Restrict new usernames

New users may only select usernames following this rules:
* min 3, max 16 characters
* starts with an letter and ends with an letter or number
* may only contain [a-zA-Z0-9_.]

fixes #494

accounts/forms.py

@@ -1,9 +1,58 @@
 from django import forms
+from django.core.validators import RegexValidator
 from django.utils.text import gettext_lazy as _
+
 from registration.forms import RegistrationFormUniqueEmail
 
+username_first_char_validator = RegexValidator(
+    r"^[a-zA-Z]", _("Username must start with a letter.")
+)
+username_validator = RegexValidator(
+    r"^[a-zA-Z0-9_.]*$",
+    _('Invalid username. Allowed characters are letters, numbers, "." and "_".'),
+)
+username_last_char_validator = RegexValidator(
+    r"[a-zA-Z0-9]$", _("Username must end with a letter or a number.")
+)
+no_consequtive_dots = RegexValidator(
+    r"\.\.",
+    _("Username must not contain consecutive . or _ characters."),
+    inverse_match=True,
+)
+no_consequtive_underscores = RegexValidator(
+    r"__",
+    _("Username must not contain consecutive . or _ characters."),
+    inverse_match=True,
+)
+no_consequtive_funnystuff = RegexValidator(
+    r"_\.",
+    _("Username must not contain consecutive . or _ characters."),
+    inverse_match=True,
+)
+no_consequtive_funnystuff2 = RegexValidator(
+    r"\._",
+    _("Username must not contain consecutive . or _ characters."),
+    inverse_match=True,
+)
+
 
 class RegistrationForm(RegistrationFormUniqueEmail):
+
+    username = forms.CharField(
+        max_length=16,
+        min_length=3,
+        strip=False,
+        validators=[
+            username_first_char_validator,
+            username_validator,
+            username_last_char_validator,
+            no_consequtive_dots,
+            no_consequtive_underscores,
+            no_consequtive_funnystuff,
+            no_consequtive_funnystuff2,
+        ],
+    )
+
     accept_privacy_policy = forms.BooleanField(
         required=True, initial=False, label=_("Accept privacy policy")
     )

locale/ar/LC_MESSAGES/django.po

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2022-03-15 17:56+0000\n"
 "Last-Translator: Christoph Meißner\n"
 "Language-Team: Arabic (http://www.transifex.com/coders4help/volunteer-planner/language/ar/)\n"
@@ -36,6 +36,18 @@ msgstr ""
 msgid "Accounts"
 msgstr "الحسابات "
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""
 

locale/bg/LC_MESSAGES/django.po

@@ -4,7 +4,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2022-03-15 17:56+0000\n"
 "Last-Translator: Christoph Meißner\n"
 "Language-Team: Bulgarian (http://www.transifex.com/coders4help/volunteer-planner/language/bg/)\n"
@@ -32,6 +32,18 @@ msgstr ""
 msgid "Accounts"
 msgstr ""
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""
 

locale/cs/LC_MESSAGES/django.po

@@ -6,7 +6,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2022-03-15 17:56+0000\n"
 "Last-Translator: Christoph Meißner\n"
 "Language-Team: Czech (http://www.transifex.com/coders4help/volunteer-planner/language/cs/)\n"
@@ -34,6 +34,18 @@ msgstr "poslední přihlášení"
 msgid "Accounts"
 msgstr "Účty"
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr "Přijmout zásady ochrany osobních údajů"
 

locale/da/LC_MESSAGES/django.po

@@ -5,7 +5,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2017-09-22 15:35+0000\n"
 "Last-Translator: Dorian Cantzen <[email protected]>\n"
 "Language-Team: Danish (http://www.transifex.com/coders4help/volunteer-planner/language/da/)\n"
@@ -33,6 +33,18 @@ msgstr ""
 msgid "Accounts"
 msgstr ""
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""
 

locale/de/LC_MESSAGES/django.po

@@ -19,7 +19,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2016-11-21 18:24+0000\n"
 "Last-Translator: Sönke Klinger <[email protected]>\n"
 "Language-Team: German (http://www.transifex.com/coders4help/volunteer-planner/language/de/)\n"
@@ -47,6 +47,18 @@ msgstr "Letzte Anmeldung"
 msgid "Accounts"
 msgstr "Benutzerkonten"
 
+msgid "Username must start with a letter."
+msgstr "Benutzername muss mit einem Buchstaben anfangen."
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr "Ungültiger Benutzername. Erlaubte Zeichen sind Buchstaben, Ziffern, \".\" and \".\"."
+
+msgid "Username must end with a letter or a number."
+msgstr "Benutzername muss mit einem Buchstaben oder einer Ziffer enden."
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr "Benutzername darf keine aufeinanderfolgenden . oder _ enthalten."
+
 msgid "Accept privacy policy"
 msgstr "Einwilligung (nach Art 6 Abs 1 Satz 1 a DSGVO)"
 

locale/el/LC_MESSAGES/django.po

@@ -9,7 +9,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2016-01-29 08:23+0000\n"
 "Last-Translator: Dorian Cantzen <[email protected]>\n"
 "Language-Team: Greek (http://www.transifex.com/coders4help/volunteer-planner/language/el/)\n"
@@ -37,6 +37,18 @@ msgstr ""
 msgid "Accounts"
 msgstr "Λογαριασμοί"
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""
 

locale/en/LC_MESSAGES/django.po

@@ -2,7 +2,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2015-10-04 21:53+0000\n"
 "Last-Translator: Dorian Cantzen <[email protected]>\n"
 "Language-Team: English (http://www.transifex.com/coders4help/volunteer-planner/language/en/)\n"
@@ -29,6 +29,18 @@ msgstr ""
 msgid "Accounts"
 msgstr ""
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""
 

locale/es/LC_MESSAGES/django.po

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2016-04-13 17:27+0000\n"
 "Last-Translator: Antonio Mireles <[email protected]>\n"
 "Language-Team: Spanish (http://www.transifex.com/coders4help/volunteer-planner/language/es/)\n"
@@ -36,6 +36,18 @@ msgstr ""
 msgid "Accounts"
 msgstr "Cuentas"
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""
 

locale/es_MX/LC_MESSAGES/django.po

@@ -4,7 +4,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2015-09-24 12:23+0000\n"
 "Last-Translator: Dorian Cantzen <[email protected]>\n"
 "Language-Team: Spanish (Mexico) (http://www.transifex.com/coders4help/volunteer-planner/language/es_MX/)\n"
@@ -32,6 +32,18 @@ msgstr ""
 msgid "Accounts"
 msgstr ""
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""
 

locale/fa/LC_MESSAGES/django.po

@@ -4,7 +4,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2016-01-29 08:23+0000\n"
 "Last-Translator: Dorian Cantzen <[email protected]>\n"
 "Language-Team: Persian (http://www.transifex.com/coders4help/volunteer-planner/language/fa/)\n"
@@ -32,6 +32,18 @@ msgstr ""
 msgid "Accounts"
 msgstr ""
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""
 

locale/fr/LC_MESSAGES/django.po

@@ -10,7 +10,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2016-12-08 20:50+0000\n"
 "Last-Translator: Dolfeus <[email protected]>\n"
 "Language-Team: French (http://www.transifex.com/coders4help/volunteer-planner/language/fr/)\n"
@@ -38,6 +38,18 @@ msgstr ""
 msgid "Accounts"
 msgstr "Comptes utilisateur"
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""
 

locale/hr/LC_MESSAGES/django.po

@@ -4,7 +4,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: volunteer-planner.org\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2022-03-25 11:54+0100\n"
+"POT-Creation-Date: 2022-03-25 21:54+0100\n"
 "PO-Revision-Date: 2016-01-29 08:23+0000\n"
 "Last-Translator: Dorian Cantzen <[email protected]>\n"
 "Language-Team: Croatian (http://www.transifex.com/coders4help/volunteer-planner/language/hr/)\n"
@@ -32,6 +32,18 @@ msgstr ""
 msgid "Accounts"
 msgstr ""
 
+msgid "Username must start with a letter."
+msgstr ""
+
+msgid "Invalid username. Allowed characters are letters, numbers, \".\" and \"_\"."
+msgstr ""
+
+msgid "Username must end with a letter or a number."
+msgstr ""
+
+msgid "Username must not contain consecutive . or _ characters."
+msgstr ""
+
 msgid "Accept privacy policy"
 msgstr ""