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import imp
import os
import sys
from django.core.exceptions import ImproperlyConfigured
from django.utils import six
from django.utils.importlib import import_module
def import_by_path(dotted_path, error_prefix=''):
"""
Import a dotted module path and return the attribute/class designated by the
last name in the path. Raise ImproperlyConfigured if something goes wrong.
"""
try:
module_path, class_name = dotted_path.rsplit('.', 1)
except ValueError:
raise ImproperlyConfigured("%s%s doesn't look like a module path" % (
error_prefix, dotted_path))
try:
module = import_module(module_path)
except ImportError as e:
msg = '%sError importing module %s: "%s"' % (
error_prefix, module_path, e)
six.reraise(ImproperlyConfigured, ImproperlyConfigured(msg),
sys.exc_info()[2])
try:
attr = getattr(module, class_name)
except AttributeError:
raise ImproperlyConfigured('%sModule "%s" does not define a "%s" attribute/class' % (
error_prefix, module_path, class_name))
return attr
def module_has_submodule(package, module_name):
"""See if 'module' is in 'package'."""
name = ".".join([package.__name__, module_name])
try:
# None indicates a cached miss; see mark_miss() in Python/import.c.
return sys.modules[name] is not None
except KeyError:
pass
try:
package_path = package.__path__ # No __path__, then not a package.
except AttributeError:
# Since the remainder of this function assumes that we're dealing with
# a package (module with a __path__), so if it's not, then bail here.
return False
for finder in sys.meta_path:
if finder.find_module(name, package_path):
return True
for entry in package_path:
try:
# Try the cached finder.
finder = sys.path_importer_cache[entry]
if finder is None:
# Implicit import machinery should be used.
try:
file_, _, _ = imp.find_module(module_name, [entry])
if file_:
file_.close()
return True
except ImportError:
continue
# Else see if the finder knows of a loader.
elif finder.find_module(name):
return True
else:
continue
except KeyError:
# No cached finder, so try and make one.
for hook in sys.path_hooks:
try:
finder = hook(entry)
# XXX Could cache in sys.path_importer_cache
if finder.find_module(name):
return True
else:
# Once a finder is found, stop the search.
break
except ImportError:
# Continue the search for a finder.
continue
else:
# No finder found.
# Try the implicit import machinery if searching a directory.
if os.path.isdir(entry):
try:
file_, _, _ = imp.find_module(module_name, [entry])
if file_:
file_.close()
return True
except ImportError:
pass
# XXX Could insert None or NullImporter
else:
# Exhausted the search, so the module cannot be found.
return False
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