# Copyright 2016 Egor Tensin <Egor.Tensin@gmail.com>
# This file is licensed under the terms of the MIT License.
# See LICENSE.txt for details.
from collections import Callable
import time
import vk.error
from vk.user import UserField
class StatusTracker:
DEFAULT_TIMEOUT = 5
def __init__(self, api, timeout=DEFAULT_TIMEOUT):
self._api = api
self._timeout = timeout
self._on_initial_status = []
self._on_status_update = []
self._on_connection_error = []
def _wait_after_connection_error(self):
time.sleep(self._timeout)
def add_database_writer(self, writer):
self.add_initial_status_handler(lambda user: writer.on_initial_status(user))
self.add_status_update_handler(lambda user: writer.on_status_update(user))
self.add_connection_error_handler(lambda e: writer.on_connection_error(e))
def add_initial_status_handler(self, fn):
self._assert_is_callback(fn)
self._on_initial_status.append(fn)
def add_status_update_handler(self, fn):
self._assert_is_callback(fn)
self._on_status_update.append(fn)
def add_connection_error_handler(self, fn):
self._assert_is_callback(fn)
self._on_connection_error.append(fn)
@staticmethod
def _assert_is_callback(fn):
if not isinstance(fn, Callable):
raise TypeError()
_USER_FIELDS = UserField.SCREEN_NAME, UserField.ONLINE, UserField.LAST_SEEN
def _query_status(self, uids):
return {user.get_uid(): user for user in self._api.users_get(uids, self._USER_FIELDS)}
def _notify_status(self, user):
for fn in self._on_initial_status:
fn(user)
def _notify_status_update(self, user):
for fn in self._on_status_update:
fn(user)
def _notify_connection_error(self, e):
for fn in self._on_connection_error:
fn(e)
def _query_initial_status(self, uids):
while True:
try:
return self._query_status(uids)
except vk.error.ConnectionError as e:
self._notify_connection_error(e)
self._wait_after_connection_error()
def _query_status_updates(self, uids):
while True:
self._wait_after_connection_error()
try:
return self._query_status(uids)
except vk.error.ConnectionError as e:
self._notify_connection_error(e)
@staticmethod
def _filter_status_updates(old_users, new_users):
for uid, user in new_users.items():
if old_users[uid].is_online() != user.is_online():
old_users[uid] = user
yield user
def _do_loop(self, uids):
users = self._query_initial_status(uids)
for user in users.values():
self._notify_status(user)
while True:
updated_users = self._query_status_updates(uids)
for user in self._filter_status_updates(users, updated_users):
self._notify_status_update(user)
def loop(self, uids):
try:
self._do_loop(uids)
except KeyboardInterrupt:
pass
