Define and use an auth context structure

auth/interface.go

@@ -4,6 +4,18 @@ import (
 	"net/http"
 )
 
+var AuthCtxKey = &contextKey{"auth"}
+
+type contextKey struct {
+	name string
+}
+
+type AuthContext struct {
+	AuthMethod string
+	UserName   string
+	// TODO more?
+}
+
 // Abstracts the authentication backend for the server.
 type AuthProvider interface {
 	// Returns HTTP middleware for performing authentication.