Source code for traits.util.resource
# (C) Copyright 2005-2022 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
""" Utility functions for managing and finding resources (e.g. images, files).
get_path : Returns the absolute path of a class or instance
create_unique_name : Creates a name with a given prefix that is not in a
given list of existing names. The separator between
the prefix and the rest of the name can also be
specified (default is a '_')
find_resource: Given a setuptools project specification string
('MyProject>=2.1') and a partial path leading from the
projects base directory to the desired resource, will
return either an opened file object or, if specified,
a full path to the resource.
"""
# Standard library imports.
import inspect
import os
import sys
import sysconfig
import warnings
[docs]def get_path(path):
""" Returns an absolute path for the specified path.
'path' can be a string, class or instance.
"""
if type(path) is not str:
# Is this a class or an instance?
if inspect.isclass(path):
klass = path
else:
klass = path.__class__
# Get the name of the module that the class was loaded from.
module_name = klass.__module__
# Look the module up.
module = sys.modules[module_name]
if module_name == "__main__":
dirs = [os.path.dirname(sys.argv[0]), os.getcwd()]
for d in dirs:
if os.path.exists(d):
path = d
break
else:
# Get the path to the module.
path = os.path.dirname(module.__file__)
return path
[docs]def create_unique_name(prefix, names, separator="_"):
""" Creates a name starting with 'prefix' that is not in 'names'. """
i = 1
name = prefix
while name in names:
name = prefix + separator + str(i)
i += 1
return name
[docs]def find_resource(project, resource_path, alt_path=None, return_path=False):
""" Returns a file object or file path pointing to the desired resource.
This function will find a desired resource file and return an opened file
object. The main method of finding the resource uses the pkg_resources
resource_stream method, which searches your working set for the installed
project specified and appends the resource_path given to the project
path, leading it to the file. If setuptools is not installed or it cannot
find/open the resource, find_resource will use the sys.path[0] to find the
resource if alt_path is defined.
.. deprecated:: 6.3.0
Parameters
----------
project : str
The name of the project to look for the resource in. Can be the name or
a requirement string. Ex: 'MyProject', 'MyProject>1.0',
'MyProject==1.1'
resource_path : str
The path to the file from inside the package. If the file desired is
MyProject/data/image.jpg, resource_path would be 'data/image.jpg'.
alt_path : str
The path to the resource relative to the location of the application's
top-level script (the one with __main__). If this function is called in
code/scripts/myscript.py and the resource is code/data/image.jpg, the
alt_path would be '../data/image.jpg'. This path is only used if the
resource cannot be found using setuptools.
return_path : bool
Determines whether the function should return a file object or a full
path to the resource.
Returns
-------
file : file object or file path
A file object containing the resource. If return_path is True, 'file'
will be the full path to the resource. If the file is not found or
cannot be opened, None is returned.
"""
warnings.warn(
"find_resource is deprecated. Use importlib.resources instead.",
DeprecationWarning,
stacklevel=2,
)
try:
# Get the image using the pkg_resources resource_stream module, which
# will find the file by getting the Chaco install path and appending
# the image path. This method works in all cases as long as setuptools
# is installed. If setuptools isn't installed, the backup sys.path[0]
# method is used.
from pkg_resources import resource_stream, working_set, Requirement
# Get a requirement for the project
requirement = Requirement.parse(project)
if return_path:
dist = working_set.find(requirement)
full_path = os.path.join(dist.location, resource_path)
# If the path exists, return it
if os.path.exists(full_path):
return full_path
else:
raise
else:
return resource_stream(requirement, resource_path)
except:
# Setuptools was either not installed, or it failed to find the file.
# First check to see if the package was installed using egginst by
# looking for the file at: site-packages\\resource_path
full_path = os.path.join(sysconfig.get_path('purelib'), resource_path)
if os.path.exists(full_path):
if return_path:
return full_path
else:
return open(full_path, "rb")
# Get the image using sys.path[0], which is the directory that the
# running script lives in. The path to the file is then constructed by
# navigating from the script's location. This method only works if this
# script is called directly from the command line using
# 'python %SOMEPATH%/<script>'
if alt_path is None:
return None
if return_path:
return os.path.join(sys.path[0], alt_path)
# Try to open the file, return None on exception
try:
return open(os.path.join(sys.path[0], alt_path), "rb")
except:
return None
[docs]def store_resource(project, resource_path, filename):
""" Store the content of a resource, given by the name of the project
and the path (relative to the root of the project), into a newly
created file.
The first two arguments (project and resource_path) are the same
as for the function find_resource in this module. The third
argument (filename) is the name of the file which will be created,
or overwritten if it already exists.
The return value in always None.
.. deprecated:: 6.3.0
"""
warnings.warn(
"store_resource is deprecated. Use importlib.resources instead.",
DeprecationWarning,
stacklevel=2,
)
fi = find_resource(project, resource_path)
if fi is None:
raise RuntimeError(
'Resource not found for project "%s": %s'
% (project, resource_path)
)
with open(filename, "wb") as fo:
fo.write(fi.read())
fi.close()
