80 lines
2.4 KiB
Python
80 lines
2.4 KiB
Python
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"""
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pkgdata is a simple, extensible way for a package to acquire data file
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resources.
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The getResource function is equivalent to the standard idioms, such as
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the following minimal implementation:
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import sys, os
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def getResource(identifier, pkgname=__name__):
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pkgpath = os.path.dirname(sys.modules[pkgname].__file__)
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path = os.path.join(pkgpath, identifier)
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return file(os.path.normpath(path), mode='rb')
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When a __loader__ is present on the module given by __name__, it will defer
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getResource to its get_data implementation and return it as a file-like
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object (such as StringIO).
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"""
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__all__ = ["getResource"]
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import sys
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import os
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from io import BytesIO
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try:
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from pkg_resources import resource_stream, resource_exists
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except ImportError:
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def resource_exists(_package_or_requirement, _resource_name):
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"""
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A stub for when we fail to import this function.
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:return: Always returns False
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"""
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return False
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def resource_stream(_package_of_requirement, _resource_name):
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"""
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A stub for when we fail to import this function.
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Always raises a NotImplementedError when called.
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"""
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raise NotImplementedError
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def getResource(identifier, pkgname=__name__):
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"""
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Acquire a readable object for a given package name and identifier.
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An IOError will be raised if the resource can not be found.
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For example:
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mydata = getResource('mypkgdata.jpg').read()
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Note that the package name must be fully qualified, if given, such
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that it would be found in sys.modules.
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In some cases, getResource will return a real file object. In that
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case, it may be useful to use its name attribute to get the path
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rather than use it as a file-like object. For example, you may
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be handing data off to a C API.
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"""
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# When pyinstaller (or similar tools) are used, resource_exists may raise
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# NotImplemented error
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try:
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if resource_exists(pkgname, identifier):
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return resource_stream(pkgname, identifier)
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except NotImplementedError:
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pass
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mod = sys.modules[pkgname]
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path_to_file = getattr(mod, "__file__", None)
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if path_to_file is None:
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raise IOError(f"{repr(mod)} has no __file__!")
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path = os.path.join(os.path.dirname(path_to_file), identifier)
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# pylint: disable=consider-using-with
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return open(os.path.normpath(path), "rb")
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