I have a Python project in which I am using many non-code files. Currently these are all images, but I might use other kinds of files in the future. What would be a good scheme for storing and referencing these files?
I considered just making a folder "resources" in the main directory, but there is a problem; Some images are used from within sub-packages of my project. Storing these images that way would lead to coupling, which is a disadvantage.
Also, I need a way to access these files which is independent on what my current directory is.
You may want to use pkg_resources
library that comes with setuptools
.
For example, I've made up a quick little package "proj"
to illustrate the resource organization scheme I'd use:
proj/setup.py proj/proj/__init__.py proj/proj/code.py proj/proj/resources/__init__.py proj/proj/resources/images/__init__.py proj/proj/resources/images/pic1.png proj/proj/resources/images/pic2.png
Notice how I keep all resources in a separate subpackage.
"code.py"
shows how pkg_resources
is used to refer to the resource objects:
from pkg_resources import resource_string, resource_listdir
# Itemize data files under proj/resources/images:
print resource_listdir('proj.resources.images', '')
# Get the data file bytes:
print resource_string('proj.resources.images', 'pic2.png').encode('base64')
If you run it, you get:
['__init__.py', '__init__.pyc', 'pic1.png', 'pic2.png'] iVBORw0KGgoAAAANSUhE ...
If you need to treat a resource as a fileobject, use resource_stream()
.
The code accessing the resources may be anywhere within the subpackage structure of your project, it just needs to refer to subpackage containing the images by full name: proj.resources.images
, in this case.
Here's "setup.py"
:
#!/usr/bin/env python
from setuptools import setup, find_packages
setup(name='proj',
packages=find_packages(),
package_data={'': ['*.png']})
Caveat:
To test things "locally", that is w/o installing the package first, you'll have to invoke your test scripts from directory that has setup.py
. If you're in the same directory as code.py
, Python won't know about proj
package. So things like proj.resources
won't resolve.