#15644: django.core.files.base.File enhancement / fix
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Reporter: nickname123 | Owner: nobody
Status: new | Milestone: 1.3
Component: Uncategorized | Version: 1.2
Keywords: file | Triage Stage: Unreviewed
Has patch: 1 |
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Hi,
I think that django.core.files.base.File should be expanded to handle a
wider range of file objects. In my specific case, StringIO/cStringIO and
tempfile.SpooledTemporaryFile objects.
Here is a simple demonstration of where the File class breaks:
{{{
from tempfile import SpooledTemporaryFile
from django.core.files import File
f = SpooledTemporaryFile(
max_size = 1024,# 1kb
mode = 'w+b',# must be open in binary mode
bufsize = -1,
suffix = '',
prefix = 'tmp',
dir = None
)
f.write("hello")
print len(File(f))
}}}
Here is the result (on Windows using Python2.6):
{{{
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\...\django\core\files\base.py", line 33, in __len__
return self.size
File "C:\...\django\core\files\base.py", line 39, in _get_size
elif os.path.exists(self.file.name):
File "C:\...\lib\tempfile.py", line 559, in name
return self._file.name
AttributeError: 'cStringIO.StringO' object has no attribute 'name'
}}}
It should be noted that not only does the current implementation fail, but
it breaks in the wrong code block because it doesn't verify that the name
attribute is available.
I propose that the file objects seek and tell method be used as an
additional fallback before throwing the attribute error as follows:
{{{
def _get_size(self):
if not hasattr(self, '_size'):
if hasattr(self.file, 'size'):
self._size = self.file.size
elif hasattr(self.file, 'name') and
os.path.exists(self.file.name):
self._size = os.path.getsize(self.file.name)
elif hasattr(self.file, 'tell') and hasattr(self.file,
'seek'):
pos = self.file.tell()
self.file.seek(0,os.SEEK_END)
self._size = self.file.tell()
self.file.seek(pos)
else:
raise AttributeError("Unable to determine the
file's size.")
return self._size
}}}
My proposed patch fixes the problems mentioned above.
--
Ticket URL: <http://code.djangoproject.com/ticket/15644>
Django <http://code.djangoproject.com/>
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