摘要
A condition in the request headers evaluated to false on the server.
何时发生
Returned when If-Match / If-Unmodified-Since preconditions are not met.
常见原因
- Resource changed since the ETag was fetched
- Stale If-Match / If-Unmodified-Since value
解决方法
- Refetch the current ETag and retry
- Remove the failing precondition if not needed