Obtain the DFS path of a network location in Python - windows

Question

I want to obtain a ping-like response from a Windows network location that has a Distributed File System architecture e.g.
path = r'\\path\to\some\shared\folder_x'
delay = ping_func(path)
print delay # return response in milliseconds ?
234
Once I have host computer I can easily ping the location.
I can determine the host name for folder_x by looking at the DFS tab in the windows explorer which will look like e.g.
\\hostcomputer.server.uk\shared$\folder_x
How can I do this programmatically in Python?

Answer 1

Since you are using Windows, your always install pywin32 and WMI to get the WMI functions. And below should help you connect to remote DFS. Can't test it as I don't have Windows or DFS
import wmi
c = wmi.WMI (ip, user="user", password="pwd")
for share in c.Win32_Share (Type=0):
print share.Caption, share.Path
for session in share.associators (
wmi_result_class="Win32_ServerConnection"
):
print " ", session.UserName, session.ActiveTime

Answer 2

I've been able to directly call the NetDfsGetInfo function using Python's "ctypes" module.
Some stumbling points I had was understanding the C++/Python interface and variable marshalling - that's what the dfs.argtypes helps with.
The C++ calls return their structures by placing pointers into a buffer you supply to the call. Using byref you are matching the function prototype LPBYTE *Buffer
Processing the output requires defining a "Structure" that matches the function return, in this case DFS_INFO_3. The python "buffer" variable is cast as a pointer to DFS_INFO_3 and ctypes.Structure defines the field names and the types the struct is build from. Then you can access them via attribute name, eg, dfs_info.EntryPath
There was a pointer to a variable-length array (DFS_STORAGE_INFO) returned too, which is able to be accessed via normal Python storage[i] syntax.
import ctypes as ct
from ctypes import wintypes as win
dfs = ct.windll.netapi32.NetDfsGetInfo
dfs.argtypes = [
win.LPWSTR,
win.LPWSTR,
win.LPWSTR,
win.DWORD,
ct.POINTER(win.LPBYTE),
]
class DFS_STORAGE_INFO(ct.Structure):
"""Contains information about a DFS root or link target in a DFS namespace."""
_fields_ = [ # noqa: WPS120
("State", win.ULONG),
("ServerName", win.LPWSTR),
("ShareName", win.LPWSTR),
]
class DFS_INFO_3(ct.Structure): # noqa: WPS114
"""Contains information about a Distributed File System (DFS) root or link."""
_fields_ = [ # noqa: WPS120
("EntryPath", win.LPWSTR),
("Comment", win.LPWSTR),
("State", win.DWORD),
("NumberOfStorages", win.DWORD),
("Storage", ct.POINTER(DFS_STORAGE_INFO)),
]
# ----- Function call -----
buffer = win.LPBYTE() # allocate a LPBYTE type buffer to be used for return pointer
dret = dfs(r"\\something.else\here", None, None, 3, ct.byref(buffer))
# specify that buffer now points to a DFS_INFO_3 struct
dfs_info = ct.cast(buffer, ct.POINTER(DFS_INFO_3)).contents
print(dfs_info.EntryPath)
for i in range(dfs_info.NumberOfStorages):
storage = dfs_info.Storage[i]
print(
f"{storage.ServerName=}",
f"{storage.ShareName=}",
)