This allows any application to upgrade the protocol options without
having to restart the listener. This is most useful to update the
dispatch list of HTTP servers, for example.
The upgrade is done at the acceptor level, meaning only new connections
receive the new protocol options.
This is a big change in the internal cowboy API. This should not
have any impact on existing applications as only the acceptor is
expected to use these API calls.
The function cowboy_listener:wait/3 has been removed. max_connections
checking now occurs directly in cowboy_listener:add_connection/3.
If the pool is full and the acceptor has to wait, then it doesn't
return, waiting for a free space to be available.
To accomodate these changes, it is now cowboy_listener that will
inform the new connection that it is ready by sending {shoot, self()}.
This should be a great improvement to the latency of responses as
there is one less message to wait for before the request process
can do its work.
Overall the performance under heavy load should also be improved as
we greatly reduce the number of messages sent between the acceptor
and the listener process.
We try to send a 500 error only if we didn't send the response
headers yet. If they were, then we have no way to be sure the
response was fully sent, nor should we assume anything about
how this will be handled client-side, so we do nothing more
and in both cases close the connection.
Also add the new 'put_path' metadata information to the request
before entering the put_resource step (which proceeds to call
content_types_accepted and then the chosen content type's callback,
which is expected to use the 'put_path' value as the path to the new
resource instead of the original request path, because it may have
been changed by the create_path call.
resp_body is set by cowboy_http_req:set_resp_body/2 which accepts
the input type iodata(). Update the resp_body field to use the same
type. Also update the cowboy_http_req:has_resp_body/2 function to
use the iolist_size/1 which works with both binary() and iolist()
values instead of the byte_size/1 function which only works with
binary() values.
Fix pattern in case statement that was intended
to strip away the first comma separating the
values in the variance header.
Update generation of variance list to use more
idiomatic erlang. Pattern match on list structure
over using erlang:length/1 to compute length.
