[4.x] 6121 100 continue request reset fix

[danielkec]

Fixes #6121

[klustria]

Change looks good. However, just one question which I also posted in #6121

I was encountering issue reading the http status after a continue-100 response and found that the main reason for this is because of this: https://github.com/helidon-io/helidon/blob/main/nima/webserver/webserver/src/main/java/io/helidon/nima/webserver/http1/Http1Connection.java#L58 where there is extra /r/n at the end of Continue 100 response. Prior to the expect-continue-100 recent change, there is only 1 /r/n but in the recent code there are 2. Is this a requirement to have 2x CRLF?

I can of course skip/ignore the remaining lines, but just wondering if this is a requirement.

[klustria]

I will approve this anyway because I have tested the change to be working fine after applying it in my local branch. Also, I can deal with the extra CRLF, but would just like to verify if that is really needed for a 100-Continue response. Thanks for the quick turnaround, even on your weekend.

[danielkec]

Hi @klustria afaik double CRLF is mandatory, see RFC 2616

Response      = Status-Line *(( general-header | response-header | entity-header ) CRLF)  
                       CRLF        (* <---- Second *)
                       [ message-body ]          

Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase CRLF (* <----- First *)

[klustria]

Thanks @danielkec!