48 lines
2.3 KiB
Python
48 lines
2.3 KiB
Python
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from django.db import connection, transaction
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class TransactionMiddleware(object):
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"""
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Transaction middleware. If this is enabled, each view function will be run
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with commit_on_response activated - that way a save() doesn't do a direct
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commit, the commit is done when a successful response is created. If an
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exception happens, the database is rolled back.
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"""
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def process_request(self, request):
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"""Enters transaction management"""
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transaction.enter_transaction_management()
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def process_exception(self, request, exception):
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"""Rolls back the database and leaves transaction management"""
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if transaction.is_dirty():
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# This rollback might fail because of network failure for example.
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# If rollback isn't possible it is impossible to clean the
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# connection's state. So leave the connection in dirty state and
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# let request_finished signal deal with cleaning the connection.
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transaction.rollback()
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transaction.leave_transaction_management()
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def process_response(self, request, response):
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"""Commits and leaves transaction management."""
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if not transaction.get_autocommit():
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if transaction.is_dirty():
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# Note: it is possible that the commit fails. If the reason is
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# closed connection or some similar reason, then there is
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# little hope to proceed nicely. However, in some cases (
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# deferred foreign key checks for exampl) it is still possible
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# to rollback().
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try:
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transaction.commit()
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except Exception:
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# If the rollback fails, the transaction state will be
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# messed up. It doesn't matter, the connection will be set
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# to clean state after the request finishes. And, we can't
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# clean the state here properly even if we wanted to, the
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# connection is in transaction but we can't rollback...
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transaction.rollback()
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transaction.leave_transaction_management()
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raise
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transaction.leave_transaction_management()
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return response
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