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? try: from django.conf import settings lib_path = settings.GDAL_LIBRARY_PATH except (AttributeError, ImportError, ImproperlyConfigured, OSError): lib_path = None if lib_path: lib_names = None elif os.name == 'nt': # Windows NT shared libraries lib_names = ['gdal204', 'gdal203', 'gdal202', 'gdal201', 'gdal20'] elif os.name == 'posix': # *NIX library names. lib_names = ['gdal', 'GDAL', 'gdal2.4.0', 'gdal2.3.0', 'gdal2.2.0', 'gdal2.1.0', 'gdal2.0.0'] else: raise ImproperlyConfigured('GDAL is unsupported on OS "%s".' % os.name) # 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: break 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 os.name == 'nt': from ctypes import WinDLL lwingdal = WinDLL(lib_path) def std_call(func): """ Return the correct STDCALL function for certain OSR routines on Win32 platforms. """ if os.name == 'nt': return lwingdal[func] else: 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\d+)\.(?P\d+)(\.(?P\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: m.group(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']) GDAL_VERSION = (GDAL_MAJOR_VERSION, GDAL_MINOR_VERSION, GDAL_SUBMINOR_VERSION) 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) set_error_handler(err_handler)