mirror of
https://github.com/django/daphne.git
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106 lines
3.1 KiB
Python
106 lines
3.1 KiB
Python
from __future__ import unicode_literals
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import django
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from django.conf import settings
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from django.utils.module_loading import import_string
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from .routing import Router
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from .utils import name_that_thing
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class InvalidChannelLayerError(ValueError):
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pass
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class ChannelLayerManager(object):
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"""
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Takes a settings dictionary of backends and initialises them on request.
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"""
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def __init__(self):
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self.backends = {}
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@property
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def configs(self):
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# Lazy load settings so we can be imported
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return getattr(settings, "CHANNEL_LAYERS", {})
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def make_backend(self, name):
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# Load the backend class
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try:
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backend_class = import_string(self.configs[name]['BACKEND'])
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except KeyError:
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raise InvalidChannelLayerError("No BACKEND specified for %s" % name)
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except ImportError:
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raise InvalidChannelLayerError(
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"Cannot import BACKEND %r specified for %s" % (self.configs[name]['BACKEND'], name)
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)
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# Get routing
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try:
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routing = self.configs[name]['ROUTING']
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except KeyError:
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raise InvalidChannelLayerError("No ROUTING specified for %s" % name)
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# Initialise and pass config
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asgi_layer = backend_class(**self.configs[name].get("CONFIG", {}))
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return ChannelLayerWrapper(
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channel_layer=asgi_layer,
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alias=name,
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routing=routing,
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)
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def __getitem__(self, key):
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if key not in self.backends:
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self.backends[key] = self.make_backend(key)
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return self.backends[key]
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def __contains__(self, key):
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return key in self.configs
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def set(self, key, layer):
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"""
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Sets an alias to point to a new ChannelLayerWrapper instance, and
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returns the old one that it replaced. Useful for swapping out the
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backend during tests.
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"""
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old = self.backends.get(key, None)
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self.backends[key] = layer
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return old
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class ChannelLayerWrapper(object):
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"""
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Top level channel layer wrapper, which contains both the ASGI channel
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layer object as well as alias and routing information specific to Django.
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"""
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def __init__(self, channel_layer, alias, routing):
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self.channel_layer = channel_layer
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self.alias = alias
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self.routing = routing
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self.router = Router(self.routing)
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def __getattr__(self, name):
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return getattr(self.channel_layer, name)
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def __str__(self):
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return "%s (%s)" % (self.alias, name_that_thing(self.channel_layer))
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def local_only(self):
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# TODO: Can probably come up with a nicer check?
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return "inmemory" in self.channel_layer.__class__.__module__
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def get_channel_layer(alias="default"):
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"""
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Returns the raw ASGI channel layer for this project.
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"""
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if django.VERSION[1] > 9:
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django.setup(set_prefix=False)
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else:
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django.setup()
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return channel_layers[alias].channel_layer
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# Default global instance of the channel layer manager
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channel_layers = ChannelLayerManager()
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