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import logging
import os
import re
from ctypes import CDLL, CFUNCTYPE, c_char_p, c_int
from ctypes.util import find_library
from django.contrib.gis.gdal.error import GDALException
from django.core.exceptions import ImproperlyConfigured
logger = logging.getLogger('django.contrib.gis')
# Custom library path set?
from django.conf import settings
lib_path = settings.GDAL_LIBRARY_PATH
except (AttributeError, EnvironmentError,
ImportError, ImproperlyConfigured):
lib_path = None
if lib_path:
lib_names = None
elif == 'nt':
# Windows NT shared libraries
lib_names = ['gdal202', 'gdal201', 'gdal20', 'gdal111', 'gdal110', 'gdal19']
elif == 'posix':
# *NIX library names.
lib_names = ['gdal', 'GDAL', 'gdal2.2.0', 'gdal2.1.0', 'gdal2.0.0', 'gdal1.11.0', 'gdal1.10.0', 'gdal1.9.0']
raise ImproperlyConfigured('GDAL is unsupported on OS "%s".' %
# Using the ctypes `find_library` utility to find the
# path to the GDAL library from the list of library names.
if lib_names:
for lib_name in lib_names:
lib_path = find_library(lib_name)
if lib_path is not None:
if lib_path is None:
raise ImproperlyConfigured(
'Could not find the GDAL library (tried "%s"). Is GDAL installed? '
'If it is, try setting GDAL_LIBRARY_PATH in your settings.'
% '", "'.join(lib_names)
# This loads the GDAL/OGR C library
lgdal = CDLL(lib_path)
# On Windows, the GDAL binaries have some OSR routines exported with
# STDCALL, while others are not. Thus, the library will also need to
# be loaded up as WinDLL for said OSR functions that require the
# different calling convention.
if == 'nt':
from ctypes import WinDLL
lwingdal = WinDLL(lib_path)
def std_call(func):
Return the correct STDCALL function for certain OSR routines on Win32
if == 'nt':
return lwingdal[func]
return lgdal[func]
# #### Version-information functions. ####
# Return GDAL library version information with the given key.
_version_info = std_call('GDALVersionInfo')
_version_info.argtypes = [c_char_p]
_version_info.restype = c_char_p
def gdal_version():
"Return only the GDAL version number information."
return _version_info(b'RELEASE_NAME')
def gdal_full_version():
"Return the full GDAL version information."
return _version_info('')
version_regex = re.compile(r'^(?P<major>\d+)\.(?P<minor>\d+)(\.(?P<subminor>\d+))?')
def gdal_version_info():
ver = gdal_version().decode()
m = version_regex.match(ver)
if not m:
raise GDALException('Could not parse GDAL version string "%s"' % ver)
return {key: for key in ('major', 'minor', 'subminor')}
_verinfo = gdal_version_info()
GDAL_MAJOR_VERSION = int(_verinfo['major'])
GDAL_MINOR_VERSION = int(_verinfo['minor'])
GDAL_SUBMINOR_VERSION = _verinfo['subminor'] and int(_verinfo['subminor'])
del _verinfo
# Set library error handling so as errors are logged
CPLErrorHandler = CFUNCTYPE(None, c_int, c_int, c_char_p)
def err_handler(error_class, error_number, message):
logger.error('GDAL_ERROR %d: %s', error_number, message)
err_handler = CPLErrorHandler(err_handler)
def function(name, args, restype):
func = std_call(name)
func.argtypes = args
func.restype = restype
return func
set_error_handler = function('CPLSetErrorHandler', [CPLErrorHandler], CPLErrorHandler)