, :tag_category
+    remove_column :material_versions, :export_paths_json
+    remove_column :material_versions, :file_blob_id
+    remove_column :material_versions, :file_filename
+    remove_column :material_versions, :file_content_type
+    remove_column :material_versions, :file_byte_size
+    remove_column :material_versions, :file_checksum
+    remove_column :material_versions, :file_sha256
+    remove_column :material_versions, :file_suppressed_at
+    remove_column :material_versions, :file_suppression_reason
+
+    remove_reference :materials, :file_suppressed_by_user, foreign_key: { to_table: :users }
+    remove_column :materials, :version_no
+    remove_column :materials, :file_suppressed_at
+    remove_column :materials, :file_suppression_reason
+  end
+end

backend/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_06_21_000000) do
+ActiveRecord::Schema[8.0].define(version: 2026_06_23_000000) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -130,6 +130,32 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_21_000000) do
     t.index ["ip_address"], name: "index_ip_addresses_on_ip_address", unique: true
   end
 
+  create_table "material_export_items", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "material_id", null: false
+    t.string "profile", default: "legacy_drive", null: false
+    t.string "export_path", null: false
+    t.boolean "enabled", default: true, null: false
+    t.bigint "created_by_user_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["created_by_user_id"], name: "index_material_export_items_on_created_by_user_id"
+    t.index ["material_id", "profile"], name: "index_material_export_items_on_material_id_and_profile", unique: true
+    t.index ["material_id"], name: "index_material_export_items_on_material_id"
+    t.index ["profile", "export_path"], name: "index_material_export_items_on_profile_and_export_path", unique: true
+  end
+
+  create_table "material_import_blocks", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.string "match_kind", null: false
+    t.string "sha256"
+    t.string "external_path_pattern"
+    t.string "reason", null: false
+    t.text "note"
+    t.bigint "created_by_user_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["created_by_user_id"], name: "index_material_import_blocks_on_created_by_user_id"
+  end
+
   create_table "material_versions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "material_id", null: false
     t.integer "version_no", null: false
@@ -141,14 +167,28 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_21_000000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.datetime "discarded_at"
+    t.string "event_type", null: false
+    t.string "tag_name"
+    t.string "tag_category"
+    t.json "export_paths_json"
+    t.bigint "file_blob_id"
+    t.string "file_filename"
+    t.string "file_content_type"
+    t.bigint "file_byte_size"
+    t.string "file_checksum"
+    t.string "file_sha256"
+    t.datetime "file_suppressed_at"
+    t.string "file_suppression_reason"
     t.index ["created_by_user_id"], name: "index_material_versions_on_created_by_user_id"
     t.index ["discarded_at"], name: "index_material_versions_on_discarded_at"
+    t.index ["file_blob_id"], name: "index_material_versions_on_file_blob_id"
     t.index ["material_id", "version_no"], name: "index_material_versions_on_material_id_and_version_no", unique: true
     t.index ["material_id"], name: "index_material_versions_on_material_id"
     t.index ["parent_id"], name: "index_material_versions_on_parent_id"
     t.index ["tag_id"], name: "index_material_versions_on_tag_id"
     t.index ["updated_by_user_id"], name: "index_material_versions_on_updated_by_user_id"
     t.index ["url"], name: "index_material_versions_on_url"
+    t.check_constraint "`event_type` in (_utf8mb4'create',_utf8mb4'update',_utf8mb4'discard',_utf8mb4'restore',_utf8mb4'suppress')", name: "material_versions_event_type_valid"
   end
 
   create_table "materials", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
@@ -161,9 +201,14 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_21_000000) do
     t.datetime "updated_at", null: false
     t.datetime "discarded_at"
     t.virtual "active_url", type: :string, as: "if((`discarded_at` is null),`url`,NULL)"
+    t.integer "version_no", default: 1, null: false
+    t.datetime "file_suppressed_at"
+    t.bigint "file_suppressed_by_user_id"
+    t.string "file_suppression_reason"
     t.index ["active_url"], name: "index_materials_on_active_url", unique: true
     t.index ["created_by_user_id"], name: "index_materials_on_created_by_user_id"
     t.index ["discarded_at"], name: "index_materials_on_discarded_at"
+    t.index ["file_suppressed_by_user_id"], name: "index_materials_on_file_suppressed_by_user_id"
     t.index ["parent_id"], name: "index_materials_on_parent_id"
     t.index ["tag_id"], name: "index_materials_on_tag_id"
     t.index ["updated_by_user_id"], name: "index_materials_on_updated_by_user_id"
@@ -567,6 +612,9 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_21_000000) do
   add_foreign_key "gekanator_question_suggestions", "users"
   add_foreign_key "gekanator_questions", "gekanator_question_suggestions"
   add_foreign_key "gekanator_questions", "users", column: "created_by_id"
+  add_foreign_key "material_export_items", "materials"
+  add_foreign_key "material_export_items", "users", column: "created_by_user_id"
+  add_foreign_key "material_import_blocks", "users", column: "created_by_user_id"
   add_foreign_key "material_versions", "materials"
   add_foreign_key "material_versions", "materials", column: "parent_id"
   add_foreign_key "material_versions", "tags"
@@ -575,6 +623,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_06_21_000000) do
   add_foreign_key "materials", "materials", column: "parent_id"
   add_foreign_key "materials", "tags"
   add_foreign_key "materials", "users", column: "created_by_user_id"
+  add_foreign_key "materials", "users", column: "file_suppressed_by_user_id"
   add_foreign_key "materials", "users", column: "updated_by_user_id"
   add_foreign_key "nico_tag_relations", "tags"
   add_foreign_key "nico_tag_relations", "tags", column: "nico_tag_id"

backend/spec/models/material_export_item_spec.rb

@@ -0,0 +1,57 @@
+require 'rails_helper'
+
+RSpec.describe MaterialExportItem, type: :model do
+  let(:user) { create(:user, :member) }
+  let(:tag) { Tag.create!(tag_name: TagName.create!(name: 'export_item'), category: :material) }
+  let(:material) do
+    Material.create!(tag:, url: 'https://example.com/material',
+                     created_by_user: user, updated_by_user: user)
+  end
+
+  it 'rejects blank export_path' do
+    item = described_class.new(material:, profile: 'legacy_drive', export_path: '')
+
+    expect(item).not_to be_valid
+    expect(item.errors[:export_path]).to be_present
+  end
+
+  it 'rejects absolute export_path' do
+    item = described_class.new(material:, profile: 'legacy_drive',
+                               export_path: '/素材/a.png')
+
+    expect(item).not_to be_valid
+    expect(item.errors[:export_path]).to be_present
+  end
+
+  it 'rejects parent traversal export_path' do
+    item = described_class.new(material:, profile: 'legacy_drive',
+                               export_path: '素材/../a.png')
+
+    expect(item).not_to be_valid
+    expect(item.errors[:export_path]).to be_present
+  end
+
+  it 'rejects double slash export_path' do
+    item = described_class.new(material:, profile: 'legacy_drive',
+                               export_path: '素材//a.png')
+
+    expect(item).not_to be_valid
+    expect(item.errors[:export_path]).to be_present
+  end
+
+  it 'rejects dot segment export_path' do
+    item = described_class.new(material:, profile: 'legacy_drive',
+                               export_path: './素材/a.png')
+
+    expect(item).not_to be_valid
+    expect(item.errors[:export_path]).to be_present
+  end
+
+  it 'rejects trailing slash export_path' do
+    item = described_class.new(material:, profile: 'legacy_drive',
+                               export_path: '素材/a/')
+
+    expect(item).not_to be_valid
+    expect(item.errors[:export_path]).to be_present
+  end
+end

backend/spec/requests/materials_spec.rb

@@ -1,7 +1,10 @@
 require 'rails_helper'
 
 RSpec.describe 'Materials API', type: :request do
+  include ActiveJob::TestHelper
+
   let!(:member_user) { create(:user, :member) }
+  let!(:admin_user)  { create(:user, :admin) }
   let!(:guest_user)  { create(:user) }
 
   def dummy_upload(filename: 'dummy.png', type: 'image/png', body: 'dummy')
@@ -13,22 +16,29 @@ RSpec.describe 'Materials API', type: :request do
   end
 
   def build_material(tag:, user:, parent: nil, file: dummy_upload, url: nil)
-    Material.new(tag:, parent:, url:, created_by_user: user, updated_by_user: user).tap do |material|
+    Material.new(tag:, parent:, url:,
+                 created_by_user: user,
+                 updated_by_user: user).tap do |material|
       material.file.attach(file) if file
       material.save!
     end
   end
 
   describe 'GET /materials' do
-    let!(:tag_a) { Tag.create!(tag_name: TagName.create!(name: 'material_index_a'), category: :material) }
-    let!(:tag_b) { Tag.create!(tag_name: TagName.create!(name: 'material_index_b'), category: :material) }
+    let!(:tag_a) do
+      Tag.create!(tag_name: TagName.create!(name: 'material_index_a'), category: :material)
+    end
+    let!(:tag_b) do
+      Tag.create!(tag_name: TagName.create!(name: 'material_index_b'), category: :material)
+    end
 
     let!(:material_a) do
       build_material(tag: tag_a, user: member_user, file: dummy_upload(filename: 'a.png'))
     end
 
     let!(:material_b) do
-      build_material(tag: tag_b, user: member_user, parent: material_a, file: dummy_upload(filename: 'b.png'))
+      build_material(tag: tag_b, user: member_user, parent: material_a,
+                     file: dummy_upload(filename: 'b.png'))
     end
 
     before do
@@ -97,7 +107,9 @@ RSpec.describe 'Materials API', type: :request do
   end
 
   describe 'GET /materials/:id' do
-    let!(:tag) { Tag.create!(tag_name: TagName.create!(name: 'material_show'), category: :material) }
+    let!(:tag) do
+      Tag.create!(tag_name: TagName.create!(name: 'material_show'), category: :material)
+    end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'show.png'))
     end
@@ -138,9 +150,22 @@ RSpec.describe 'Materials API', type: :request do
       end
     end
 
-    context 'when logged in' do
+    context 'when logged in but not member' do
       before { sign_in_as(guest_user) }
 
+      it 'returns 403' do
+        post '/materials', params: {
+          tag: 'material_create_guest_forbidden',
+          file: dummy_upload
+        }
+
+        expect(response).to have_http_status(:forbidden)
+      end
+    end
+
+    context 'when member' do
+      before { sign_in_as(member_user) }
+
       it 'returns 422 when tag is blank' do
         post '/materials', params: { tag: '   ', file: dummy_upload }
 
@@ -162,24 +187,49 @@ RSpec.describe 'Materials API', type: :request do
         expect do
           post '/materials', params: {
             tag: 'material_create_new',
-            file: dummy_upload(filename: 'created.png')
+            file: dummy_upload(filename: 'created.png'),
+            export_paths: { legacy_drive: '伊地知ニジカ/created.png' }
           }
         end.to change(Material, :count).by(1)
           .and change(Tag, :count).by(1)
           .and change(TagName, :count).by(1)
+          .and change(MaterialVersion, :count).by(1)
 
         expect(response).to have_http_status(:created)
 
         material = Material.order(:id).last
         expect(material.tag.name).to eq('material_create_new')
         expect(material.tag.category).to eq('material')
-        expect(material.created_by_user).to eq(guest_user)
-        expect(material.updated_by_user).to eq(guest_user)
+        expect(material.created_by_user).to eq(member_user)
+        expect(material.updated_by_user).to eq(member_user)
         expect(material.file.attached?).to be(true)
+        expect(material.version_no).to eq(1)
+        expect(material.material_versions.first.event_type).to eq('create')
+        expect(material.material_export_items.first.export_path).to eq('伊地知ニジカ/created.png')
+        expect(material.material_versions.first.export_paths_json).to eq(
+          'legacy_drive' => '伊地知ニジカ/created.png'
+        )
 
         expect(json['id']).to eq(material.id)
         expect(json.dig('tag', 'name')).to eq('material_create_new')
         expect(json['content_type']).to eq('image/png')
+        expect(json.dig('export_paths', 'legacy_drive')).to eq('伊地知ニジカ/created.png')
+      end
+
+      it 'snapshots attached file metadata and sha256' do
+        post '/materials', params: {
+          tag: 'material_create_file_version',
+          file: dummy_upload(filename: 'created.png', body: 'sha-body')
+        }
+
+        expect(response).to have_http_status(:created)
+
+        version = Material.order(:id).last.material_versions.first
+        expect(version.file_blob_id).to be_present
+        expect(version.file_filename).to eq('created.png')
+        expect(version.file_content_type).to eq('image/png')
+        expect(version.file_byte_size).to eq('sha-body'.bytesize)
+        expect(version.file_sha256).to eq(Digest::SHA256.hexdigest('sha-body'))
       end
 
       it 'returns 422 when the existing tag is not material/character' do
@@ -219,11 +269,33 @@ RSpec.describe 'Materials API', type: :request do
         expect(response).to have_http_status(:created)
         expect(json['url']).to eq('https://example.com/material-source')
       end
+
+      it 'rejects sha256-blocked file upload' do
+        sha256 = Digest::SHA256.hexdigest('blocked-body')
+        MaterialImportBlock.create!(match_kind: 'sha256',
+                                    sha256:,
+                                    reason: 'copyright_high_risk',
+                                    created_by_user: admin_user)
+
+        expect do
+          post '/materials', params: {
+            tag: 'material_blocked_create',
+            file: dummy_upload(filename: 'blocked.png', body: 'blocked-body')
+          }
+        end.not_to change(Material, :count)
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(json.fetch('errors')).to include(
+          'file' => ['抑止された素材です: copyright_high_risk']
+        )
+      end
     end
   end
 
   describe 'PUT /materials/:id' do
-    let!(:tag) { Tag.create!(tag_name: TagName.create!(name: 'material_update_old'), category: :material) }
+    let!(:tag) do
+      Tag.create!(tag_name: TagName.create!(name: 'material_update_old'), category: :material)
+    end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'old.png'))
     end
@@ -277,25 +349,26 @@ RSpec.describe 'Materials API', type: :request do
             'tag' => ['タグは必須です．'])
       end
 
-      it 'returns 422 when both file and url are blank' do
+      it 'keeps the existing file when file and url are omitted' do
         put "/materials/#{ material.id }", params: {
           tag: 'material_update_no_payload'
         }
 
-        expect(response).to have_http_status(:unprocessable_entity)
-        expect(json.fetch('errors')).to include(
-            'file' => ['ファイルまたは URL は必須です．'],
-            'url' => ['ファイルまたは URL は必須です．'])
+        expect(response).to have_http_status(:ok)
+        expect(material.reload.file.attached?).to be(true)
       end
 
       it 'updates tag, url, file, and updated_by_user' do
         old_blob_id = material.file.blob.id
 
-        put "/materials/#{ material.id }", params: {
-          tag: 'material_update_new',
-          url: 'https://example.com/updated-source',
-          file: dummy_upload(filename: 'updated.jpg', type: 'image/jpeg')
-        }
+        expect do
+          put "/materials/#{ material.id }", params: {
+            tag: 'material_update_new',
+            url: 'https://example.com/updated-source',
+            file: dummy_upload(filename: 'updated.jpg', type: 'image/jpeg'),
+            export_paths: { legacy_drive: '伊地知ニジカ/updated.jpg' }
+          }
+        end.to change(MaterialVersion, :count).by(2)
 
         expect(response).to have_http_status(:ok)
 
@@ -306,8 +379,15 @@ RSpec.describe 'Materials API', type: :request do
         expect(material.updated_by_user).to eq(member_user)
         expect(material.file.attached?).to be(true)
         expect(material.file.blob.id).not_to eq(old_blob_id)
+        expect(ActiveStorage::Blob.where(id: old_blob_id).exists?).to be(true)
         expect(material.file.blob.filename.to_s).to eq('updated.jpg')
         expect(material.file.blob.content_type).to eq('image/jpeg')
+        expect(material.version_no).to eq(2)
+        expect(material.material_versions.order(:version_no).last.event_type).to eq('update')
+        expect(material.material_export_items.first.export_path).to eq('伊地知ニジカ/updated.jpg')
+        expect(material.material_versions.order(:version_no).last.export_paths_json).to eq(
+          'legacy_drive' => '伊地知ニジカ/updated.jpg'
+        )
 
         expect(json['id']).to eq(material.id)
         expect(json['file']).to be_present
@@ -315,7 +395,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(json.dig('tag', 'name')).to eq('material_update_new')
       end
 
-      it 'purges the existing file when file is omitted and url is provided' do
+      it 'detaches the existing file without purging blob when url replaces file' do
         old_blob_id = material.file.blob.id
 
         put "/materials/#{ material.id }", params: {
@@ -331,9 +411,7 @@ RSpec.describe 'Materials API', type: :request do
         expect(material.updated_by_user).to eq(member_user)
         expect(material.file.attached?).to be(false)
 
-        expect(
-          ActiveStorage::Blob.where(id: old_blob_id).exists?
-        ).to be(false)
+        expect(ActiveStorage::Blob.where(id: old_blob_id).exists?).to be(true)
 
         expect(json['id']).to eq(material.id)
         expect(json['file']).to be_nil
@@ -341,11 +419,190 @@ RSpec.describe 'Materials API', type: :request do
         expect(json.dig('tag', 'name')).to eq('material_update_remove_file')
         expect(json['url']).to eq('https://example.com/updated-source')
       end
+
+      it 'does not increase version for the same snapshot update' do
+        MaterialVersionRecorder.record!(material:, event_type: :create,
+                                        created_by_user: member_user)
+
+        expect do
+          put "/materials/#{ material.id }", params: {
+            tag: 'material_update_old'
+          }
+        end.not_to change(MaterialVersion, :count)
+
+        expect(response).to have_http_status(:ok)
+        expect(material.reload.version_no).to eq(1)
+      end
+
+      it 'records update version when only export_path changes' do
+        MaterialVersionRecorder.record!(material:, event_type: :create,
+                                        created_by_user: member_user)
+
+        expect do
+          put "/materials/#{ material.id }", params: {
+            tag: 'material_update_old',
+            export_paths: { legacy_drive: '素材/only-path.png' }
+          }
+        end.to change(MaterialVersion, :count).by(1)
+
+        expect(response).to have_http_status(:ok)
+        expect(material.reload.material_export_items.first.export_path).to eq('素材/only-path.png')
+        expect(material.material_versions.order(:version_no).last.export_paths_json).to eq(
+          'legacy_drive' => '素材/only-path.png'
+        )
+      end
+
+      it 'removes export_path item when blank is submitted' do
+        MaterialExportItem.create!(material:, profile: 'legacy_drive',
+                                   export_path: '素材/remove.png',
+                                   created_by_user: member_user)
+        MaterialVersionRecorder.record!(material:, event_type: :create,
+                                        created_by_user: member_user)
+
+        expect do
+          put "/materials/#{ material.id }", params: {
+            tag: 'material_update_old',
+            export_paths: { legacy_drive: '' }
+          }
+        end.to change(MaterialExportItem, :count).by(-1)
+          .and change(MaterialVersion, :count).by(1)
+
+        expect(response).to have_http_status(:ok)
+        expect(material.reload.material_export_items).to be_empty
+        expect(material.material_versions.order(:version_no).last.export_paths_json).to eq({})
+      end
+
+      it 'rejects sha256-blocked replacement file' do
+        sha256 = Digest::SHA256.hexdigest('blocked-update')
+        MaterialImportBlock.create!(match_kind: 'sha256',
+                                    sha256:,
+                                    reason: 'source_owner_request',
+                                    created_by_user: admin_user)
+
+        put "/materials/#{ material.id }", params: {
+          tag: 'material_update_old',
+          file: dummy_upload(filename: 'blocked.png', body: 'blocked-update')
+        }
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(material.reload.file.blob.filename.to_s).to eq('old.png')
+      end
+    end
+  end
+
+  describe 'GET /materials/download.zip' do
+    let!(:tag_a) { Tag.create!(tag_name: TagName.create!(name: 'zip_a'), category: :material) }
+    let!(:tag_b) { Tag.create!(tag_name: TagName.create!(name: 'zip_b'), category: :material) }
+    let!(:material_a) do
+      build_material(tag: tag_a, user: member_user,
+                     file: dummy_upload(filename: 'a.png', body: 'zip-a'))
+    end
+    let!(:material_b) do
+      build_material(tag: tag_b, user: member_user,
+                     file: dummy_upload(filename: 'b.png', body: 'zip-b'))
+    end
+
+    before do
+      MaterialExportItem.create!(material: material_a, profile: 'legacy_drive',
+                                 export_path: '素材/a.png',
+                                 created_by_user: member_user)
+      MaterialExportItem.create!(material: material_b, profile: 'legacy_drive',
+                                 export_path: '素材/b.png',
+                                 created_by_user: member_user)
+    end
+
+    it 'uses material_export_items.export_path as ZIP entry paths' do
+      get '/materials/download.zip', params: { profile: 'legacy_drive' }
+
+      expect(response).to have_http_status(:ok)
+      expect(response.media_type).to eq('application/zip')
+      expect(response.body.b).to include('素材/a.png'.b)
+      expect(response.body.b).to include('素材/b.png'.b)
+    end
+
+    it 'filters by tag_id' do
+      get '/materials/download.zip', params: { profile: 'legacy_drive', tag_id: tag_a.id }
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body.b).to include('素材/a.png'.b)
+      expect(response.body.b).not_to include('素材/b.png'.b)
+    end
+
+    it 'does not include suppressed materials' do
+      material_b.update!(file_suppressed_at: Time.current,
+                         file_suppression_reason: 'copyright_high_risk')
+
+      get '/materials/download.zip', params: { profile: 'legacy_drive' }
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body.b).to include('素材/a.png'.b)
+      expect(response.body.b).not_to include('素材/b.png'.b)
+    end
+  end
+
+  describe 'PATCH /materials/:id/suppress_file' do
+    let!(:tag) do
+      Tag.create!(tag_name: TagName.create!(name: 'material_suppress'), category: :material)
+    end
+    let!(:material) do
+      build_material(tag:, user: member_user, file: dummy_upload(filename: 'suppress.png'))
+    end
+
+    it 'allows admin to suppress a file and records a suppress version' do
+      sign_in_as(admin_user)
+      MaterialVersionRecorder.record!(material:, event_type: :create,
+                                      created_by_user: member_user)
+
+      expect do
+        patch "/materials/#{ material.id }/suppress_file",
+              params: { reason: 'copyright_high_risk' }
+      end.to change(MaterialVersion, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+
+      material.reload
+      expect(material.file_suppressed_at).to be_present
+      expect(material.file_suppressed_by_user).to eq(admin_user)
+      expect(material.file_suppression_reason).to eq('copyright_high_risk')
+      expect(material.material_versions.order(:version_no).last.event_type).to eq('suppress')
+      expect(json['file']).to be_nil
+      expect(json['file_suppressed_at']).to be_present
+    end
+
+    it 'purges blob when purge=true is requested' do
+      sign_in_as(admin_user)
+      old_blob_id = material.file.blob.id
+      MaterialVersionRecorder.record!(material:, event_type: :create,
+                                      created_by_user: member_user)
+
+      expect do
+        patch "/materials/#{ material.id }/suppress_file",
+              params: { reason: 'copyright_takedown', purge: '1' }
+      end.to have_enqueued_job(ActiveStorage::PurgeJob)
+
+      expect(response).to have_http_status(:ok)
+
+      version = material.material_versions.order(:version_no).last
+      expect(version.event_type).to eq('suppress')
+      expect(version.file_blob_id).to eq(old_blob_id)
+      expect(version.file_filename).to eq('suppress.png')
+      expect(version.file_sha256).to be_present
+    end
+
+    it 'rejects member suppression' do
+      sign_in_as(member_user)
+
+      patch "/materials/#{ material.id }/suppress_file",
+            params: { reason: 'copyright_high_risk' }
+
+      expect(response).to have_http_status(:forbidden)
     end
   end
 
   describe 'DELETE /materials/:id' do
-    let!(:tag) { Tag.create!(tag_name: TagName.create!(name: 'material_destroy'), category: :material) }
+    let!(:tag) do
+      Tag.create!(tag_name: TagName.create!(name: 'material_destroy'), category: :material)
+    end
     let!(:material) do
       build_material(tag:, user: member_user, file: dummy_upload(filename: 'destroy.png'))
     end

frontend/src/App.tsx

@@ -69,7 +69,7 @@ const RouteTransitionWrapper = ({ user, setUser }: {
 	  <Route path="/materials" element={<MaterialBasePage/>}>
 	    <Route index element={<MaterialListPage/>}/>
 	    <Route path="new" element={<MaterialNewPage/>}/>
-	    <Route path=":id" element ={<MaterialDetailPage/>}/>
+	    <Route path=":id" element ={<MaterialDetailPage user={user}/>}/>
 	  </Route>
 	  {/* <Route path="/materials/search" element={<MaterialSearchPage/>}/> */}
 	  <Route path="/wiki" element={<WikiSearchPage/>}/>

frontend/src/pages/materials/MaterialDetailPage.test.tsx

@@ -8,6 +8,7 @@ import { renderWithProviders } from '@/test/render'
 
 const api = vi.hoisted (() => ({
   apiGet: vi.fn (),
+  apiPatch: vi.fn (),
   apiPut: vi.fn (),
 }))
 
@@ -26,7 +27,7 @@ vi.mock ('@/components/ui/use-toast', () => toastApi)
 const renderPage = () =>
   renderWithProviders (
       <Routes>
-        <Route path="/materials/:id" element={<MaterialDetailPage/>}/>
+        <Route path="/materials/:id" element={<MaterialDetailPage user={null}/>}/>
       </Routes>,
       { route: '/materials/8' },
   )
@@ -73,6 +74,7 @@ describe ('MaterialDetailPage', () => {
     const textboxes = screen.getAllByRole ('textbox')
     fireEvent.change (textboxes[0], { target: { value: 'new' } })
     fireEvent.change (textboxes[1], { target: { value: 'https://example.com/ref' } })
+    fireEvent.change (textboxes[2], { target: { value: '素材/new.png' } })
     fireEvent.click (screen.getByRole ('button', { name: '更新' }))
 
     await waitFor (() => {
@@ -81,6 +83,7 @@ describe ('MaterialDetailPage', () => {
     const formData = api.apiPut.mock.calls[0]?.[1] as FormData
     expect (formData.get ('tag')).toBe ('new')
     expect (formData.get ('url')).toBe ('https://example.com/ref')
+    expect (formData.get ('export_paths[legacy_drive]')).toBe ('素材/new.png')
     expect (toastApi.toast).toHaveBeenCalledWith ({ title: '更新成功!' })
   })
 })

frontend/src/pages/materials/MaterialDetailPage.tsx

@@ -13,22 +13,23 @@ import MainArea from '@/components/layout/MainArea'
 import { Button } from '@/components/ui/button'
 import { toast } from '@/components/ui/use-toast'
 import { SITE_TITLE } from '@/config'
-import { apiGet, apiPut } from '@/lib/api'
+import { apiGet, apiPatch, apiPut } from '@/lib/api'
 import { inputClass } from '@/lib/utils'
 import { useValidationErrors } from '@/lib/useValidationErrors'
 
 import type { FC } from 'react'
 
-import type { Material, Tag } from '@/types'
+import type { Material, Tag, User } from '@/types'
 
 type MaterialWithTag = Material & { tag: Tag }
 
-type MaterialFormField = 'tag' | 'file' | 'url'
+type MaterialFormField = 'tag' | 'file' | 'url' | 'exportPaths'
 
 
-const MaterialDetailPage: FC = () => {
+const MaterialDetailPage: FC<{ user: User | null }> = ({ user }) => {
   const { id } = useParams ()
 
+  const [exportPath, setExportPath] = useState ('')
   const [file, setFile] = useState<File | null> (null)
   const [filePreview, setFilePreview] = useState ('')
   const [loading, setLoading] = useState (false)
@@ -49,6 +50,7 @@ const MaterialDetailPage: FC = () => {
       formData.append ('file', file)
     if (url.trim ())
       formData.append ('url', url)
+    formData.append ('export_paths[legacy_drive]', exportPath)
 
     try
     {
@@ -68,6 +70,30 @@ const MaterialDetailPage: FC = () => {
     }
   }
 
+  const handleSuppress = async () => {
+    const reason = window.prompt ('抑止理由を入力してください。')
+    if (reason == null || reason.trim () === '')
+      return
+    if (!window.confirm ('素材ファイルを抑止します。表示と ZIP export から除外されます。'))
+      return
+
+    try
+    {
+      const data = await apiPatch<Material> (
+	  `/materials/${ id }/suppress_file`,
+	  { reason },
+      )
+      setMaterial (data)
+      setFile (null)
+      setFilePreview ('')
+      toast ({ title: '抑止しました' })
+    }
+    catch
+    {
+      toast ({ title: '抑止に失敗しました' })
+    }
+  }
+
   useEffect (() => {
     if (!(id))
       return
@@ -82,11 +108,10 @@ const MaterialDetailPage: FC = () => {
 	if (data.file && data.contentType)
 	  {
 	    setFilePreview (data.file)
-	    setFile (new File ([await (await fetch (data.file)).blob ()],
-			       data.file,
-			       { type: data.contentType }))
+	    setFile (null)
 	  }
 	setURL (data.url ?? '')
+	setExportPath (data.exportPaths.legacyDrive ?? '')
       }
       finally
       {
@@ -111,7 +136,14 @@ const MaterialDetailPage: FC = () => {
 		    withCount={false}/>
 	      </PageTitle>
 
-	      {(material.file && material.contentType) && (
+	      {material.fileSuppressedAt && (
+		  <div className="mb-4 rounded border border-red-300 bg-red-50 p-3 text-red-700">
+		    <span>素材ファイルは抑止済みです。</span>
+		    {material.fileSuppressionReason && (
+			<span> 理由: {material.fileSuppressionReason}</span>)}
+		  </div>)}
+
+	      {(!material.fileSuppressedAt && material.file && material.contentType) && (
 		  (/image\/.*/.test (material.contentType) && (
 		      <img src={material.file} alt={material.tag.name || undefined}/>))
 		  || (/video\/.*/.test (material.contentType) && (
@@ -189,13 +221,36 @@ const MaterialDetailPage: FC = () => {
 			      className={inputClass (invalid)}/>)}
 		    </FormField>
 
+		    <FormField
+			label="ZIP 出力パス"
+			messages={fieldErrors.exportPaths}>
+		      {({ describedBy, invalid }) => (
+			  <input
+			      type="text"
+			      value={exportPath}
+			      onChange={e => setExportPath (e.target.value)}
+			      placeholder="伊地知ニジカ/表情/泣き.png"
+			      aria-describedby={describedBy}
+			      aria-invalid={invalid}
+			      className={inputClass (invalid)}/>)}
+		    </FormField>
+
 		    {/* 送信 */}
-		    <Button
-			onClick={handleSubmit}
-			className="px-4 py-2 bg-blue-600 text-white rounded disabled:bg-gray-400"
-			disabled={sending}>
-		      更新
-		    </Button>
+		    <div className="flex flex-wrap gap-2">
+		      <Button
+			  onClick={handleSubmit}
+			  className="px-4 py-2 bg-blue-600 text-white rounded disabled:bg-gray-400"
+			  disabled={sending}>
+			更新
+		      </Button>
+		      {user?.role === 'admin' && !material.fileSuppressedAt && (
+			  <Button
+			      type="button"
+			      variant="destructive"
+			      onClick={handleSuppress}>
+			    ファイルを抑止
+			  </Button>)}
+		    </div>
 		  </div>
 		</Tab>
 	      </TabGroup>

frontend/src/pages/materials/MaterialListPage.tsx

@@ -9,7 +9,7 @@ import PageTitle from '@/components/common/PageTitle'
 import SectionTitle from '@/components/common/SectionTitle'
 import SubsectionTitle from '@/components/common/SubsectionTitle'
 import MainArea from '@/components/layout/MainArea'
-import { SITE_TITLE } from '@/config'
+import { API_BASE_URL, SITE_TITLE } from '@/config'
 import { apiGet } from '@/lib/api'
 
 import type { FC } from 'react'
@@ -30,10 +30,15 @@ const MaterialCard = ({ tag }: { tag: TagWithMaterial }) => {
 	  to={`/materials/${ tag.material.id }`}
 	  className="block w-40 h-40">
 	<div
-	    className="w-full h-full overflow-hidden rounded-xl shadow
-		       text-center content-center text-4xl"
+	    className={`w-full h-full overflow-hidden rounded-xl shadow
+			text-center content-center text-4xl ${
+			tag.material.fileSuppressedAt
+			? 'border-2 border-red-300 bg-red-50 text-base text-red-700'
+			: '' }`}
 	    style={{ fontFamily: 'Nikumaru' }}>
-	  {(tag.material.contentType && /image\/.*/.test (tag.material.contentType))
+	  {tag.material.fileSuppressedAt
+	   ? <span>抑止済み</span>
+	   : (tag.material.contentType && /image\/.*/.test (tag.material.contentType))
 	   ? <img src={tag.material.file || undefined}/>
 	   : <span>照会</span>}
 	</div>
@@ -108,7 +113,7 @@ const MaterialListPage: FC = () => {
 
 		  <MaterialCard tag={tag}/>
 
-		  <div className="ml-2">
+		  <div className="ml-2 overflow-x-auto pb-2">
 		    {tag.children.map (c2 => (
 			<Fragment key={c2.id}>
 			  <SectionTitle>
@@ -159,7 +164,11 @@ const MaterialListPage: FC = () => {
 		  <p>もしくは……</p>
 		  <ul>
 		    <li><PrefetchLink to="/materials/new">素材を新規追加する</PrefetchLink></li>
-		    {/* <li><a href="#">すべての素材をダウンロードする</a></li> */}
+		    <li>
+		      <a href={`${ API_BASE_URL }/materials/download.zip?profile=legacy_drive`}>
+			すべての素材をダウンロードする
+		      </a>
+		    </li>
 		  </ul>
 		</>))}
       </MainArea>)

frontend/src/pages/materials/MaterialNewPage.tsx

@@ -17,7 +17,7 @@ import { useValidationErrors } from '@/lib/useValidationErrors'
 
 import type { FC } from 'react'
 
-type MaterialFormField = 'tag' | 'file' | 'url'
+type MaterialFormField = 'tag' | 'file' | 'url' | 'exportPaths'
 
 
 const MaterialNewPage: FC = () => {
@@ -32,6 +32,7 @@ const MaterialNewPage: FC = () => {
   const [sending, setSending] = useState (false)
   const [tag, setTag] = useState (tagQuery)
   const [url, setURL] = useState ('')
+  const [exportPath, setExportPath] = useState ('')
   const { baseErrors, fieldErrors, clearValidationErrors, applyValidationError } =
       useValidationErrors<MaterialFormField> ()
 
@@ -45,6 +46,7 @@ const MaterialNewPage: FC = () => {
       formData.append ('file', file)
     if (url)
       formData.append ('url', url)
+    formData.append ('export_paths[legacy_drive]', exportPath)
 
     try
     {
@@ -133,6 +135,20 @@ const MaterialNewPage: FC = () => {
 		    className={inputClass (invalid)}/>)}
 	  </FormField>
 
+	  <FormField
+	      label="ZIP 出力パス"
+	      messages={fieldErrors.exportPaths}>
+	    {({ describedBy, invalid }) => (
+		<input
+		    type="text"
+		    value={exportPath}
+		    onChange={e => setExportPath (e.target.value)}
+		    placeholder="伊地知ニジカ/表情/泣き.png"
+		    aria-describedby={describedBy}
+		    aria-invalid={invalid}
+		    className={inputClass (invalid)}/>)}
+	  </FormField>
+
 	  {/* 送信 */}
 	  <Button
 	      onClick={handleSubmit}

frontend/src/test/factories.ts

@@ -71,16 +71,21 @@ export const buildWikiPage = (overrides: Partial<WikiPage> = {}): WikiPage => ({
 })
 
 export const buildMaterial = (overrides: Partial<Material> = {}): Material => ({
-  id:            1,
-  tag:           buildTag (),
-  file:          null,
-  url:           null,
-  wikiPageBody:  null,
-  contentType:   null,
-  createdAt:     '2026-01-02T03:04:05.000Z',
-  createdByUser: { id: 1, name: 'creator' },
-  updatedAt:     '2026-01-03T03:04:05.000Z',
-  updatedByUser: { id: 2, name: 'updater' },
+  id:                    1,
+  versionNo:             1,
+  tag:                   buildTag (),
+  file:                  null,
+  url:                   null,
+  wikiPageBody:          null,
+  contentType:           null,
+  fileSuppressedAt:      null,
+  fileSuppressionReason: null,
+  exportPaths:           {},
+  exportItems:           [],
+  createdAt:             '2026-01-02T03:04:05.000Z',
+  createdByUser:         { id: 1, name: 'creator' },
+  updatedAt:             '2026-01-03T03:04:05.000Z',
+  updatedByUser:         { id: 2, name: 'updater' },
   ...overrides,
 })
 

frontend/src/types.ts

@@ -66,16 +66,27 @@ export type FetchNicoTagsOrder = `${ FetchNicoTagsOrderField }:${ 'asc' | 'desc'
 export type FetchNicoTagsOrderField = 'name' | 'created_at' | 'updated_at'
 
 export type Material = {
-    id:             number
-    tag:            Tag
-    file:           string | null
-    url:            string | null
-    wikiPageBody?:  string | null
-    contentType:    string | null
-    createdAt:      string
-    createdByUser:  { id: number; name: string }
-    updatedAt:      string
-    updatedByUser:  { id: number; name: string } }
+    id:                     number
+    versionNo:              number
+    tag:                    Tag
+    file:                   string | null
+    url:                    string | null
+    wikiPageBody?:          string | null
+    contentType:            string | null
+    fileSuppressedAt:       string | null
+    fileSuppressionReason:  string | null
+    exportPaths:            Record<string, string>
+    exportItems:            MaterialExportItem[]
+    createdAt:              string
+    createdByUser:          { id: number; name: string }
+    updatedAt:              string
+    updatedByUser:          { id: number; name: string } }
+
+export type MaterialExportItem = {
+    id:          number
+    profile:     string
+    exportPath:  string
+    enabled:     boolean }
 
 export type Menu = MenuItem[]