#306

backend/app/controllers/materials_controller.rb

@@ -1,6 +1,7 @@
 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
@@ -203,6 +204,22 @@ class MaterialsController < ApplicationController
     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 apply_file_sha256! material, file_sha256
     return if file_sha256.blank?
     return unless material.file.attached?
@@ -222,7 +239,8 @@ class MaterialsController < ApplicationController
       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) }
+      file_sha256: blob.metadata['sha256'] ||
+                   MaterialFileSha256.from_blob(blob, allow_download: true) }
   end
 
   def render_material_import_block block

backend/app/services/material_file_sha256.rb

@@ -1,16 +1,25 @@
 require 'digest'
 
 class MaterialFileSha256
-  def self.from_blob blob
+  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

backend/app/services/material_version_recorder.rb

@@ -49,9 +49,6 @@ class MaterialVersionRecorder < VersionRecorder
     return @file_snapshot if @file_snapshot
     return empty_file_snapshot unless blob
 
-    blob.metadata['sha256'] ||= MaterialFileSha256.from_blob(blob)
-    blob.save! if blob.changed?
-
     { file_blob_id: blob.id,
       file_filename: blob.filename.to_s,
       file_content_type: blob.content_type,

backend/app/services/material_zip_exporter.rb

@@ -5,9 +5,19 @@ require 'zlib'
 # 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'
@@ -35,15 +45,22 @@ class MaterialZipExporter
 
     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: material.file.blob.download,
+                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
@@ -51,6 +68,20 @@ class MaterialZipExporter
     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