Merge pull request #1914 from alphagov/reject-sms-senders-starting-with-00

Update SMS sender validation to reject senders starting with 00

app/main/forms.py

@@ -32,6 +32,7 @@ from wtforms.validators import DataRequired, Length, Optional, Regexp
 from app.main.validators import (
     Blacklist,
     CsvFileValidator,
+    DoesNotStartWithDoubleZero,
     LettersNumbersAndFullStopsOnly,
     NoCommasInPlaceHolders,
     OnlyGSMCharacters,
@@ -594,6 +595,7 @@ class ServiceSmsSenderForm(StripWhitespaceForm):
             Length(max=11, message="Enter 11 characters or fewer"),
             Length(min=3, message="Enter 3 characters or more"),
             LettersNumbersAndFullStopsOnly(),
+            DoesNotStartWithDoubleZero(),
         ]
     )
     is_default = BooleanField("Make this text message sender the default")

app/main/validators.py

@@ -92,3 +92,13 @@ class LettersNumbersAndFullStopsOnly:
     def __call__(self, form, field):
         if field.data and not re.match(self.regex, field.data):
             raise ValidationError(self.message)
+
+
+class DoesNotStartWithDoubleZero:
+
+    def __init__(self, message="Can't start with 00"):
+        self.message = message
+
+    def __call__(self, form, field):
+        if field.data and field.data.startswith("00"):
+            raise ValidationError(self.message)