#20784: RegexValidator should accept a new parameter to perform reversed
validation
------------------------------+----------------------------
Reporter: devfeng | Owner: nobody
Type: New feature | Status: new
Component: Core (Other) | Version: master
Severity: Normal | Keywords: RegexValidator
Triage Stage: Unreviewed | Has patch: 1
Easy pickings: 0 | UI/UX: 0
------------------------------+----------------------------
In current implementation, RegexValidator only raises ValidationError when
pattern DOES NOT match regex, while it is pretty common to use a
"reversed" RegexValidator that raises ValidationError when pattern MATCHES
regex. A typical scenario is to catch potential XSS inputs in form field
validation (if it matches then the validator should panic).
Technically such reversed match could be performed by tweaking the regex
itself, however in real world, not everybody is a regex master and there
are a lot of people who may prefer a more straightforward solution as
simple as "not some_condition".
In my own projects, I've written a ReversedRegexValidator by subclassing
RegexValidator and overriding the __call__() method to change it's
behavior (basically it just copied everything and then removed the "not"
statement). It worked well, however there are some problems:
1. RegexValidator uses some Django internal utils that are not documented
during upgrades. For example, in Django 1.4.x, RegexValidator used
smart_unicode() from utils.encoding, while in Django 1.5.x, it changed to
force_text(). The custom ReversedRegexValidator will need to be upgraded
as well for such internal change.
2. Overriding the whole __call__() method in order to just remove (or
have) a "not" operation seems to be too much. But that's the current
problem with RegexValidator.
So my suggestion is to add a new parameter, say "reverse", to
RegexValidator. By default it's False and won't change anything to
existing codes, but a user can very easily change it's matching behavior
by passing reverse=True.
I've had my changes ready for review. Test cases have been updated as
well.
--
Ticket URL: <https://code.djangoproject.com/ticket/20784>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to django-updates+unsubscr...@googlegroups.com.
To post to this group, send email to django-updates@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/050.63ec669a2c3e45aec5143ad14ab10724%40djangoproject.com.
For more options, visit https://groups.google.com/groups/opt_out.
