def get_keys(model, key):
    cache_key = "%s-%s-list" % (model._meta.module_name, key)
    result = cache.get(cache_key)
    if not result:
        result = frozenset(int(row[0]) for row in model.objects.distinct().values_list(key))
        cache.set(cache_key, result)
    return result

def weapon_top(request, weapon_id=None):
    ctx = {}
    if not weapon_id:
        ctx['weapons'] = weapons = cache.get('top-weapon-list')
        if not weapons:
            records = ( InfoWeapon.objects.filter(weapon_id=weapon_id)\
                            .select_related(depth=1).order_by('-kills')[0]
                        for weapon_id in get_keys(InfoWeapon, 'weapon_id'))

            ctx['weapons'] = stats = sorted(({'id':record.weapon_id, 'weapon':record.get_name(),
                                              'kills':record.kills, 'player': record.player}
                                             for record in records), key=itemgetter('kills'), reverse=True)

            cache.set('top-weapon-list', stats, CACHE_TIME)
    else:
        ctx['players'] = players = InfoWeapon.objects\
            .filter(weapon_id=weapon_id).order_by('-kills').select_related(depth=1)[:50]
        ctx['name'] = players[0].get_name()

    return render_to_response('players/boards/weapon_list.html', ctx, RequestContext(request))