# *******************************
# Decorator to wrap task_* method
# *******************************
def integrity(integrity_func):
    """
    Args:
        :param integrity_func: couldb callable or string contains name of
            method to call
    """
    def build_decorator(func):
        @wraps(func)
        def func_wrapper(self, grab, task):
            try:
                if isinstance(integrity_func, str):
                    getattr(self, integrity_func)(grab)
                else:
                    integrity_func(grab)
            except (PageNotFound, UnexpectedHttpCode, UnexpectedContent) as ex:
                yield task.clone()
                self.stat.inc(ex.__class__.__name__)
                logging.error('', exc_info=ex)
            else:
                result = func(self, grab, task)
                if result is not None:
                    for event in result:
                        yield event
        return func_wrapper
    return build_decorator


# ****************
# Example of usage
# ****************
class SomeSpider(Spider):
    def basic_integrity(self, grab):
            if grab.doc.code == 404:
                raise PageNotFound('HTTP code 404')
            elif grab.doc.code != 200:
                import pdb; pdb.set_trace()
                raise UnexpectedHttpCode('HTTP code: %d' % grab.doc.code)
            elif not grab.doc.text_search('<div class="copyright_text">'):
                import pdb; pdb.set_trace()
                raise UnexpectedContent('Copyright message not found')

	@integrity('basic_integrity')
    def task_page(self, grab, task):
    	# business logic