Write Files to tempfile.TemporaryDirectory Python

Question

I would like to open and write to files in python's tempfile.TemporaryDirectory()

This is my code so far:

import tempfile

temp_dir = tempfile.TemporaryDirectory()

destination = temp_dir.name
file = 'concept_aliases.json'
spath = os.path.join(destination,"/",file)
with open(spath, "w+") as f::
   # do smthg

However, I am getting this error:

PermissionError: [Errno 13] Permission denied: '/concept_aliases.json'

Answer 1

The problem here is the slash / that is passed as the second argument to the os.path.join() method. As per documentation , join() does the following:

Join one or more path components intelligently. The return value is the concatenation of path and any members of *paths with exactly one directory separator following each non-empty part except the last, meaning that the result will only end in a separator if the last part is empty. If a component is an absolute path, all previous components are thrown away and joining continues from the absolute path component.

The crucial part however, is the following sentence:

If a component is an absolute path, all previous components are thrown away and joining continues from the absolute path component.

By passing a slash / as the second argument to join() , you actually start a new absolute path which, in return, discards all previous components.

With that being said, the correct approach in this context would be the following:

spath = os.path.join(destination, file)