#306

backend/app/services/google_drive/api_client.rb

@@ -26,13 +26,19 @@ module GoogleDrive
 
     def list_material_files_under_folder folder_id
       files = []
+      each_material_file_under_folder(folder_id) { |entry| files << entry }
+      files
+    end
+
+    def each_material_file_under_folder folder_id
+      return enum_for(__method__, folder_id) unless block_given?
+
       walk_folder(folder_id, nil) do |entry, relative_path|
         next if entry['mimeType'] == FOLDER_MIME_TYPE
         next if native_file?(entry['mimeType'])
 
-        files << build_file_entry(entry, relative_path)
+        yield build_file_entry(entry, relative_path)
       end
-      files
     end
 
     def fetch_material_file file_id
@@ -44,9 +50,10 @@ module GoogleDrive
 
     def download_to_tempfile file_id, filename:
       tempfile = Tempfile.new(['material-sync', File.extname(filename.to_s)])
+      tempfile.binmode
       request_binary("/files/#{ file_id }",
                      { alt: 'media', supportsAllDrives: true }) do |chunk|
-        tempfile.write(chunk)
+        tempfile.write(chunk.b)
       end
       tempfile.rewind
       tempfile
@@ -139,7 +146,7 @@ module GoogleDrive
         end
 
         response.read_body do |chunk|
-          yield chunk
+          yield chunk.b
         end
       end
     end