fix: Fix username extraction in the TLS handler

cmd/rio/main.go

@@ -24,26 +24,14 @@ import (
 	"github.com/urfave/cli/v2"
 )
 
-// Extract the username from the domain name @domain that we're processing
-// at the moment.
-func extractUsername(pagesDomain, domain string) string {
-	suffixlessDomain := strings.TrimSuffix(domain, "."+pagesDomain)
-	usernameParts := strings.Split(suffixlessDomain, ".")
-	if len(usernameParts) == 1 {
-		return usernameParts[0]
-	}
-
-	return strings.Join(usernameParts, ".")
-}
-
 func handleSubdomain(pagesDomain, domain, cname, path, giteaUrl, defaultCsp string, giteaClient *repo.GiteaClient, w http.ResponseWriter) {
 	username := ""
 	if cname != "" {
 		// If we are accessed via a CNAME, then CNAME contains our <user>.<pages domain> value.
-		username = extractUsername(pagesDomain, cname)
+		username = dns.ExtractUsername(pagesDomain, cname)
 	} else {
 		// If we are directly accessed, then domain contains our <user>.<pages domain> value.
-		username = extractUsername(pagesDomain, domain)
+		username = dns.ExtractUsername(pagesDomain, domain)
 	}
 
 	// Strip the leading /

cmd/rio/main_test.go

@@ -1,23 +0,0 @@
-package main
-
-import "testing"
-
-func TestExtractUsernameSimple(t *testing.T) {
-	username := extractUsername(
-		"pages.local",
-		"papatutuwawa.pages.local",
-	)
-	if username != "papatutuwawa" {
-		t.Fatalf("Unexpected username: '%s'", username)
-	}
-}
-
-func TestExtractUsernameDot(t *testing.T) {
-	username := extractUsername(
-		"pages.local",
-		"polynom.me.pages.local",
-	)
-	if username != "polynom.me" {
-		t.Fatalf("Unexpected username: '%s'", username)
-	}
-}