- secure-connection? #!optional booleanparameter
#t when the current connection is a secure one (SSL), #f if it isn't (regular HTTP). This pertains only to the direct connection itself, so if Spiffy is behind a proxy this will be #f even if the proxy itself is connected to the client over SSL.
One way to get around this is to always add a custom header to your reverse proxy's configuration file. Then you can read this out in Spiffy and set secure-connection? to #t or #f, as well as updating the request URI's scheme. There is no standardized header for this, so the default Spiffy won't do this.
An easier way around this is to set up two spiffies listening on different ports and configure one to have secure-connection? set to #t, which you redirect incoming HTTPS requests to.
This parameter may disappear or change in the future, when there are more smart people using Spiffy who know how to deal with this or the Spiffy maintainer has a moment of clarity and decides how to do this cleanly.