How to set the current on the model instance using newforms admin.

from django.db import models
from django.http import Http404, HttpResponse, HttpResponseRedirect
from django.utils.html import escape
from django.utils.safestring import mark_safe
from django.db import models, transaction
from django.contrib.auth.models import User
from django.utils.encoding import force_unicode
from django.utils.translation import ugettext as _

class Post(models.Model):
    user = models.ForeignKey(User)
    content = models.TextField()

from django.contrib import admin

class PostModelAdmin(admin.ModelAdmin):

    fields= ('content',)

    def __call__(self, request, url):
        self.user = request.user
        return super(PostModelAdmin, self).__call__(request, url)

    def save_add(self, request, model, form, formsets, post_url_continue):
        """
        Saves the object in the "add" stage and returns an HttpResponseRedirect.

        `form` is a bound Form instance that's verified to be valid.
        """
        from django.contrib.admin.models import LogEntry, ADDITION
        from django.contrib.contenttypes.models import ContentType
        opts = model._meta
        new_object = form.save(commit=False)
        new_object.user = self.user
        new_object.save()
        form.save_m2m()

        if formsets:
            for formset in formsets:
                # HACK: it seems like the parent obejct should be passed into
                # a method of something, not just set as an attribute
                formset.instance = new_object
                formset.save()

        pk_value = new_object._get_pk_val()
        LogEntry.objects.log_action(request.user.id, ContentType.objects.get_for_model(model).id, pk_value, force_unicode(new_object), ADDITION)
        msg = _('The %(name)s "%(obj)s" was added successfully.') % {'name': opts.verbose_name, 'obj': new_object}
        # Here, we distinguish between different save types by checking for
        # the presence of keys in request.POST.
        if request.POST.has_key("_continue"):
            request.user.message_set.create(message=msg + ' ' + _("You may edit it again below."))
            if request.POST.has_key("_popup"):
                post_url_continue += "?_popup=1"
            return HttpResponseRedirect(post_url_continue % pk_value)
        if request.POST.has_key("_popup"):
            return HttpResponse('<script type="text/javascript">opener.dismissAddAnotherPopup(window, "%s", "%s");</script>' % \
                # escape() calls force_unicode.
                (escape(pk_value), escape(new_object)))
        elif request.POST.has_key("_addanother"):
            request.user.message_set.create(message=msg + ' ' + (_("You may add another %s below.") % opts.verbose_name))
            return HttpResponseRedirect(request.path)
        else:
            request.user.message_set.create(message=msg)
            # Figure out where to redirect. If the user has change permission,
            # redirect to the change-list page for this object. Otherwise,
            # redirect to the admin index.
            if self.has_change_permission(request, None):
                post_url = '../'
            else:
                post_url = '../../../'
            return HttpResponseRedirect(post_url)
    save_add = transaction.commit_on_success(save_add)

    def save_change(self, request, model, form, formsets=None):
        """
        Saves the object in the "change" stage and returns an HttpResponseRedirect.

        `form` is a bound Form instance that's verified to be valid.

        `formsets` is a sequence of InlineFormSet instances that are verified to be valid.
        """
        from django.contrib.admin.models import LogEntry, CHANGE
        from django.contrib.contenttypes.models import ContentType
        opts = model._meta
        new_object = form.save(commit=False)
        new_object.user = self.user
        new_object.save()
        form.save_m2m()
        pk_value = new_object._get_pk_val()

        if formsets:
            for formset in formsets:
                formset.save()

        # Construct the change message. TODO: Temporarily commented-out,
        # as manipulator object doesn't exist anymore, and we don't yet
        # have a way to get fields_added, fields_changed, fields_deleted.
        change_message = []
        #if manipulator.fields_added:
            #change_message.append(_('Added %s.') % get_text_list(manipulator.fields_added, _('and')))
        #if manipulator.fields_changed:
            #change_message.append(_('Changed %s.') % get_text_list(manipulator.fields_changed, _('and')))
        #if manipulator.fields_deleted:
            #change_message.append(_('Deleted %s.') % get_text_list(manipulator.fields_deleted, _('and')))
        #change_message = ' '.join(change_message)
        if not change_message:
            change_message = _('No fields changed.')
        LogEntry.objects.log_action(request.user.id, ContentType.objects.get_for_model(model).id, pk_value, force_unicode(new_object), CHANGE, change_message)

        msg = _('The %(name)s "%(obj)s" was changed successfully.') % {'name': opts.verbose_name, 'obj': new_object}
        if request.POST.has_key("_continue"):
            request.user.message_set.create(message=msg + ' ' + _("You may edit it again below."))
            if request.REQUEST.has_key('_popup'):
                return HttpResponseRedirect(request.path + "?_popup=1")
            else:
                return HttpResponseRedirect(request.path)
        elif request.POST.has_key("_saveasnew"):
            request.user.message_set.create(message=_('The %(name)s "%(obj)s" was added successfully. You may edit it again below.') % {'name': opts.verbose_name, 'obj': new_object})
            return HttpResponseRedirect("../%s/" % pk_value)
        elif request.POST.has_key("_addanother"):
            request.user.message_set.create(message=msg + ' ' + (_("You may add another %s below.") % opts.verbose_name))
            return HttpResponseRedirect("../add/")
        else:
            request.user.message_set.create(message=msg)
            return HttpResponseRedirect("../")
    save_change = transaction.commit_on_success(save_change)

admin.site.register(Post, PostModelAdmin)