Permission denied when trying to write to file from a view

Question

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I have a view that attempts to execute f = open('textfile.txt', 'w') but on my live server this brings up the error [Errno 13] Permission denied: 'textfile.txt'.

My file structure is as follows:

- root
    |
    - project
          |
          - app
          |
          - media

where the view lives in app.

I have tried having textfile.txt live in root, project, app and media all of which have 777 file permissions (owner, group and public can read, write and execute)[*1].

If I change the command to a read permission ie f = open('textfile.txt', 'r') I get the same error.

My media root is set to os.path.join(os.path.dirname(__file__), 'media').replace('\\','/') and this is all running on an apache server through webfaction.

So I have two questions. Where is django/python trying to open this file from? and what do I need to change to get permission for the view to open and write to the file.

[*1] I know this is not a good idea, I just have this set for current debugging purposes.

---

EDIT:

I don't know if this is relevant but now when I change it to f = open(os.path.join(settings.MEDIA_URL, 'textfile.txt'), 'r') rather than f = open(os.path.join(settings.MEDIA_URL, 'textfile.txt'), 'w') I get the error [Errno 2] No such file or directory.

I don't know if this has meaning or not...

Answer 1

Given the following:

f = open('textfile.txt', 'w')

It should be creating the file in same directory as __file__, the currently running script or views.py in your scenario.

However, it's better to be explicit, and therefore rule out any potential deviations. I'd recommend changing that line to:

import os
f = open(os.path.join(os.path.dirname(__file__), 'textfile.txt'), 'w')

Or even better, something like:

import os
from django.conf import settings
f = open(os.path.join(settings.MEDIA_ROOT, 'textfile.txt'), 'w')

Then, you're always assured exactly where the file is being saved, which should allow you to optimize your permissions more appropriately. Alternatively, you can use a PROJECT_ROOT.