server: new options to disable certain IP versions

On some setups, IPv6 or IPv4 might be disabled in the OS.
In my case IPv6 is disabled and this causes errors when starting the server.

syncplay/ep_server.py

@@ -6,19 +6,26 @@
 
 from syncplay.server import SyncFactory, ConfigurationGetter
 
-class ServerStatus: pass
+
+class ServerStatus:
+    listening6 = False
+    listening4 = False
+
 
 def isListening6(f):
     ServerStatus.listening6 = True
 
+
 def isListening4(f):
     ServerStatus.listening4 = True
 
+
 def failed6(f):
     ServerStatus.listening6 = False
     print(f.value)
     print("IPv6 listening failed.")
 
+
 def failed4(f):
     ServerStatus.listening4 = False
     if f.type is CannotListenError and ServerStatus.listening6:
@@ -27,6 +34,7 @@ def failed4(f):
         print(f.value)
         print("IPv4 listening failed.")
 
+
 def main():
     argsGetter = ConfigurationGetter()
     args = argsGetter.getConfiguration()
@@ -45,15 +53,18 @@ def main():
         args.stats_db_file,
         args.tls
     )
-    endpoint6 = TCP6ServerEndpoint(reactor, int(args.port))
-    endpoint6.listen(factory).addCallbacks(isListening6, failed6)
-    endpoint4 = TCP4ServerEndpoint(reactor, int(args.port))
-    endpoint4.listen(factory).addCallbacks(isListening4, failed4)
+    if args.disable_ipv6 is False:
+        endpoint6 = TCP6ServerEndpoint(reactor, int(args.port))
+        endpoint6.listen(factory).addCallbacks(isListening6, failed6)
+    if args.disable_ipv4 is False:
+        endpoint4 = TCP4ServerEndpoint(reactor, int(args.port))
+        endpoint4.listen(factory).addCallbacks(isListening4, failed4)
     if ServerStatus.listening6 or ServerStatus.listening4:
         reactor.run()
     else:
         print("Unable to listen using either IPv4 and IPv6 protocols. Quitting the server now.")
         sys.exit()
 
+
 if __name__ == "__main__":
-    main()
+    main()

syncplay/messages_de.py

@@ -499,6 +499,8 @@
     "server-startTLS-argument": "Erlaube TLS-Verbindungen mit den Zertifikatdateien im Angegebenen Pfad",
     "server-messed-up-motd-unescaped-placeholders": "Die Nachricht des Tages hat unmaskierte Platzhalter. Alle $-Zeichen sollten verdoppelt werden ($$).",
     "server-messed-up-motd-too-long": "Die Nachricht des Tages ist zu lang - Maximal {} Zeichen, aktuell {}.",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Unbekannter Befehl {}",  # message

syncplay/messages_en.py

@@ -500,6 +500,8 @@
     "server-startTLS-argument": "Enable TLS connections using the certificate files in the path provided",
     "server-messed-up-motd-unescaped-placeholders": "Message of the Day has unescaped placeholders. All $ signs should be doubled ($$).",
     "server-messed-up-motd-too-long": "Message of the Day is too long - maximum of {} chars, {} given.",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Unknown command {}",  # message

syncplay/messages_eo.py

@@ -503,6 +503,8 @@
     "server-startTLS-argument": "Ŝalti TLS-konektojn per la atestilaj dosieroj en la donita vojo",
     "server-messed-up-motd-unescaped-placeholders": "Mesaĝo de tago havas neŝirmitajn anstataŭiĝojn. Ĉiuj dolarsignoj devus aperi duoble ($$).",
     "server-messed-up-motd-too-long": "Mesaĝo de tago estas tro longa – maksimuma kvanto estas {} signoj, sed {} estas donitaj.",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Nekonata ordono {}",  # message

syncplay/messages_es.py

@@ -499,6 +499,8 @@
     "server-startTLS-argument": "Habilitar conexiones TLS usando los archivos de certificado en la ruta provista",
     "server-messed-up-motd-unescaped-placeholders": "El mensaje del dia contiene marcadores de posición sin escapar. Todos los signos $ deberían ser dobles ($$).",
     "server-messed-up-motd-too-long": "El mensaje del día es muy largo - máximo de {} caracteres, se recibieron {}.",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Comando desconocido {}",  # message

syncplay/messages_fr.py

@@ -500,6 +500,8 @@
     "server-startTLS-argument": "Activer les connexions TLS à l'aide des fichiers de certificat dans le chemin fourni",
     "server-messed-up-motd-unescaped-placeholders": "Le message du jour a des espaces réservés non échappés. Tous les signes $ doivent être doublés ($$).",
     "server-messed-up-motd-too-long": "Le message du jour est trop long: {}caractères maximum, {} donnés.",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Commande inconnue {}",  # message

syncplay/messages_it.py

@@ -499,6 +499,8 @@
     "server-startTLS-argument": "Abilita il protocollo TLS usando i certificati contenuti nel percorso indicato",
     "server-messed-up-motd-unescaped-placeholders": "Il messaggio del giorno ha dei caratteri non 'escaped'. Tutti i simboli $ devono essere doppi ($$).",
     "server-messed-up-motd-too-long": "Il messaggio del giorno è troppo lungo - numero massimo di caratteri è {}, {} trovati.",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Comando non riconosciuto {}",  # message

syncplay/messages_pt_BR.py

@@ -500,6 +500,8 @@
     "server-startTLS-argument": "Habilita conexões TLS usando os arquivos de certificado no caminho fornecido",
     "server-messed-up-motd-unescaped-placeholders": "A Mensagem do Dia possui placeholders não escapados. Todos os sinais de $ devem ser dobrados (como em $$).",
     "server-messed-up-motd-too-long": "A Mensagem do Dia é muito longa - máximo de {} caracteres, {} foram dados.",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Comando desconhecido: {}",  # message

syncplay/messages_pt_PT.py

@@ -499,6 +499,8 @@
     "server-startTLS-argument": "Habilita conexões TLS usando os arquivos de certificado no caminho fornecido",
     "server-messed-up-motd-unescaped-placeholders": "A Mensagem do Dia possui placeholders não escapados. Todos os sinais de $ devem ser dobrados (como em $$).",
     "server-messed-up-motd-too-long": "A Mensagem do Dia é muito longa - máximo de {} caracteres, {} foram dados.",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Comando desconhecido: {}",  # message

syncplay/messages_ru.py

@@ -496,6 +496,8 @@
     "server-startTLS-argument": "Включить TLS-соединения используя файлы сертификатов в указанном пути",
     "server-messed-up-motd-unescaped-placeholders": "MOTD-сообщение содержит неэкранированные спецсимволы. Все знаки $ должны быть продублированы ($$).",
     "server-messed-up-motd-too-long": "MOTD-сообщение слишком длинное: максимальная длина - {} символ(ов), текущая длина - {} символ(ов).",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Неизвестная команда: {}",  # message

syncplay/messages_tr.py

@@ -500,6 +500,8 @@
     "server-startTLS-argument": "Dosya yolundaki sertifika dosyalarını kullanarak TLS bağlantılarını etkinleştirin",
     "server-messed-up-motd-unescaped-placeholders": "Günün Mesajında çıkış karaktersiz yer tutucular var. Tüm $ işaretleri iki katına çıkarılmalıdır ($$).",
     "server-messed-up-motd-too-long": "Günün Mesajı çok uzun - maksimum {} karakter olmalı, {} verildi.",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "Bilinmeyen komut {}",  # message

syncplay/messages_zh_CN.py

@@ -500,6 +500,8 @@
     "server-startTLS-argument": "使用提供的路径中的证书文件启用TLS连接",
     "server-messed-up-motd-unescaped-placeholders": "每日信息中有未转义的占位符。所有 $ 字符应当重复两遍 ($$).",
     "server-messed-up-motd-too-long": "每日信息过长 - 最大{}个chars, 给出的长度{}",
+    "server-do-not-listen-on-ipv4": "Don't listen on IPv4 when starting the server.",
+    "server-do-not-listen-on-ipv6": "Don't listen on IPv6 when starting the server.",
 
     # Server errors
     "unknown-command-server-error": "未知命令 {}",  # message

syncplay/server.py

@@ -290,18 +290,18 @@ class StatsRecorder(object):
     def __init__(self, dbHandle, roomManager):
         self._dbHandle = dbHandle
         self._roomManagerHandle = roomManager
-        
+
     def startRecorder(self, delay):
         try:
             self._dbHandle.connect()
             reactor.callLater(delay, self._scheduleClientSnapshot)
         except:
             print("--- Error in initializing the stats database. Server Stats not enabled. ---")
-    
+
     def _scheduleClientSnapshot(self):
         self._clientSnapshotTimer = task.LoopingCall(self._runClientSnapshot)
-        self._clientSnapshotTimer.start(constants.SERVER_STATS_SNAPSHOT_INTERVAL)    
-    
+        self._clientSnapshotTimer.start(constants.SERVER_STATS_SNAPSHOT_INTERVAL)
+
     def _runClientSnapshot(self):
         try:
             snapshotTime = int(time.time())
@@ -497,7 +497,7 @@ def findFreeUsername(self, username, maxUsernameLength=constants.MAX_USERNAME_LE
         while username.lower() in allnames:
             username += '_'
         return username
-    
+
     def exportRooms(self):
         return self._rooms
 
@@ -889,3 +889,5 @@ def _prepareArgParser(self):
         self._argparser.add_argument('--max-username-length', metavar='maxUsernameLength', type=int, nargs='?', help=getMessage("server-maxusernamelength-argument").format(constants.MAX_USERNAME_LENGTH))
         self._argparser.add_argument('--stats-db-file', metavar='file', type=str, nargs='?', help=getMessage("server-stats-db-file-argument"))
         self._argparser.add_argument('--tls', metavar='path', type=str, nargs='?', help=getMessage("server-startTLS-argument"))
+        self._argparser.add_argument('--disable-ipv4', action='store_true', help=getMessage("server-do-not-listen-on-ipv4"))
+        self._argparser.add_argument('--disable-ipv6', action='store_true', help=getMessage("server-do-not-listen-on-ipv6"))