engine.py 文件源码

def select_template(self, template_name_list, dirs=_dirs_undefined):
        """
        Given a list of template names, returns the first that can be loaded.
        """
        if dirs is _dirs_undefined:
            # Do not set dirs to None here to avoid triggering the deprecation
            # warning in get_template.
            pass
        else:
            warnings.warn(
                "The dirs argument of select_template is deprecated.",
                RemovedInDjango20Warning, stacklevel=2)

        if not template_name_list:
            raise TemplateDoesNotExist("No template names provided")
        not_found = []
        for template_name in template_name_list:
            try:
                return self.get_template(template_name, dirs)
            except TemplateDoesNotExist as exc:
                if exc.args[0] not in not_found:
                    not_found.append(exc.args[0])
                continue
        # If we get here, none of the templates could be loaded
        raise TemplateDoesNotExist(', '.join(not_found))