在flask文档中有一个钩子函数的例子,当没有找到瓶子定义的url端点时,它允许通过被调用为url_for
函数添加自定义行为。如果没有匹配的用户定义的url端点,程序员可以添加自定义端点或重新引发异常(使用原始上下文)。
def external_url_handler(error, endpoint, values):
"Looks up an external URL when `url_for` cannot build a URL."
# This is an example of hooking the build_error_handler.
# Here, lookup_url is some utility function you've built
# which looks up the endpoint in some external URL registry.
url = lookup_url(endpoint, **values)
if url is None:
# External lookup did not have a URL.
# Re-raise the BuildError, in context of original traceback.
exc_type, exc_value, tb = sys.exc_info()
if exc_value is error:
raise exc_type, exc_value, tb
else:
raise error
# url_for will use this result, instead of raising BuildError.
return url
app.url_build_error_handlers.append(external_url_handler)
此代码段似乎是python2代码,因为raise exc_type, exc_value, tb
行而导致python3失败。
python2和python3文档列出了raise语句的不同参数。
将此代码段转换为python3的正确方法是什么?
答案 0 :(得分:1)
这在the raise
statement的文档中指定:
您可以使用
with_traceback()
异常方法(返回相同的异常实例,并将其traceback设置为其参数),在一个步骤中创建异常并设置您自己的回溯,如下所示:raise Exception("foo occurred").with_traceback(tracebackobj)
所以,在你的情况下,那将是:
raise exc_type(exc_value).with_traceback(tb)