This simple import hook can resolve Windows shortcuts refering to directories. This allows Windows users to simulate UNIX directory structures which contain symlinks.
Python, 82 lines
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import os
from imp import PKG_DIRECTORY
from win32com.shell import shell
import pythoncom
def resolve_shortcut(filename):
"""resolve_shortcut("Notepad.lnk") => "C:\WINDOWS\system32\notepad.exe"
Returns the path refered to by a windows shortcut (.lnk) file.
"""
shell_link = pythoncom.CoCreateInstance(
shell.CLSID_ShellLink, None,
pythoncom.CLSCTX_INPROC_SERVER, shell.IID_IShellLink)
persistant_file = shell_link.QueryInterface(pythoncom.IID_IPersistFile)
persistant_file.Load(filename)
shell_link.Resolve(0, 0)
linked_to_file = shell_link.GetPath(shell.SLGP_UNCPRIORITY)[0]
return linked_to_file
def get_shortcut_paths(directory):
"""get_shortcut_paths("Programs") => ["...\Internet Explorer.lnk", ...]
Returns the list of Windows shortcuts contained in a directory.
"""
return [os.path.join(directory, f) for f in os.listdir(directory)
if os.path.splitext(f)[1] == '.lnk']
class ShortcutLoader(ihooks.ModuleLoader):
"""A hook to resolve Python imports through Windows shortcuts"""
def recursive_match(self, name, dir, level=1):
names = name.split('.')
short_name = names[0]
remaining_names = names[1:]
try:
pairs = [(f, resolve_shortcut(f)) for f in get_shortcut_paths(dir)]
except WindowsError:
# might not have permissions, shortcut might be broken, etc.
pass
else:
for alias, resolved_path in pairs:
if (os.path.splitext(os.path.basename(alias))[0] ==
short_name) and \
os.path.isdir(resolved_path) and \
os.path.exists(os.path.join(resolved_path, '__init__.py')):
if len(remaining_names) > 0:
next_part = self.recursive_match(
'.'.join(remaining_names),
resolved_path,
level + 1)
if next_part is not None:
return os.path.join(resolved_path, next_part)
else:
return resolved_path
return None
def find_module_in_dir(self, name, dir, allow_packages=1):
if dir is None:
return ihooks.ModuleLoader.find_module_in_dir(
self, name, dir, allow_packages)
else:
if allow_packages:
resolved_path = self.recursive_match(name, dir)
if resolved_path is not None:
return (None, resolved_path, ('', '', PKG_DIRECTORY))
return ihooks.ModuleLoader.find_module_in_dir(
self, name, dir, allow_packages)
def install():
"""Install the import hook"""
ihooks.install(ihooks.ModuleImporter(ShortcutLoader()))
|
This code can be used to simulate some UNIX directory structures containing symlinks. My particular use case was:
user/pylib ui ... project2/pylib ui ... project3/pylib ui ... python-packages/user => /user/pylib project2 => /project2/pylib project3 => /project3/pylib
This implementation only resolves shortcuts refering to directories, not ones refering to files.
Tags: sysadmin
