Reading files from symbolic link folder

Ignition
1

I have a symbolic link folder on the C drive of the machine running the gateway.
When I try:

os.path.exists(path)

it returns False.

When I try the same with a different folder on the C drive with the same permissions, it returns True.
Both folders appear when I try:

os.listdir('C:\\')

Any ideas why the gateway script cannot see the first folder?

2

try

os.path.islink(path)

this will return true if its a link even if it has no permissions or something

3

That also returns False.
The docs to mention that for os.path.islink(), it:

Always returns False if symbolic links are not supported by the Python runtime

I don't know if that is the case here.

4

Seems python 2.7 doesnt suppport symlinks on windows

hmm how about the igntions function? does that find it?

system.file.fileExists

5

Also no luck. Return False.

6

hmm you can try going java…

import java.io.File as File
path = "C:\\"
File(path).exists()
7

I don’t think it is an issue of python vs java.
Might be some Ignition conf setting need to change. Or maybe Ignition doesn’t like symbolic link folders.

8

maybe...

i was able to do both java and pyhton exists on a new junction symlink i made.
islink did not work tho

9

Use java’s File. It IS an issue of java vs. python. (Always use java’s alternatives to python’s stdlib in jython if you want predictable, bug-free operation.)

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10

The Java version also did not work.

However it turned out it was a permissions thing in the end. Ignition is a system account user by default, and the system account user had no permission to read/write the mapped drive. And so neither the symbolic folder.
Followed this answer and changed Ignition login to be local user. All works now.

2 Likes