PEP 302——新的导入挂钩指定了挂钩 Python 导入机制的方法。其中之一是创建一个模块查找器/加载器并将其添加到sys.meta_path
.
我寻求创建一个能够重新路由子包导入的模块查找器。所以假设我写import mypackage.sub
它应该实际导入模块mypackage_sub
。
mypackage.sub => mypackage_sub
mypackage.sub.another => mypackage_sub.another
mypackage.sub.another.yikes => mypackage_sub.another.yikes
我尝试在不成功的地方实现这样的模块查找器。现在,我将查找器类安装在 Python 主文件中,但我的目标是将它安装在根包mypackage
中。
finder 将收到与 的电话.find_module(fullname, path)
,'mypackage'
但永远不会与'mypackage.sub'
。因此,我只收到以下代码的以下错误。
Traceback (most recent call last):
File "test.py", line 63, in <module>
import mypackage.sub
ImportError: No module named sub
import sys
sys.meta_path.append(_ExtensionFinder('mypackage'))
import mypackage.sub
这是该_ExtensionFinder
课程的代码。我感谢任何允许我将此类_ExtensionFinder
放入根模块的解决方案mypackage
。
class _ExtensionFinder(object):
"""
This class implements finding extension modules being imported by
a prefix. The dots in the prefix are converted to underscores and
will then be imported.
.. seealso:: PEP 302 -- New Import Hooks
"""
def __init__(self, prefix):
super(_ExtensionFinder, self).__init__()
self.prefix = prefix
def _transform_name(self, fullname):
if self.prefix == fullname:
return fullname
elif fullname.startswith(self.prefix + '.'):
newpart = fullname[len(self.prefix) + 1:]
newname = self.prefix.replace('.', '_') + '_' + newpart
return newname
return None
def find_module(self, fullname, path=None):
print "> find_module({0!r}, {1!r})".format(fullname, path)
newname = self._transform_name(fullname)
if newname:
return self
def load_module(self, fullname):
print "> load_module({0!r})".format(fullname)
# If there is an existing module object named 'fullname'
# in sys.modules, the loader must use that existing module.
if fullname in sys.modules:
return sys.modules[fullname]
newname = self._transform_name(fullname)
if newname in sys.modules:
sys.modules[fullname] = sys.modules[newname]
return sys.modules[newname]
# Find and load the module.
data = imp.find_module(newname)
mod = imp.load_module(newname, *data)
# The __loader__ attribute must be set to the loader object.
mod.__loader__ = self
# The returned module must have a __name__, __file__
# and __package__ attribute.
assert all(hasattr(mod, n) for n in ['__name__', '__file__', '__package__'])
return mod
编辑:我发现描述我想要实现的正确词语是“命名空间包”