django-ddp/dddp/__init__.py

123 lines
3.3 KiB
Python

"""Django/PostgreSQL implementation of the Meteor DDP service."""
from __future__ import unicode_literals
import os.path
import sys
from pkg_resources import get_distribution, DistributionNotFound
from gevent.local import local
from dddp import alea
try:
_dist = get_distribution('django-ddp')
if not __file__.startswith(os.path.join(_dist.location, 'django-ddp', '')):
# not installed, but there is another version that *is*
raise DistributionNotFound
except DistributionNotFound:
__version__ = 'development'
else:
__version__ = _dist.version
default_app_config = 'dddp.apps.DjangoDDPConfig'
ADDED = 'added'
CHANGED = 'changed'
REMOVED = 'removed'
def greenify():
"""Patch threading and psycopg2 modules for green threads."""
if 'threading' in sys.modules:
raise Exception('threading module loaded before patching!')
from gevent.monkey import patch_all
patch_all()
from psycogreen.gevent import patch_psycopg
patch_psycopg()
class AlreadyRegistered(Exception):
"""Raised when registering over the top of an existing registration."""
pass
class ThreadLocal(local):
"""Thread local storage for greenlet state."""
_init_done = False
def __init__(self, **default_factories):
"""Create new thread storage instance."""
if self._init_done:
raise SystemError('__init__ called too many times')
self._init_done = True
self._default_factories = default_factories
def __getattr__(self, name):
"""Create missing attributes using default factories."""
try:
factory = self._default_factories[name]
except KeyError:
raise AttributeError(name)
obj = factory()
setattr(self, name, obj)
return obj
def get(self, name, factory, *factory_args, **factory_kwargs):
"""Get attribute, creating if required using specified factory."""
if not hasattr(self, name):
obj = factory(*factory_args, **factory_kwargs)
setattr(self, name, obj)
return obj
return getattr(self, name)
class RandomStreams(object):
def __init__(self):
self._streams = {}
self._seed = THREAD_LOCAL.alea_random.hex_string(20)
def get_seed(self):
return self._seed
def set_seed(self, val):
self._streams = {}
self._seed = val
random_seed = property(get_seed, set_seed)
def __getitem__(self, key):
if key not in self._streams:
return self._streams.setdefault(key, alea.Alea(self._seed, key))
return self._streams[key]
def serializer_factory():
"""Make a new DDP serializer."""
from django.core.serializers import get_serializer
return get_serializer('ddp')()
THREAD_LOCAL = ThreadLocal(
alea_random=alea.Alea,
random_streams=RandomStreams,
serializer=serializer_factory,
)
METEOR_ID_CHARS = u'23456789ABCDEFGHJKLMNPQRSTWXYZabcdefghijkmnopqrstuvwxyz'
def meteor_random_id(name=None):
if name is None:
stream = THREAD_LOCAL.alea_random
else:
stream = THREAD_LOCAL.random_streams[name]
return stream.random_string(17, METEOR_ID_CHARS)
def autodiscover():
from django.utils.module_loading import autodiscover_modules
from dddp.api import API
autodiscover_modules('ddp', register_to=API)
return API