List,
How do I create a file which exists only in memory? (Think diskless.)
I need to create an in-memory file. I need to pass this file, as a
regular file object, to a subprocess. Unfortunately, the 'mmap'
module's file-like object doesn't appear to work quite like a regular
file would. (I simply assume that mmap would be the way to go. Other
suggestions welcome!) That, or I'm doing something terribly wrong. For
example:
import mmap
import sys
from subprocess import Popen, PIPE
fishes = "one fish\ntwo fish\nred fish\nblue fish\n"
#######################################
# With a real file, this works:
#######################################
fd = open('fish.txt', 'w')
fd.write(fishes)
fd = open('fish.txt', 'r')
proc1 = Popen(['cat'], stdin=fd, stdout=sys.stdout, stderr=sys.stderr)
#######################################
# This doesn't (with mmap file):
#######################################
vfd = mmap.mmap(-1, len(fishes), mmap.MAP_PRIVATE)
vfd.write(fishes)
vfd.seek(0)
proc2 = Popen(['cat'], stdin=vfd.fileno(), stdout=sys.stdout, stderr=sys.stderr)
I just get the following error:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: fileno
I'm using Python 2.5, so I cannot use that slick
'SpooledTemporaryFile' method of the 'tempfile' module. The 'cat' is
just a simple Unix system command for the purpose of illustration.
Thanks!
-Modulok-
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