I've got tar files filled with images that I'm trying to read with PIL. I'm
using the following snipit:
if file.endswith( ".tar" ):
# Read image files out of tar and into memory
tar = tarfile.open( file , "r:" )
item = [] #hold a link to a file object
for tarinfo in tar:
fileobj = tar.extractfile( tarinfo )
im = Image.open( fileobj )
item.append( im )
This doesn't work, I get an exception:
Traceback (most recent call last):
File "ImageWorker.py", line 84, in <module>
results = process( source_files , commands )
File "ImageWorker.py", line 28, in process
im = Image.open( fileobj )
File "/usr/lib/python2.5/site-packages/PIL/Image.py", line 1917, in open
raise IOError("cannot identify image file")
IOError: cannot identify image file
This is odd, because the docs for Image.open say:
" You can use either a string (representing the filename) or a file object.
In the latter case, the file object must implement read, seek, and tell
methods, and be opened in binary mode."
And the docs for Tar.extractfile say:
"Note: The file-like object is read-only and provides the following methods:
read(), readline(), readlines(), seek(), tell()."
So it seems that contracts are all met. A little bit of googling suggested
that the TarIO module might be useful, but I can't seem to find this on PIL
module reference page:
http://www.pythonware.com/library/pil/handbook/index.htm
My question is thus:
1. What's the best practice for reading images out of a tar file with pil
and into in-memory Image objects?
2. Which of PIL.open() or the Tar.extractfile() is incorrect in their
documentation, and where would I file this as a bug if it is PIL (even if
it's just a bug in PILs documentation)?
Thanks for any thoughts,
Chris
--
Christopher Brooks, MSc.
Web: http://www.cs.usask.ca/~cab938
Mail: Advanced Research in Intelligent Educational Systems Laboratory
Department of Computer Science
University of Saskatchewan
176 Thorvaldson Building
110 Science Place
Saskatoon, SK
S7N 5C9
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