[Import-SIG] Loading Resources From a Python Module/Package
vinay_sajip at yahoo.co.uk
Mon Feb 23 00:02:35 CET 2015
PJ Eby <pje <at> telecommunity.com> writes:
> Apart from that, the implementations in pkg_resources can mostly be
> pulled for reuse, as well as the interfaces, and I'd suggest doing
> exactly that. There are a lot of non-obvious gotchas dealing with
> zipfiles, and the implementation is fairly battle-hardened at this
I'm a bit late to this thread, but never mind :-)
Another possibility is to use distlib's resource implementation, which
offers the same basic functionality as is being proposed / pkg_resources,
along with a higher level API which I find easier to use. The API works
uniformly with both filesystem resources and resources in zip files.
finder = distlib.resources.Finder('package.name')
resource = finder.find('resource.bin') # could be 'nested/resource.bin
If there's no such resource, find() returns None. Otherwise, you can do a
number of things with resource via its properties:
is_container - Whether this instance is a container of other resources.
bytes - All of the resource data as a byte string.
size - The size of the resource data in bytes.
resources - The relative names of all the contents of this resource.
path - This attribute is set by the resource’s finder. It is a textual
representation of the path, such that if a PEP 302 loader’s get_data()
method is called with the path, the resource’s bytes are returned by the
loader. This attribute is analogous to the resource_filename API in
setuptools. Note that for resources in zip files, the path will be a pointer
to the resource in the zip file, and not directly usable as a filename.
While setuptools deals with this by extracting zip entries to cache and
returning filenames from the cache, this does not seem an appropriate thing
to do in this package, as a resource is already made available to callers
either as a stream or a string of bytes.
file_path - This attribute is the same as the path for file-based resource.
For resources in a .zip file, the relevant resource is extracted to a file
in a cache in the file system, and the name of the cached file is returned.
This is for use with APIs that need file names, or need to be able to access
data through OS-level file handles.
The resource also as an as_stream() method, which returns a binary stream of
the resource’s data. This must be closed by the caller when it’s finished
There's a little more than I've mentioned here. Tutorial documentation is
available at  and reference documentation is available at .
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