Allow disabling welcome messages (--welcome)

Add the --welcome option, that takes an on/off parameter and
enables/disables welcome messages when a new user joins the MUC.
The default is enabled.

send_welcome() was refactored from muc_online().

Issue: RoboTux's rant.

README.md

@@ -37,7 +37,7 @@ Usage
 
 ```
 usage: kaabot [-h] [-d] [-b DATABASE] [-j JID] [-p PASSWORD] [-m MUC]
-              [-n NICK] [-V VOCABULARY_FILE]
+              [-n NICK] [-V VOCABULARY_FILE] [--welcome WELCOME]
 
 optional arguments:
   -h, --help            show this help message and exit
@@ -53,6 +53,7 @@ optional arguments:
   -n NICK, --nick NICK  nickname to use in the chatroom (default: KaaBot)
   -V VOCABULARY_FILE, --vocabulary_file VOCABULARY_FILE
                         path to an alternative vocabulary file
+  --welcome WELCOME     welcome users joining the MUC (on/off, default: on)
 ```
 
 License

kaabot.py

@@ -52,7 +52,8 @@ default_vocabulary = {
 
 
 class KaaBot(sleekxmpp.ClientXMPP):
-    def __init__(self, jid, password, database, muc, nick, vocabulary_file):
+    def __init__(self, jid, password, database, muc, nick, vocabulary_file,
+                 welcome):
         sleekxmpp.ClientXMPP.__init__(self, jid, password)
 
         self.muc = muc
@@ -65,6 +66,8 @@ class KaaBot(sleekxmpp.ClientXMPP):
 
         self.vocabulary = self.init_vocabulary(vocabulary_file)
 
+        self.welcome = welcome
+
         self.users = self.db['user']
         # Initialize table with correct type.
         self.users.create_column('nick', sqlalchemy.String)
@@ -319,6 +322,12 @@ class KaaBot(sleekxmpp.ClientXMPP):
                           mbody=insult,
                           mtype='groupchat')
 
+    def send_welcome(self, nick, dest, date):
+        msg = self.pick_sentence('welcome').format(nick=nick, date=date)
+        self.send_message(mto=dest,
+                          mbody=msg,
+                          mtype='groupchat')
+
     def pick_sentence(self, type):
         """Returns a random sentence picked in the loaded vocabulary.
 
@@ -351,11 +360,12 @@ class KaaBot(sleekxmpp.ClientXMPP):
                         offline_timestamp = user['offline_timestamp']
                         date = datetime.datetime.strftime(offline_timestamp,
                                                           format="%c")
-                        msg = self.pick_sentence('welcome').format(nick=nick,
-                                                                   date=date)
-                        self.send_message(mto=presence['from'].bare,
-                                          mbody=msg,
-                                          mtype='groupchat')
+                        logging.debug('KaaBot : user {} connected, last seen {}'
+                                      .format(nick, date))
+                        if self.welcome:
+                            dest = presence['from'].bare
+                            self.send_welcome(nick, dest, date)
+
                     except TypeError:
                         msg = 'KaaBot : No offline timestamp yet for {nick}'
                         logging.debug(msg.format(nick=nick))
@@ -379,6 +389,19 @@ class KaaBot(sleekxmpp.ClientXMPP):
                               ['nick'])
 
 
+def str_to_bool(text):
+    """Converts a string to a boolean.
+
+    Raises an exception if the string does not describe a boolean value.
+    """
+    text = text.lower()
+    if text in ["on", "true", "1"]:
+        return True
+    elif text in ["off", "false", "0"]:
+        return False
+    raise TypeError
+
+
 if __name__ == '__main__':
 
     config_dir = xdg.BaseDirectory.save_config_path("kaabot")
@@ -403,6 +426,9 @@ if __name__ == '__main__':
                       help="nickname to use in the chatroom (default: KaaBot)")
     argp.add_argument("-V", "--vocabulary_file", dest="vocabulary_file",
                       help="path to an alternative vocabulary file")
+    argp.add_argument("--welcome", dest="welcome", default="on",
+                      type=str_to_bool,
+                      help="welcome users joining the MUC (on/off, default: on)")
 
     args = argp.parse_args()
 
@@ -427,7 +453,8 @@ if __name__ == '__main__':
         logging.debug('Config file exists.')
 
     bot = KaaBot(args.jid, args.password, args.database,
-                 args.muc, args.nick, args.vocabulary_file)
+                 args.muc, args.nick, args.vocabulary_file,
+                 args.welcome)
     bot.register_plugin('xep_0045')
     bot.register_plugin('xep_0071')
     bot.register_plugin('xep_0172')