code: def generate_pages_by_file():
      
      from veripress import app
      from veripress.model import storage
      from veripress.model.parsers import get_standard_format_name
      from veripress.helpers import traverse_directory
  
      deploy_dir = get_deploy_dir()
  
      def copy_file(src, dst):
          makedirs(os.path.dirname(dst), mode=0o755, exist_ok=True)
          shutil.copyfile(src, dst)
  
      with app.app_context(), app.test_client() as client:
          root_path = os.path.join(app.instance_path, 'pages')
          for path in traverse_directory(root_path):
              # e.g. 'a/b/c/index.md'
              rel_path = os.path.relpath(path, root_path)
              # e.g. ('a/b/c/index', '.md')
              filename, ext = os.path.splitext(rel_path)
              if get_standard_format_name(ext[1:]) is not None:
                  # is source of custom page
                  rel_url = filename.replace(os.path.sep, '/') + '.html'
                  page = storage.get_page(rel_url, include_draft=False)
                  if page is not None:
                      # it's not a draft, so generate the html page
                      makedirs(os.path.join(deploy_dir,
                                            os.path.dirname(rel_path)),
                               mode=0o755, exist_ok=True)
                      with open(os.path.join(deploy_dir, filename + '.html'),
                                'wb') as f:
                          f.write(client.get('/' + rel_url).data)
                  if app.config['PAGE_SOURCE_ACCESSIBLE']:
                      copy_file(path, os.path.join(deploy_dir, rel_path))
              else:
                  # is other direct files
                  copy_file(path, os.path.join(deploy_dir, rel_path))
docs: Generates custom pages of 'file' storage type.