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102 lines
4.2 KiB
Python
102 lines
4.2 KiB
Python
import functools
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import hashlib
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from importlib import import_module
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from django.conf import settings
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from .handler import AsgiRequest
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def channel_session(func):
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"""
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Provides a session-like object called "channel_session" to consumers
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as a message attribute that will auto-persist across consumers with
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the same incoming "reply_channel" value.
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Use this to persist data across the lifetime of a connection.
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"""
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@functools.wraps(func)
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def inner(message, *args, **kwargs):
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# Make sure there's a reply_channel
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if not message.reply_channel:
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raise ValueError(
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"No reply_channel sent to consumer; @channel_session " +
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"can only be used on messages containing it."
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)
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# Make sure there's NOT a channel_session already
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if hasattr(message, "channel_session"):
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raise ValueError("channel_session decorator wrapped inside another channel_session decorator")
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# Turn the reply_channel into a valid session key length thing.
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# We take the last 24 bytes verbatim, as these are the random section,
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# and then hash the remaining ones onto the start, and add a prefix
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reply_name = message.reply_channel.name
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hashed = hashlib.md5(reply_name[:-24].encode()).hexdigest()[:8]
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session_key = "skt" + hashed + reply_name[-24:]
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# Make a session storage
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session_engine = import_module(settings.SESSION_ENGINE)
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session = session_engine.SessionStore(session_key=session_key)
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# If the session does not already exist, save to force our
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# session key to be valid.
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if not session.exists(session.session_key):
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session.save(must_create=True)
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message.channel_session = session
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# Run the consumer
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try:
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return func(message, *args, **kwargs)
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finally:
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# Persist session if needed
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if session.modified:
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session.save()
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return inner
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def http_session(func):
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"""
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Wraps a HTTP or WebSocket connect consumer (or any consumer of messages
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that provides a "cookies" or "get" attribute) to provide a "http_session"
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attribute that behaves like request.session; that is, it's hung off of
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a per-user session key that is saved in a cookie or passed as the
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"session_key" GET parameter.
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It won't automatically create and set a session cookie for users who
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don't have one - that's what SessionMiddleware is for, this is a simpler
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read-only version for more low-level code.
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If a message does not have a session we can inflate, the "session" attribute
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will be None, rather than an empty session you can write to.
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"""
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@functools.wraps(func)
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def inner(message, *args, **kwargs):
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try:
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# We want to parse the WebSocket (or similar HTTP-lite) message
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# to get cookies and GET, but we need to add in a few things that
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# might not have been there.
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if "method" not in message.content:
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message.content['method'] = "FAKE"
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request = AsgiRequest(message)
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except Exception as e:
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raise ValueError("Cannot parse HTTP message - are you sure this is a HTTP consumer? %s" % e)
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# Make sure there's NOT a http_session already
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if hasattr(message, "http_session"):
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raise ValueError("http_session decorator wrapped inside another http_session decorator")
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# Make sure there's a session key
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session_key = request.GET.get("session_key", None)
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if session_key is None:
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session_key = request.COOKIES.get(settings.SESSION_COOKIE_NAME, None)
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# Make a session storage
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if session_key:
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session_engine = import_module(settings.SESSION_ENGINE)
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session = session_engine.SessionStore(session_key=session_key)
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else:
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session = None
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message.http_session = session
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# Run the consumer
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result = func(message, *args, **kwargs)
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# Persist session if needed (won't be saved if error happens)
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if session is not None and session.modified:
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session.save()
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return result
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return inner
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