"net/http"
	"regexp"
	"strings"
)

var (
	// De-facto standard header keys.
	xForwardedFor    = http.CanonicalHeaderKey("X-Forwarded-For")
	xForwardedHost   = http.CanonicalHeaderKey("X-Forwarded-Host")
	xForwardedPort   = http.CanonicalHeaderKey("X-Forwarded-Port")
	xForwardedProto  = http.CanonicalHeaderKey("X-Forwarded-Proto")
	xForwardedScheme = http.CanonicalHeaderKey("X-Forwarded-Scheme")