from ctypes.util import find_library
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
from django.db.backends.sqlite3.base import *
from django.db.backends.sqlite3.base import DatabaseWrapper
_sqlite_extract, _sqlite_date_trunc, _sqlite_regexp
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
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 _cursor(self):
if self.connection is None:
## The following is the same as in django.db.backends.sqlite3.base ##
settings_dict = self.settings_dict
if not settings_dict['NAME']:
raise ImproperlyConfigured("Please fill out the database NAME in the settings module before using the database.")
kwargs = {
'database': settings_dict['NAME'],
'detect_types': Database.PARSE_DECLTYPES | Database.PARSE_COLNAMES,
}
kwargs.update(settings_dict['OPTIONS'])
self.connection = Database.connect(**kwargs)
# Register extract, date_trunc, and regexp functions.
self.connection.create_function("django_extract", 2, _sqlite_extract)
self.connection.create_function("django_date_trunc", 2, _sqlite_date_trunc)
self.connection.create_function("regexp", 2, _sqlite_regexp)
connection_created.send(sender=self.__class__)
## From here on, customized for GeoDjango ##
# Enabling extension loading on the SQLite connection.
try:
self.connection.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 = self.connection.cursor(factory=SQLiteCursorWrapper)
try:
cur.execute("SELECT load_extension(%s)", (self.spatialite_lib,))
except Exception, msg:
raise ImproperlyConfigured('Unable to load the SpatiaLite library extension '
'"%s" because: %s' % (self.spatialite_lib, msg))
return cur
else:
return self.connection.cursor(factory=SQLiteCursorWrapper)
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