76 lines
3.5 KiB
Python
76 lines
3.5 KiB
Python
import sys
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from ctypes.util import find_library
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from django.conf import settings
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from django.core.exceptions import ImproperlyConfigured
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from django.db.backends.sqlite3.base import (
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Database, DatabaseWrapper as SQLiteDatabaseWrapper, SQLiteCursorWrapper,
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)
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from django.utils import six
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from .client import SpatiaLiteClient
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from .features import DatabaseFeatures
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from .introspection import SpatiaLiteIntrospection
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from .operations import SpatiaLiteOperations
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from .schema import SpatialiteSchemaEditor
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class DatabaseWrapper(SQLiteDatabaseWrapper):
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SchemaEditorClass = SpatialiteSchemaEditor
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def __init__(self, *args, **kwargs):
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# Before we get too far, make sure pysqlite 2.5+ is installed.
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if Database.version_info < (2, 5, 0):
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raise ImproperlyConfigured('Only versions of pysqlite 2.5+ are '
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'compatible with SpatiaLite and GeoDjango.')
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# Trying to find the location of the SpatiaLite library.
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# Here we are figuring out the path to the SpatiaLite library
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# (`libspatialite`). If it's not in the system library path (e.g., it
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# cannot be found by `ctypes.util.find_library`), then it may be set
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# manually in the settings via the `SPATIALITE_LIBRARY_PATH` setting.
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self.spatialite_lib = getattr(settings, 'SPATIALITE_LIBRARY_PATH',
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find_library('spatialite'))
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if not self.spatialite_lib:
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raise ImproperlyConfigured('Unable to locate the SpatiaLite library. '
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'Make sure it is in your library path, or set '
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'SPATIALITE_LIBRARY_PATH in your settings.'
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)
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super(DatabaseWrapper, self).__init__(*args, **kwargs)
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self.features = DatabaseFeatures(self)
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self.ops = SpatiaLiteOperations(self)
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self.client = SpatiaLiteClient(self)
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self.introspection = SpatiaLiteIntrospection(self)
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def get_new_connection(self, conn_params):
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conn = super(DatabaseWrapper, self).get_new_connection(conn_params)
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# Enabling extension loading on the SQLite connection.
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try:
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conn.enable_load_extension(True)
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except AttributeError:
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raise ImproperlyConfigured(
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'The pysqlite library does not support C extension loading. '
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'Both SQLite and pysqlite must be configured to allow '
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'the loading of extensions to use SpatiaLite.')
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# Loading the SpatiaLite library extension on the connection, and returning
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# the created cursor.
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cur = conn.cursor(factory=SQLiteCursorWrapper)
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try:
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cur.execute("SELECT load_extension(%s)", (self.spatialite_lib,))
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except Exception as msg:
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new_msg = (
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'Unable to load the SpatiaLite library extension '
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'"%s" because: %s') % (self.spatialite_lib, msg)
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six.reraise(ImproperlyConfigured, ImproperlyConfigured(new_msg), sys.exc_info()[2])
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cur.close()
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return conn
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def prepare_database(self):
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super(DatabaseWrapper, self).prepare_database()
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# Check if spatial metadata have been initialized in the database
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with self.cursor() as cursor:
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cursor.execute("PRAGMA table_info(geometry_columns);")
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if cursor.fetchall() == []:
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arg = "1" if self.features.supports_initspatialmetadata_in_one_transaction else ""
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cursor.execute("SELECT InitSpatialMetaData(%s)" % arg)
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