Change file to read-only mode in Python

Question

I am writing a data processing code, in which I create a new file, write processed data in to this file and close. But the file has to be closed in read-only mode, so that i

Answer 1

I guess you could use os module after writing on your file to change the file permissions like this:

import os
filename=open("file_name","w")
filename.write("my text")
filename.close()
os.system("chmod 444 file_name")

Answer 2

For this you use os.chmod

import os
from stat import S_IREAD, S_IRGRP, S_IROTH

filename = "path/to/file"
os.chmod(filename, S_IREAD|S_IRGRP|S_IROTH)

Note that this assumes you have appropriate permissions, and that you want more than just the owner to be able to read the file. Remove S_IROTH and S_IRGRP as appropriate if that's not the case.

UPDATE

If you need to make the file writable again, simply call os.chmod as so:

from stat import S_IWUSR # Need to add this import to the ones above

os.chmod(filename, S_IWUSR|S_IREAD) # This makes the file read/write for the owner

Simply call this before you open the file for writing, then call the first form to make it read-only again after you're done.

Answer 3

This solution preserves previous permission of the file, acting like command chmod -w FILE

import os
import stat

filename = "path/to/file"
mode = os.stat(filename).st_mode
ro_mask = 0777 ^ (stat.S_IWRITE | stat.S_IWGRP | stat.S_IWOTH)
os.chmod(filename, mode & ro_mask)    

Answer 4

For Windows OS maybe to try something like this:

import os

filename = open("file_name.txt", "w")
filename.write("my text")
filename.close()
os.system("attrib +r file_name.txt")