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import sys
from ctypes.util import find_library
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
from django.db.backends.sqlite3.base import (Database,
DatabaseWrapper as SQLiteDatabaseWrapper, SQLiteCursorWrapper)
from django.contrib.gis.db.backends.spatialite.client import SpatiaLiteClient
from django.contrib.gis.db.backends.spatialite.creation import SpatiaLiteCreation
from django.contrib.gis.db.backends.spatialite.introspection import SpatiaLiteIntrospection
from django.contrib.gis.db.backends.spatialite.operations import SpatiaLiteOperations
from django.contrib.gis.db.backends.spatialite.schema import SpatialiteSchemaEditor
from django.utils import six
class DatabaseWrapper(SQLiteDatabaseWrapper):
def __init__(self, *args, **kwargs):
# Before we get too far, make sure pysqlite 2.5+ is installed.
if Database.version_info < (2, 5, 0):
raise ImproperlyConfigured('Only versions of pysqlite 2.5+ are '
'compatible with SpatiaLite and GeoDjango.')
# Trying to find the location of the SpatiaLite library.
# Here we are figuring out the path to the SpatiaLite library
# (`libspatialite`). If it's not in the system library path (e.g., it
# cannot be found by `ctypes.util.find_library`), then it may be set
# manually in the settings via the `SPATIALITE_LIBRARY_PATH` setting.
self.spatialite_lib = getattr(settings, 'SPATIALITE_LIBRARY_PATH',
find_library('spatialite'))
if not self.spatialite_lib:
raise ImproperlyConfigured('Unable to locate the SpatiaLite library. '
'Make sure it is in your library path, or set '
'SPATIALITE_LIBRARY_PATH in your settings.'
)
super(DatabaseWrapper, self).__init__(*args, **kwargs)
self.ops = SpatiaLiteOperations(self)
self.client = SpatiaLiteClient(self)
self.creation = SpatiaLiteCreation(self)
self.introspection = SpatiaLiteIntrospection(self)
def schema_editor(self, *args, **kwargs):
"Returns a new instance of this backend's SchemaEditor"
return SpatialiteSchemaEditor(self, *args, **kwargs)
def get_new_connection(self, conn_params):
conn = super(DatabaseWrapper, self).get_new_connection(conn_params)
# Enabling extension loading on the SQLite connection.
try:
conn.enable_load_extension(True)
except AttributeError:
raise ImproperlyConfigured(
'The pysqlite library does not support C extension loading. '
'Both SQLite and pysqlite must be configured to allow '
'the loading of extensions to use SpatiaLite.')
# Loading the SpatiaLite library extension on the connection, and returning
# the created cursor.
cur = conn.cursor(factory=SQLiteCursorWrapper)
try:
cur.execute("SELECT load_extension(%s)", (self.spatialite_lib,))
except Exception as msg:
new_msg = (
'Unable to load the SpatiaLite library extension '
'"%s" because: %s') % (self.spatialite_lib, msg)
six.reraise(ImproperlyConfigured, ImproperlyConfigured(new_msg), sys.exc_info()[2])
cur.close()
return conn
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