$body_bytes_sent compute bigger in HTTP2.0 then HTTP1.X

[cjhust1986@…]

source file：2000Byte;
HTTP1.0/HTTP1.1: $body_bytes_sent = 2000byte, I think it's correct
HTTP2.0: $body_bytes_sent = 2300byte(uncertainty) > 2000byte, I think it's wrong

I know the fream in HTTP2.0 causes this problem, the frame include NGX_HTTP_V2_FRAME_HEADER_SIZE, HTTP header...

I think this method is wrong, $body_bytes_sent is not $bytes_sent.

look forward to your reply

[Valentin V. Bartenev]

A quote from ​the documentation:

$body_bytes_sent - number of bytes sent to a client, not counting the response header

In other words: $body_bytes_sent = $bytes_sent - response_header_size, where the response_header_size value in case of HTTP/2 is the size of the response HEADERS block, not the data frame headers.

That's it.

Of course it's bigger, since HTTP/2 framing adds additional overhead (like chunked transfer encoding in HTTP/1.1).

[Maxim Dounin]

See also #1596.