Python CGI - Presenting a zip file to user

[jwwest]

Hi all,

I'm working on a cgi script that zips up files and presents the zip
file to the user for download. It works fine except for the fact that
I have to overwrite the file using the same filename because I'm
unable to delete it after it's downloaded. The reason for this is
because after sending "Location: urlofzipfile" the script stops
processing and I can't call a file operation to delete the file. Thus
I constantly have a tmp.zip file which contains the previously
requested files.

Can anyone think of a way around this? Is there a better way to create
the zip file and present it for download "on-the-fly" than editing the
Location header? I thought about using Content-Type, but was unable to
think of a way to stream the file out.

Any help is appreciated, much thanks!

- James

 

[Justin Ezequiel]

Hi all,

I'm working on a cgi script that zips up files and presents the zip
file to the user for download. It works fine except for the fact that
I have to overwrite the file using the same filename because I'm
unable to delete it after it's downloaded. The reason for this is
because after sending "Location: urlofzipfile" the script stops
processing and I can't call a file operation to delete the file. Thus
I constantly have a tmp.zip file which contains the previously
requested files.

Can anyone think of a way around this? Is there a better way to create
the zip file and present it for download "on-the-fly" than editing the
Location header? I thought about using Content-Type, but was unable to
think of a way to stream the file out.

Any help is appreciated, much thanks!

- James

import sys, cgi, zipfile, os
from StringIO import StringIO

try: # Windows only
import msvcrt
msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
except ImportError: pass

HEADERS = '\r\n'.join(
[
"Content-type: %s;",
"Content-Disposition: attachment; filename=%s",
"Content-Title: %s",
"Content-Length: %i",
"\r\n", # empty line to end headers
]
)

if __name__ == '__main__':
os.chdir(r'C:\Documents and Settings\Justin Ezequiel\Desktop')
files = [
'4412_ADS_or_SQL_Server.pdf',
'Script1.py',
'html_files.zip',
'New2.html',
]
b = StringIO()
z = zipfile.ZipFile(b, 'w', zipfile.ZIP_DEFLATED)
for n in files:
z.write(n, n)

z.close()

length = b.tell()
b.seek(0)
sys.stdout.write(
HEADERS % ('application/zip', 'test.zip', 'test.zip', length)
)
sys.stdout.write(b.read())
b.close()

 

[jwwest]

Hi all,

I'm working on a cgi script that zips up files and presents the zip
file to the user for download. It works fine except for the fact that
I have to overwrite the file using the same filename because I'm
unable to delete it after it's downloaded. The reason for this is
because after sending "Location: urlofzipfile" the script stops
processing and I can't call a file operation to delete the file. Thus
I constantly have a tmp.zip file which contains the previously
requested files.

Can anyone think of a way around this? Is there a better way to create
the zip file and present it for download "on-the-fly" than editing the
Location header? I thought about using Content-Type, but was unable to
think of a way to stream the file out.

Any help is appreciated, much thanks!

- James

import sys, cgi, zipfile, os
from StringIO import StringIO

try: # Windows only
import msvcrt
msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)
except ImportError: pass

HEADERS = '\r\n'.join(
[
"Content-type: %s;",
"Content-Disposition: attachment; filename=%s",
"Content-Title: %s",
"Content-Length: %i",
"\r\n", # empty line to end headers
]
)

if __name__ == '__main__':
os.chdir(r'C:\Documents and Settings\Justin Ezequiel\Desktop')
files = [
'4412_ADS_or_SQL_Server.pdf',
'Script1.py',
'html_files.zip',
'New2.html',
]
b = StringIO()
z = zipfile.ZipFile(b, 'w', zipfile.ZIP_DEFLATED)
for n in files:
z.write(n, n)

z.close()

length = b.tell()
b.seek(0)
sys.stdout.write(
HEADERS % ('application/zip', 'test.zip', 'test.zip', length)
)
sys.stdout.write(b.read())
b.close()

Thanks! That worked like an absolute charm.

Just a question though. I'm curious as to why you have to use the
msvcrt bit on Windows. If I were to port my app to *NIX, would I need
to do anything similar?

- James

 

[Justin Ezequiel]

Thanks! That worked like an absolute charm.

Just a question though. I'm curious as to why you have to use the
msvcrt bit on Windows. If I were to port my app to *NIX, would I need
to do anything similar?

- James

not needed for *NIX as *NIX does not have a notion of binary- vs text-
mode

I seem to recall not needing the msvcrt stuff a while ago on Windows
but recently needed it again for Python CGI on IIS