Handle unicodes in username + limit username length

dynamicweb/settings/base.py

@@ -761,6 +761,7 @@ OTP_VERIFY_ENDPOINT = env('OTP_VERIFY_ENDPOINT')
 FIRST_VM_ID_AFTER_EU_VAT = int_env('FIRST_VM_ID_AFTER_EU_VAT')
 PRE_EU_VAT_RATE = float(env('PRE_EU_VAT_RATE'))
 
+MAX_USERNAME_LENGTH = int_env('MAX_USERNAME_LENGTH', 18)
 
 if DEBUG:
     from .local import *  # flake8: noqa

membership/models.py

@@ -77,28 +77,54 @@ def get_first_and_last_name(full_name):
     return first_name, last_name
 
 
+def limit_username_length(username):
+    """
+    Limit the length of username before the addition of random numbers to
+    18 characters
+
+    :param username: the username to limit
+    :return:
+    """
+    if len(username) > settings.MAX_USERNAME_LENGTH:
+        username = username[(len(username) - settings.MAX_USERNAME_LENGTH):]
+    return username.strip()
+
+
 def assign_username(user):
     if not user.username:
         ldap_manager = LdapManager()
 
         # Try to come up with a username
         first_name, last_name = get_first_and_last_name(user.name)
-        user.username = unicodedata.normalize('NFKD', first_name + last_name)
+        user.username = unicodedata.normalize('NFKD', first_name + last_name).encode('ascii', 'ignore')
         user.username = "".join([char for char in user.username if char.isalnum()]).lower()
+        if user.username.strip() == "":
+            try:
+                # the inferred username from name is empty, hence attempt
+                # inferring a username from email
+                logger.debug("Inferred username from name is empty. So, "
+                             "inferring from email now.")
+                user.username = user.email[0:user.email.index("@")]
+            except Exception as ex:
+                logger.debug("Exception %s" % str(ex))
+                user.username = get_random_string(
+                    allowed_chars='abcdefghijklmnopqrstuvwxyz'
+                )
         exist = True
+        user_username = limit_username_length(user.username)
         while exist:
             # Check if it exists
-            exist, entries = ldap_manager.check_user_exists(user.username)
+            exist, entries = ldap_manager.check_user_exists(user_username)
             if exist:
                 # If username exists in ldap, come up with a new user name and check it again
-                user.username = user.username + str(random.randint(0, 2 ** 10))
+                user.username = user_username + str(random.randint(0, 2 ** 10))
             else:
                 # If username does not exists in ldap, try to save it in database
                 try:
                     user.save()
                 except IntegrityError:
                     # If username exists in database then come up with a new username
-                    user.username = user.username + str(random.randint(0, 2 ** 10))
+                    user.username = user_username + str(random.randint(0, 2 ** 10))
                     exist = True