Add connection metadata to HTTP::Server::Response

[straight-shoota]

This PR adds methods #local_address and #remote_address address to HTTP::Server::Response.

I'm not entirely sure whether the method's return type should be nilable. It's not very typical to have a Response not wrapping a socket. This is mostly used as mockup for specs. Maybe we can avoid forcing usually unnecessary nil-checks in actual code. This could be done either by raising (though there should probably also be a non-raising option) or returning some default address if the IO does not provide one.

Closes #5784
Based on #5869

[straight-shoota]

I'm not sure anymore about whether this is a good solution. It's not ideal, but at least relatively easy compared to a bigger refactor (see #5784 (comment)).

[asterite]

Yeah, maybe having separate Request types is the way to go.

[fuegito]

Hi all,
is there a chance that this PR will be merged any time soon? I just can't understand why this hasn't been added to the stdlib from the beginning. It is a no-brainer to have this feature since it is anything but an exotic requirement to know (e.g. for logging) the connecting ip.

Note that i am not interested in the (real) client ip (i know this is more complicated) but in the remote socket source ip and yes, i know the workarounds with adding an HTTP-Header through a reverse proxy.

BTW: how is this patch applied in the most canonical way (best practice) as long as it isn't merged?

Thanks for your reply & best regards,
Stefan

[straight-shoota]

I don't think this should be merged soon. @asterite's suggestion to separate HTTP::Request seems the way to go IMHO.

You shouldn't apply this patch directly to your local std lib copy, but rather add a monkey patch in your application code:

class HTTP::Server::Response
  # Returns the local address of the network socket used by this connection.
  #
  # This can be useful if the server listens on multiple sockets.
  def local_address : Socket::Address?
    if (socket = @io).responds_to? :local_address
      socket.local_address
    end
  end
 
  # Returns the remote address of the network socket used by this connection.
  #
  # This is not necessarily the address of the original requestor but the last
  # proxy (e.g. a load balancer).
  def remote_address : Socket::Address?
    if (socket = @io).responds_to? :remote_address
      socket.remote_address
    end
  end
end

[straight-shoota]

You probably won't need any of the changes in the first commit, they'll be in 0.25.0 (see #5869).

[fuegito]

Great, thanks a lot!

BTW: I am impressed by the quick response I received here!

[straight-shoota]

I'll close this. Let's discuss a more general solution regarding HTTP::Request.