Ability to override via query parameter and persist for session?

[truthdoug]

A pattern we've used (with internal code, not django-flags):

• have a site-wide feature flag, either in django settings or (more commonly) in django-constance
• middleware or hook that detects query parameters that explicitly choose one state or the other. For example, if the feature is called newfeature then ?newfeature would always enable it and ?no-newfeature would disable it
• the middleware also stores the overriden value in the django user session

With this the priority of choosing the feature or not is:

1. query parameter - if it exists on the current request, that trumps all (and is set on the session)
2. django session value - if the feature is explicitly set or unset in the session, use that
3. global value - otherwise use the site-wide setting

I'm newly finding out about django-flags and I've read through examples in the documentation but don't readily see a way to implement this overriding behavior. Is there a way to do this? Perhaps with a combination of conditions for the feature?

[harshavardhanreddy06]

Does this repo part of Gsoc 2026?

[truthdoug]

@harshavardhanreddy06 I don't think commenting on an unrelated issue will provide you the information you want. I am not an owner or administrator of this project

[willbarton]

I'm newly finding out about django-flags and I've read through examples in the documentation but don't readily see a way to implement this overriding behavior. Is there a way to do this? Perhaps with a combination of conditions for the feature?

Hi @truthdoug I'm sorry I didn't see this before now.

I think you could achieve something like this with a custom condition that stored the query string

This is some pseudocode off top of my head, so it may be wrong/incomplete/etc, but using the parameter condition as a starting point, you could create a condition that checks either parameter or session, and if parameter is set, store it in the Django session:

# the validator will have to be written
@register("session parameter", validator=validate_session_parameter)
def parameter_condition(param_name, request=None, **kwargs):
    if request is None:
        # will need request for both session and parameter lookup
        raise RequiredForCondition(
            "request is required for condition 'parameter'"
        )

    try:
        param_name, param_value = param_name.split("=")
    except ValueError:
        param_value = "True"

    if request.GET.get(param_name) == param_value:
        # Store in the session
        request.session[param_name] = True
    
    # Return the session check?
    return request.session.get(param_name, False)

[willbarton]

@harshavardhanreddy06 no.