startTLS: making TLS support (and dependencies) optional

syncplay/client.py

@@ -1,6 +1,5 @@
 
 import ast
-import certifi
 import collections
 import hashlib
 import os
@@ -15,10 +14,16 @@ from functools import wraps
 
 from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
 from twisted.internet.protocol import ClientFactory
-from twisted.internet.ssl import Certificate, optionsForClientTLS
 from twisted.internet import reactor, task, defer, threads
 from twisted.application.internet import ClientService
 
+try:
+    import certifi
+    from twisted.internet.ssl import optionsForClientTLS
+    os.environ['SSL_CERT_FILE'] = certifi.where()
+except:
+    pass
+
 from syncplay import utils, constants, version
 from syncplay.constants import PRIVACY_SENDHASHED_MODE, PRIVACY_DONTSEND_MODE, \
     PRIVACY_HIDDENFILENAME
@@ -26,8 +31,6 @@ from syncplay.messages import getMissingStrings, getMessage
 from syncplay.protocols import SyncClientProtocol
 from syncplay.utils import isMacOS
 
-os.environ['SSL_CERT_FILE'] = certifi.where()
-
 
 class SyncClientFactory(ClientFactory):
     def __init__(self, client, retry=constants.RECONNECT_RETRIES):

syncplay/protocols.py

@@ -78,7 +78,7 @@ class SyncClientProtocol(JSONCommandProtocol):
             self.sendTLS({"startTLS": "send"})
             self._client.ui.showMessage("Attempting secure connection")
         else:
-            self._client.ui.showErrorMessage("This server does not support TLS")
+            self._client.ui.showErrorMessage("TLS is not supported")
             self.sendHello()
 
     def connectionLost(self, reason):

syncplay/server.py

@@ -5,12 +5,17 @@ import os
 import random
 import time
 from string import Template
-from OpenSSL import crypto
 
 from twisted.enterprise import adbapi
 from twisted.internet import task, reactor, ssl
 from twisted.internet.protocol import Factory
 
+try:
+    from OpenSSL import crypto
+    from twisted.internet import ssl
+except:
+    pass
+
 import syncplay
 from syncplay import constants
 from syncplay.messages import getMessage
@@ -212,7 +217,7 @@ class SyncFactory(Factory):
             self.options = contextFactory
         except Exception as e:
             print(e)
-            print("Cannot import certificates. TLS support not enabled.")
+            print("TLS support is not enabled.")
 
 
 class StatsRecorder(object):