Previously, it was allocated from a connection pool and
was selectively freed for an idle keepalive connection.
The goal is to put coupled things in one chunk of memory,
and to simplify handling of request objects.
The request object will not be created until SSL handshake is complete.
This simplifies adding another connection handler that does not need
request object right after handshake (e.g., SPDY).
There are also a few more intentional effects:
- the "client_header_buffer_size" directive will be taken from the
server configuration that was negotiated by SNI;
- SSL handshake errors and timeouts are not logged into access log
as bad requests;
- ngx_ssl_create_connection() is not called until the first byte of
ClientHello message was received. This also decreases memory
consumption if plain HTTP request is sent to SSL socket.
Previously, only the first request in a connection was assigned the
configuration selected by SNI. All subsequent requests initially
used the default server's configuration, ignoring SNI, which was
wrong.
Now all subsequent requests in a connection will initially use the
configuration selected by SNI. This is done by storing a pointer
to configuration in http connection object. It points to default
server's configuration initially, but changed upon receipt of SNI.
(The request's configuration can be further refined when parsing
the request line and Host: header.)
This change was not made specific to SNI as it also allows slightly
faster access to configuration without the request object.
This allows to proxy WebSockets by using configuration like this:
location /chat/ {
proxy_pass http://backend;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
}
Connection upgrade is allowed as long as it was requested by a client
via the Upgrade request header.
This includes handling of ETag headers (if present in a response) with
basic support for If-Match, If-None-Match conditionals in not modified
filter.
Note that the "r->headers_out.last_modified_time == -1" check in the not
modified filter is left as is intentionally. It's to prevent handling
of If-* headers in case of proxy without cache (much like currently
done with If-Modified-Since).
It wasn't enforced for a long time, and there are reports that people
use up to 100 simultaneous subrequests now. As this is a safety limit
to prevent loops, it's raised accordingly.
