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Please support os.PathLike #11579
Description
Description
When I try to open a FITS file with a path like object which is not dircetly a pathlib.Path, I get a failure:
import os
class DummyPath(os.Pathlike):
def __init__(self, path):
self.path = path
def __fspath__(self):
return str(self.path)With the normal open, this works fine:
>>> p = DummyPath('foo.txt')
>>> fp = open(p)
>>> print(fp.read()
A big brown foxBut it does not work with astropy.io.fits:
>>> from astropy.io import fits
>>> f = DummyPath('foo.fits')
>>> fits.open(f)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python3/dist-packages/astropy/io/fits/hdu/hdulist.py", line 164, in fitsopen
return HDUList.fromfile(name, mode, memmap, save_backup, cache,
File "/usr/lib/python3/dist-packages/astropy/io/fits/hdu/hdulist.py", line 401, in fromfile
return cls._readfrom(fileobj=fileobj, mode=mode, memmap=memmap,
File "/usr/lib/python3/dist-packages/astropy/io/fits/hdu/hdulist.py", line 1052, in _readfrom
fileobj = _File(fileobj, mode=mode, memmap=memmap, cache=cache)
File "/usr/lib/python3/dist-packages/astropy/utils/decorators.py", line 535, in wrapper
return function(*args, **kwargs)
File "/usr/lib/python3/dist-packages/astropy/io/fits/file.py", line 177, in __init__
self._open_filelike(fileobj, mode, overwrite)
File "/usr/lib/python3/dist-packages/astropy/io/fits/file.py", line 541, in _open_filelike
raise OSError("File-like object does not have a 'write' "
OSError: File-like object does not have a 'write' method, required for mode 'ostream'.Having os.PathLike supported would make it easy to implement f.e. a cache, where __fspath__() could handle the creation or download of a requested file before opening.
For fits, I would guess that the problem is that pathlib.Path is hardcoded:
astropy/astropy/io/fits/file.py
Lines 134 to 136 in 8d26b90
This could be replaced with checking for os.PathLike, and accessing the string with __fspath__() instead, but there may be other places as well. A simple grep shows that isinstance(…, pathlib.Path) is used here:
io/registry.pyio/fits/util.pyio/fits/convenience.pyio/fits/file.py(this is the one shown above)io/fits/diff.pyconfig/configuration.py
Reacted by Adrian Price-Whelan
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