Opening a file which is a symlink in Python

问题

I have some python code that opens a file to read it like so...

with open("file.txt") as f:
    print(f.read())

On MacOS, if file.txt is a symlink - Python will follow the symlink and read the target file. However, on Windows it does not do this - how can I achieve this?

(Using Python version 3.6.5 and Windows 10) Steps to reproduce.

1. Create FileA.txt in DirectoryA which is above DirectoryB
2. Inside DirectoryB, Run mlink FileA.txt "../FileA.txt"
3. Run a Python script which attempts to read and print from the FileA.txt link in DirectoryB

Expected Behaviour:

The contents of FileA.txt inside DirectoryA should be printed

Actual Behaviour:

OSError: [Errno 22] Invalid argument: 'FileA.txt'

回答1:

Something else has gone wrong. I strongly suspect that you're not running this from the directory that contains file.txt.

I'm using Windows 10, and Python 3.6.

Here I am creating a file (using trusty notepad). I added some text to the file during the first line, and verified that it was present in the second.

cd c:\
notepad test.txt
mklink other.txt test.txt
notepad other.txt

Now over to python...

f = open("C:\\other.txt")
f.read()

This all worked for me. More details will be required in order to assist you, but as it stands your problem is not reproducible.

---

Now that you've updated your question with exact steps I can tell you exactly what's going wrong.

But first - try opening that file in notepad (or anything else).

It won't open - instead it'll give a file error.

This is because of the path you've given it. Windows uses \ for directory seperators - but you've used / to create the symlink. This symlink points to an invalid filename. Python is nice enough (being crossplatform) to convert it for you - but windows does no such thing.

Try your instructions again - but this time use mklink FileA.txt "..\FileA.txt"

回答2:

I don’t do MS Windows. But this might help: http://winshell.readthedocs.io/en/latest/shortcuts.html

Does your version of MS Windows actually support symlinks? Or are you dealing with these “shortcuts” (Shell links)? Does it actually have a .lnk extension?

来源：https://stackoverflow.com/questions/50321207/opening-a-file-which-is-a-symlink-in-python