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63 lines
2.6 KiB
63 lines
2.6 KiB
import os |
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from django.conf import settings |
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from django.core import signals |
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from django.core.exceptions import ImproperlyConfigured |
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from django.utils.functional import curry |
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__all__ = ('backend', 'connection', 'DatabaseError', 'IntegrityError') |
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if not settings.DATABASE_ENGINE: |
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settings.DATABASE_ENGINE = 'dummy' |
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try: |
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# Most of the time, the database backend will be one of the official |
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# backends that ships with Django, so look there first. |
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_import_path = 'django.db.backends.' |
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backend = __import__('%s%s.base' % (_import_path, settings.DATABASE_ENGINE), {}, {}, ['']) |
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except ImportError, e: |
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# If the import failed, we might be looking for a database backend |
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# distributed external to Django. So we'll try that next. |
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try: |
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_import_path = '' |
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backend = __import__('%s.base' % settings.DATABASE_ENGINE, {}, {}, ['']) |
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except ImportError, e_user: |
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# The database backend wasn't found. Display a helpful error message |
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# listing all possible (built-in) database backends. |
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backend_dir = os.path.join(__path__[0], 'backends') |
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try: |
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available_backends = [f for f in os.listdir(backend_dir) if not f.startswith('_') and not f.startswith('.') and not f.endswith('.py') and not f.endswith('.pyc')] |
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except EnvironmentError: |
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available_backends = [] |
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available_backends.sort() |
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if settings.DATABASE_ENGINE not in available_backends: |
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raise ImproperlyConfigured, "%r isn't an available database backend. Available options are: %s\nError was: %s" % \ |
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(settings.DATABASE_ENGINE, ", ".join(map(repr, available_backends)), e_user) |
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else: |
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raise # If there's some other error, this must be an error in Django itself. |
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# Convenient aliases for backend bits. |
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connection = backend.DatabaseWrapper(**settings.DATABASE_OPTIONS) |
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DatabaseError = backend.DatabaseError |
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IntegrityError = backend.IntegrityError |
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# Register an event that closes the database connection |
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# when a Django request is finished. |
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def close_connection(**kwargs): |
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connection.close() |
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signals.request_finished.connect(close_connection) |
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# Register an event that resets connection.queries |
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# when a Django request is started. |
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def reset_queries(**kwargs): |
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connection.queries = [] |
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signals.request_started.connect(reset_queries) |
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# Register an event that rolls back the connection |
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# when a Django request has an exception. |
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def _rollback_on_exception(**kwargs): |
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from django.db import transaction |
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try: |
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transaction.rollback_unless_managed() |
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except DatabaseError: |
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pass |
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signals.got_request_exception.connect(_rollback_on_exception)
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