'checkExpectation' 事件

每次收到带有 HTTP Expect 请求头的请求时触发,其中值不是 100-continue。 如果未监听此事件,则服务器将根据需要自动响应 417 Expectation Failed

请注意,在触发和处理此事件时,不会触发 'request' 事件。

Emitted each time a request with an HTTP Expect header is received, where the value is not 100-continue. If this event is not listened for, the server will automatically respond with a 417 Expectation Failed as appropriate.

Note that when this event is emitted and handled, the 'request' event will not be emitted.