django admin default filter values

admin.py

class YourAdmin(ModelAdmin):
    def changelist_view(self, request, extra_context=None):
        ref = request.META.get('HTTP_REFERER','')
        path = request.META.get('PATH_INFO','')
        if not ref.split(path)[-1].startswith('?'):
            q = request.GET.copy()
            q['usertype'] = 'Publisher'
            q['user_status__exact'] = 'activated'
            request.GET = q
            request.META['QUERY_STRING'] = request.GET.urlencode()
        return super(BulkMigrationAdmin,self).changelist_view(request, extra_context=extra_context)

I changed it slightly, so as not to hardcode in the parameters, and instead pass them in in the admin view:

class DefaultFilterMixIn(admin.ModelAdmin):
    def changelist_view(self, request, extra_context=None):
        ref = request.META.get('HTTP_REFERER', '')
        path = request.META.get('PATH_INFO', '')
        if not ref.split(path)[-1].startswith('?'):
            q = request.GET.copy()
            # use try/except in case default_filters isn't defined
            try:
                for filter in self.default_filters:
                    key = filter.split('=')[0]
                    value = filter.split('=')[1]
                    q[key] = value
                request.GET = q
            except:
                request.GET = q
            request.META['QUERY_STRING'] = request.GET.urlencode()
        return super(DefaultFilterMixIn, self).changelist_view(request, extra_context=extra_context)

class SomeAdmin(DefaultFilterMixIn):
    default_filters = ['o=2.1', 'open_job__exact=1']

This doesn't work. request.META.get('HTTP_REFERER', '') is page view behind. So the first time you try to change the filter value, you get the defaults again.

this maybe works better.
when following admin navigation, the filter will become effective.
when open the url directly, the filter will not work.

def changelist_view(self, request, extra_context=None):
ref = request.META.get('HTTP_REFERER', '').split('?')[0]
if ref and not ref.endswith(request.path):
...