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## 8.5 zipfile - ZIP Archive Access

# The zipfile module can be used to manipulate ZIP archive files

import zipfile, time, datetime, itertools, binascii, sys

from contextlib import closing

try:

import zlib

zip_compression = zipfile.ZIP_DEFLATED

except:

zip_compression = zipfile.ZIP_STORED

## 8.5.1 Testing ZIP Files

# Use is_zipfile() to return a Boolean indicating if it is or not

filenames = [

'data/lorem.txt',

'data/8.5-zipfile_example.zip',

'data/8.5-zipfile_bad-example.zip',

'data/8.5-zipfile_does-not-exist',

]

for filename in filenames:

print '%35s %s' % ( filename, zipfile.is_zipfile( filename ) )

print

## 8.5.2 Reading Metadata from an Archive

# use the ZipFile class to work directly on a ZIP file

# namelist() returns the names of the files in the archive

with closing( zipfile.ZipFile( filenames[1] , 'r') ) as zf:

print zf.namelist()

print

# to access the rest of the metadata, use infolist() or getinfo()

def print_info(archive_name):

fmt = "\t{:12} : {}"

with closing( zipfile.ZipFile( archive_name ) ) as zf:

for info in zf.infolist():

if info.create_system == 0:

system = 'Windows'

elif info.create_system == 3:

system = 'Unix'

else:

system = 'UNKNOWN'

print info.filename

print fmt.format( "Comment", info.comment )

print fmt.format( "Modified", datetime.datetime(*info.date_time) )

print fmt.format( "System", system )

print fmt.format( "ZIP version", info.create_version )

print fmt.format( "Compressed", info.compress_size ), "bytes"

print fmt.format( "Uncompressed", info.file_size ), "bytes"

print

print_info( filenames[1] )

# If the name of the archive member is known in advance, it can be selected directly.

with closing( zipfile.ZipFile( filenames[1], 'r' ) ) as zf:

archive_filenames = list( itertools.chain(

[info.filename for info in zf.infolist()[ :len(zf.infolist()) /2 ]],

['data/8.3-bzip_compress-level-10.bz2',]

))

for filename in archive_filenames:

try:

info = zf.getinfo( filename )

except KeyError:

print "ERROR: Did not find %s in zip file" % filename

else:

print '%s is %d bytes' % ( info.filename, info.file_size )

print

## 8.5.3 Extracting Archived Files from an Archive

# To access the data from an archive member, use the read() method, passing the name

for filename in archive_filenames:

try:

data = zf.read( filename )

except KeyError:

print "ERROR: Did not find %s in zip file" % filename

else:

print filename, ': (sample)'

print binascii.hexlify(data)[:79]

print

## 8.5.4 Creating New Archives

# Creating a new archive is as simple as opening a file with mode='w'

print "Creating archive:"

with closing( zipfile.ZipFile( archive_filenames[0], mode='w' ) ) as zf:

print "adding data/lorem.txt"

zf.write( 'data/lorem.txt' )

print

print_info( archive_filenames[0] )

# To add compression, the zlib module is required

# if zlib is available, the sompression mode for a file or the archive can be set with

# zipfile.ZIP_DEFLATED

# The default compression mode is zipfile.ZIP_STORED, which doesn't compress archived data

modes = {

zipfile.ZIP_DEFLATED: 'deflated',

zipfile.ZIP_STORED : 'stored',

}

print "Creating archive:"

with closing( zipfile.ZipFile( archive_filenames[0], mode='w' ) ) as zf:

mode = modes[zip_compression]

print "adding 'data/lorem.txt' with compression mode", mode

## 8.5.5 Using Alternative Archive Member Names

# add an arcname= value to write() to change the name of the file stored

zf.write( 'data/lorem.txt', arcname='ipsum.txt', compress_type=zip_compression )

print

print_info( archive_filenames[0] )

print

## 8.5.6 Writing Data from Source Other than Files

# Rather than writing data to file and then adding that file to the ZIP archive

# Insert the data directly into the archive from memory with writestr()

msg = "This data did not exist in a file"

with closing( zipfile.ZipFile( filenames[1], mode='w', compression=zip_compression ) ) as zf:

zf.writestr('from-string10.txt', msg * 10)

zf.writestr('from-string100.txt', msg * 100)

zf.writestr('from-string1000.txt', msg * 1000)

print_info( filenames[1] )

with closing( zipfile.ZipFile( filenames[1], 'r' ) ) as zf:

print zf.read( 'from-string10.txt' )

print

## 8.5.7 Writing with a ZipInfo Instance

# Normally the modification date is computed when the file or string is added to the archive

# A ZipInfo instance can be passed to writestr() to define the modification date and other metadata

## 8.5.8 Appending to Files

# using the mode='a' flag adds to the file instead of truncating it

with closing( zipfile.ZipFile( filenames[1], mode='a') ) as zf:

info = zipfile.ZipInfo( 'lorem.txt', date_time = time.localtime( (time.time() ) )[:6] )

info.compress_type = zip_compression

info.comment = "Remarks go here."

info.create_system=0

zf.writestr(info, msg)

print_info( filenames[1] )

## 8.5.9 Python ZIP Archives

# Python can import modules from inside aip archives using zipimport, if those archives appear in sys.path

# The PyZipFile class can be used to construct a module suitable for use this way.

# The extra method writepy() tells PyZipFile to scan a directory for .py files and add the corresponding .po or .pyc to the archive

# If neither compiled form exists, a .pyc is created and added.

with closing( zipfile.PyZipFile( 'data/8.5-zipfile_pyzipfile.zip', mode='w' ) ) as zf:

zf.debug = 3

print "Adding python files"

zf.writepy('.')

for name in zf.namelist():

print name

print

sys.path.insert(0, 'data/8.5-zipfile_pyzipfile.zip')

import zipfile_print_info

print 'Imported from:', zipfile_print_info.__file__

print

#zipfile_print_info.print_info('data/8.5-zipfile_pyzipfile.zip')

## 8.5.10 Limitations

# zipfile will not work on ZIP files with appended comments, or multidisk archives

# It also does not support files >4GB that use the ZIP64 extension