Listen on custom address (#140)

Co-Authored-By: eternal-flame-AD <ef@eternalflame.info>

config.example.yml

@@ -2,11 +2,13 @@
 # Save it to `config.yml` when edited
 
 server:
+  listenaddr: "" # the address to bind on, leave empty to bind on all addresses
   port: 80 # the port the HTTP server will listen on
 
   ssl:
     enabled: false # if https should be enabled
     redirecttohttps: true # redirect to https if site is accessed by http
+    listenaddr: "" # the address to bind on, leave empty to bind on all addresses
     port: 443 # the https port
     certfile: # the cert file (leave empty when using letsencrypt)
     certkey: # the cert key (leave empty when using letsencrypt)

config/config.go

@@ -10,10 +10,12 @@ import (
 // Configuration is stuff that can be configured externally per env variables or config file (config.yml).
 type Configuration struct {
 	Server struct {
-		Port int `default:"80"`
-		SSL  struct {
+		ListenAddr string `default:""`
+		Port       int    `default:"80"`
+		SSL        struct {
 			Enabled         *bool  `default:"false"`
 			RedirectToHTTPS *bool  `default:"true"`
+			ListenAddr      string `default:""`
 			Port            int    `default:"443"`
 			CertFile        string `default:""`
 			CertKey         string `default:""`

runner/runner.go

@@ -21,8 +21,9 @@ func Run(engine *gin.Engine, conf *config.Configuration) {
 			httpHandler = redirectToHTTPS(string(conf.Server.SSL.Port))
 		}
 
+		addr := fmt.Sprintf("%s:%d", conf.Server.SSL.ListenAddr, conf.Server.SSL.Port)
 		s := &http.Server{
-			Addr:    fmt.Sprintf(":%d", conf.Server.SSL.Port),
+			Addr:    addr,
 			Handler: engine,
 		}
 
@@ -35,13 +36,14 @@ func Run(engine *gin.Engine, conf *config.Configuration) {
 			httpHandler = certManager.HTTPHandler(httpHandler)
 			s.TLSConfig = &tls.Config{GetCertificate: certManager.GetCertificate}
 		}
-		fmt.Println("Started Listening on port", conf.Server.SSL.Port)
+		fmt.Println("Started Listening for TLS connection on " + addr)
 		go func() {
 			log.Fatal(s.ListenAndServeTLS(conf.Server.SSL.CertFile, conf.Server.SSL.CertKey))
 		}()
 	}
-	fmt.Println("Started Listening on port", conf.Server.Port)
-	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", conf.Server.Port), httpHandler))
+	addr := fmt.Sprintf("%s:%d", conf.Server.ListenAddr, conf.Server.Port)
+	fmt.Println("Started Listening for plain HTTP connection on " + addr)
+	log.Fatal(http.ListenAndServe(addr, httpHandler))
 }
 
 func redirectToHTTPS(port string) http.HandlerFunc {