60 lines
2.2 KiB
Python
60 lines
2.2 KiB
Python
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from django.contrib.messages.storage.base import BaseStorage
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from django.contrib.messages.storage.cookie import CookieStorage
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from django.contrib.messages.storage.session import SessionStorage
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try:
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set
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except NameError:
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from sets import Set as set # Python 2.3
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class FallbackStorage(BaseStorage):
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"""
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Tries to store all messages in the first backend, storing any unstored
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messages in each subsequent backend backend.
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"""
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storage_classes = (CookieStorage, SessionStorage)
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def __init__(self, *args, **kwargs):
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super(FallbackStorage, self).__init__(*args, **kwargs)
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self.storages = [storage_class(*args, **kwargs)
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for storage_class in self.storage_classes]
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self._used_storages = set()
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def _get(self, *args, **kwargs):
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"""
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Gets a single list of messages from all storage backends.
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"""
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all_messages = []
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for storage in self.storages:
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messages, all_retrieved = storage._get()
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# If the backend hasn't been used, no more retrieval is necessary.
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if messages is None:
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break
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if messages:
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self._used_storages.add(storage)
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all_messages.extend(messages)
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# If this storage class contained all the messages, no further
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# retrieval is necessary
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if all_retrieved:
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break
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return all_messages, all_retrieved
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def _store(self, messages, response, *args, **kwargs):
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"""
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Stores the messages, returning any unstored messages after trying all
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backends.
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For each storage backend, any messages not stored are passed on to the
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next backend.
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"""
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for storage in self.storages:
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if messages:
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messages = storage._store(messages, response,
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remove_oldest=False)
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# Even if there are no more messages, continue iterating to ensure
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# storages which contained messages are flushed.
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elif storage in self._used_storages:
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storage._store([], response)
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self._used_storages.remove(storage)
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return messages
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