Allow access to SSLCert/Context from within handler

[gnunicorn]

I am currently trying to implement a basic SSL mutual authentication mechanism using hyper. Through using openssl and making my own SSLContext I am already able to require the client to send a certificate and reject as the server seems appropriate. But within the SSL-verify callback I can't alter the context of request. So, in order to be able to not only have a yes-no but an actual "this certificate belongs to that user", I'd need support to access the ssl certificate/context from within the handler so the application code can decide based on that, but that seems impossible at the moment as they are encapsulated away.

I can provide my code if anyone cares and if someone tells me, what changes would be accepted as a PR would also be willing to make the changes myself. Unless I have missed some way to make that happen.

[seanmonstar]

To be sure, you need to check the SslContext from within Handler::handle?

[gnunicorn]

@seanmonstar, Unless you have any other idea, how I could figure out from the handler, what the SSLCert send by the client is... Yes.

[seanmonstar]

I'm guessing you want to access http://sfackler.github.io/rust-openssl/doc/v0.6.4/openssl/ssl/struct.SslStream.html#method.get_peer_certificate

Perhaps adding a downcast_ref sort of function to Request, so that you could get a &SslStream (assuming you're using openssl).

pub fn downcast_ref<T: NetworkStream>(&self) -> Option<&T> {

}