#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