add wildcard domain redirect support

1 files changed, 19 insertions, 3 deletions

diff --git a/internal/server/server.go b/internal/server/server.go
index b174c0c..6ef715b 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -8,6 +8,7 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
+	"regexp"
 	"slices"
 	"strconv"
 	"strings"
@@ -184,11 +185,26 @@ func New(runtimeConfig *Config, log *log.Logger) (*Server, error) {
 	}
 
 	if runtimeConfig.Redirect {
+		re := regexp.MustCompile(
+			"^(.*)\\." + strings.ReplaceAll(config.WildcardDomain, ".", `\.`) + "$",
+		)
+		replace := "${0}." + config.Domains[0]
 		loggingMux.Handle(config.BaseURL.Hostname()+"/", mux)
 		loggingMux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
-			path, _ := website.CanonicalisePath(r.URL.Path)
-			newURL := config.BaseURL.JoinPath(path)
-			http.Redirect(w, r, newURL.String(), http.StatusMovedPermanently)
+			if slices.Contains(config.Domains, r.Host) {
+				path, _ := website.CanonicalisePath(r.URL.Path)
+				newURL := config.BaseURL.JoinPath(path)
+				http.Redirect(w, r, newURL.String(), http.StatusMovedPermanently)
+			} else {
+				matches := re.FindSubmatchIndex([]byte(r.Host))
+				if matches == nil {
+					http.Redirect(w, r, config.BaseURL.String(), http.StatusTemporaryRedirect)
+
+					return
+				}
+				newHost := re.ExpandString([]byte{}, replace, r.Host, matches)
+				http.Redirect(w, r, string(newHost), http.StatusTemporaryRedirect)
+			}
 		})
 	} else {
 		loggingMux.Handle("/", mux)