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Python zipfile 模块 – Read and write ZIP archive files

日期：2011-10-26 ｜  来源：未知 ｜  作者：redice ｜  人围观 ｜  0 人鼓掌了！

 转自：http://www.doughellmann.com/PyMOTW/zipfile/

 

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

Limitations

The zipfile module does not support ZIP files with appended comments, or multi-disk ZIP files. It does support ZIP files larger than 4 GB that use the ZIP64 extensions.

Testing ZIP Files

The is_zipfile() function returns a boolean indicating whether or not the filename passed as an argument refers to a valid ZIP file.

import zipfile

for filename in [ 'README.txt', 'example.zip', 
                  'bad_example.zip', 'notthere.zip' ]:
    print '%20s  %s' % (filename, zipfile.is_zipfile(filename))

Notice that if the file does not exist at all, is_zipfile() returns False.

$ python zipfile_is_zipfile.py

          README.txt  False
         example.zip  True
     bad_example.zip  False
        notthere.zip  False

Reading Meta-data from a ZIP Archive

Use the ZipFile class to work directly with a ZIP archive. It supports methods for reading data about existing archives as well as modifying the archives by adding additional files.

To read the names of the files in an existing archive, use namelist():

import zipfile

zf = zipfile.ZipFile('example.zip', 'r')
print zf.namelist()

The return value is a list of strings with the names of the archive contents:

$ python zipfile_namelist.py

['README.txt']

The list of names is only part of the information available from the archive, though. To access all of the meta-data about the ZIP contents, use the infolist() or getinfo() methods.

import datetime
import zipfile

def print_info(archive_name):
    zf = zipfile.ZipFile(archive_name)
    for info in zf.infolist():
        print info.filename
        print '\tComment:\t', info.comment
        print '\tModified:\t', datetime.datetime(*info.date_time)
        print '\tSystem:\t\t', info.create_system, '(0 = Windows, 3 = Unix)'
        print '\tZIP version:\t', info.create_version
        print '\tCompressed:\t', info.compress_size, 'bytes'
        print '\tUncompressed:\t', info.file_size, 'bytes'
        print

if __name__ == '__main__':
    print_info('example.zip')

There are additional fields other than those printed here, but deciphering the values into anything useful requires careful reading of the PKZIP Application Note with the ZIP file specification.

$ python zipfile_infolist.py

README.txt
        Comment:
        Modified:       2007-12-16 10:08:52
        System:         3 (0 = Windows, 3 = Unix)
        ZIP version:    23
        Compressed:     63 bytes
        Uncompressed:   75 bytes

If you know in advance the name of the archive member, you can retrieve its ZipInfo object with getinfo().

import zipfile

zf = zipfile.ZipFile('example.zip')
for filename in [ 'README.txt', 'notthere.txt' ]:
    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)

If the archive member is not present, getinfo() raises a KeyError.

$ python zipfile_getinfo.py

README.txt is 75 bytes
ERROR: Did not find notthere.txt in zip file

Extracting Archived Files From a ZIP Archive

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

import zipfile

zf = zipfile.ZipFile('example.zip')
for filename in [ 'README.txt', 'notthere.txt' ]:
    try:
        data = zf.read(filename)
    except KeyError:
        print 'ERROR: Did not find %s in zip file' % filename
    else:
        print filename, ':'
        print repr(data)
    print

The data is automatically decompressed for you, if necessary.

$ python zipfile_read.py

README.txt :
'The examples for the zipfile module use this file and example.zip as data.\n'

ERROR: Did not find notthere.txt in zip file

Creating New Archives

To create a new archive, simple instantiate the ZipFile with a mode of 'w'. Any existing file is truncated and a new archive is started. To add files, use the write() method.

from zipfile_infolist import print_info
import zipfile

print 'creating archive'
zf = zipfile.ZipFile('zipfile_write.zip', mode='w')
try:
    print 'adding README.txt'
    zf.write('README.txt')
finally:
    print 'closing'
    zf.close()

print
print_info('zipfile_write.zip')

By default, the contents of the archive are not compressed:

$ python zipfile_write.py
creating archive
adding README.txt
closing

README.txt
        Comment:
        Modified:       2007-12-16 10:08:50
        System:         3 (0 = Windows, 3 = Unix)
        ZIP version:    20
        Compressed:     75 bytes
        Uncompressed:   75 bytes

To add compression, the zlib module is required. If zlib is available, you can set the compression mode for individual files or for the archive as a whole using zipfile.ZIP_DEFLATED. The default compression mode iszipfile.ZIP_STORED.

from zipfile_infolist import print_info
import zipfile
try:
    import zlib
    compression = zipfile.ZIP_DEFLATED
except:
    compression = zipfile.ZIP_STORED

modes = { zipfile.ZIP_DEFLATED: 'deflated',
          zipfile.ZIP_STORED:   'stored',
          }

print 'creating archive'
zf = zipfile.ZipFile('zipfile_write_compression.zip', mode='w')
try:
    print 'adding README.txt with compression mode', modes[compression]
    zf.write('README.txt', compress_type=compression)
finally:
    print 'closing'
    zf.close()

print
print_info('zipfile_write_compression.zip')

This time the archive member is compressed:

$ python zipfile_write_compression.py
creating archive
adding README.txt with compression mode deflated
closing

README.txt
        Comment:
        Modified:       2007-12-16 10:08:50
        System:         3 (0 = Windows, 3 = Unix)
        ZIP version:    20
        Compressed:     63 bytes
        Uncompressed:   75 bytes

Using Alternate Archive Member Names

It is easy to add a file to an archive using a name other than the original file name, by passing the arcname argument to write().

from zipfile_infolist import print_info
import zipfile

zf = zipfile.ZipFile('zipfile_write_arcname.zip', mode='w')
try:
    zf.write('README.txt', arcname='NOT_README.txt')
finally:
    zf.close()
print_info('zipfile_write_arcname.zip')

There is no sign of the original filename in the archive:

$ python zipfile_write_arcname.py
NOT_README.txt
        Comment:
        Modified:       2007-12-16 10:08:50
        System:         3 (0 = Windows, 3 = Unix)
        ZIP version:    20
        Compressed:     75 bytes
        Uncompressed:   75 bytes

Writing Data from Sources Other Than Files

Sometimes it is necessary to write to a ZIP archive using data that did not come from an existing file. Rather than writing the data to a file, then adding that file to the ZIP archive, you can use the writestr() method to add a string of bytes to the archive directly.

from zipfile_infolist import print_info
import zipfile

msg = 'This data did not exist in a file before being added to the ZIP file'
zf = zipfile.ZipFile('zipfile_writestr.zip', 
                     mode='w',
                     compression=zipfile.ZIP_DEFLATED, 
                     )
try:
    zf.writestr('from_string.txt', msg)
finally:
    zf.close()

print_info('zipfile_writestr.zip')

zf = zipfile.ZipFile('zipfile_writestr.zip', 'r')
print zf.read('from_string.txt')

In this case, I used the compress argument to ZipFile to compress the data, since writestr() does not take compress as an argument.

$ python zipfile_writestr.py
from_string.txt
        Comment:
        Modified:       2007-12-16 11:38:14
        System:         3 (0 = Windows, 3 = Unix)
        ZIP version:    20
        Compressed:     62 bytes
        Uncompressed:   68 bytes

This data did not exist in a file before being added to the ZIP file

Writing with a ZipInfo Instance

Normally, the modification date is computed for you when you add a file or string to the archive. When using writestr(), you can also pass a ZipInfo instance to define the modification date and other meta-data yourself.

import time
import zipfile
from zipfile_infolist import print_info

msg = 'This data did not exist in a file before being added to the ZIP file'
zf = zipfile.ZipFile('zipfile_writestr_zipinfo.zip', 
                     mode='w',
                     )
try:
    info = zipfile.ZipInfo('from_string.txt', 
                           date_time=time.localtime(time.time()),
                           )
    info.compress_type=zipfile.ZIP_DEFLATED
    info.comment='Remarks go here'
    info.create_system=0
    zf.writestr(info, msg)
finally:
    zf.close()

print_info('zipfile_writestr_zipinfo.zip')

In this example, I set the modified time to the current time, compress the data, provide a false value for create_system, and add a comment.

$ python zipfile_writestr_zipinfo.py
from_string.txt
        Comment:        Remarks go here
        Modified:       2007-12-16 11:44:14
        System:         0 (0 = Windows, 3 = Unix)
        ZIP version:    20
        Compressed:     62 bytes
        Uncompressed:   68 bytes

Appending to Files

In addition to creating new archives, it is possible to append to an existing archive or add an archive at the end of an existing file (such as a .exe file for a self-extracting archive). To open a file to append to it, use mode 'a'.

from zipfile_infolist import print_info
import zipfile

print 'creating archive'
zf = zipfile.ZipFile('zipfile_append.zip', mode='w')
try:
    zf.write('README.txt')
finally:
    zf.close()

print
print_info('zipfile_append.zip')

print 'appending to the archive'
zf = zipfile.ZipFile('zipfile_append.zip', mode='a')
try:
    zf.write('README.txt', arcname='README2.txt')
finally:
    zf.close()

print
print_info('zipfile_append.zip')

The resulting archive ends up with 2 members:

$ python zipfile_append.py
creating archive

README.txt
        Comment:
        Modified:       2007-12-16 10:08:50
        System:         3 (0 = Windows, 3 = Unix)
        ZIP version:    20
        Compressed:     75 bytes
        Uncompressed:   75 bytes

appending to the archive

README.txt
        Comment:
        Modified:       2007-12-16 10:08:50
        System:         3 (0 = Windows, 3 = Unix)
        ZIP version:    20
        Compressed:     75 bytes
        Uncompressed:   75 bytes

README2.txt
        Comment:
        Modified:       2007-12-16 10:08:50
        System:         3 (0 = Windows, 3 = Unix)
        ZIP version:    20
        Compressed:     75 bytes
        Uncompressed:   75 bytes

Python ZIP Archives

Since version 2.3 Python has had the ability to import modules from inside ZIP archives if those archives appear in sys.path. The PyZipFile class can be used to construct a module suitable for use in this way. When you use the extra method writepy(), PyZipFile scans a directory for .py files and adds the corresponding .pyo or .pyc file to the archive. If neither compiled form exists, a .pyc file is created and added.

import sys
import zipfile

if __name__ == '__main__':
    zf = zipfile.PyZipFile('zipfile_pyzipfile.zip', mode='w')
    try:
        zf.debug = 3
        print 'Adding python files'
        zf.writepy('.')
    finally:
        zf.close()
    for name in zf.namelist():
        print name

    print
    sys.path.insert(0, 'zipfile_pyzipfile.zip')
    import zipfile_pyzipfile
    print 'Imported from:', zipfile_pyzipfile.__file__

With the debug attribute of the PyZipFile set to 3, verbose debugging is enabled and you can observe as it compiles each .py file it finds.

$ python zipfile_pyzipfile.py
Adding python files
Adding package in . as .
Compiling ./__init__.py
Adding ./__init__.pyc
Compiling ./zipfile_append.py
Adding ./zipfile_append.pyc
Compiling ./zipfile_getinfo.py
Adding ./zipfile_getinfo.pyc
Compiling ./zipfile_infolist.py
Adding ./zipfile_infolist.pyc
Compiling ./zipfile_is_zipfile.py
Adding ./zipfile_is_zipfile.pyc
Compiling ./zipfile_namelist.py
Adding ./zipfile_namelist.pyc
Compiling ./zipfile_printdir.py
Adding ./zipfile_printdir.pyc
Compiling ./zipfile_pyzipfile.py
Adding ./zipfile_pyzipfile.pyc
Compiling ./zipfile_read.py
Adding ./zipfile_read.pyc
Compiling ./zipfile_write.py
Adding ./zipfile_write.pyc
Compiling ./zipfile_write_arcname.py
Adding ./zipfile_write_arcname.pyc
Compiling ./zipfile_write_compression.py
Adding ./zipfile_write_compression.pyc
Compiling ./zipfile_writestr.py
Adding ./zipfile_writestr.pyc
Compiling ./zipfile_writestr_zipinfo.py
Adding ./zipfile_writestr_zipinfo.pyc
__init__.pyc
zipfile_append.pyc
zipfile_getinfo.pyc
zipfile_infolist.pyc
zipfile_is_zipfile.pyc
zipfile_namelist.pyc
zipfile_printdir.pyc
zipfile_pyzipfile.pyc
zipfile_read.pyc
zipfile_write.pyc
zipfile_write_arcname.pyc
zipfile_write_compression.pyc
zipfile_writestr.pyc
zipfile_writestr_zipinfo.pyc

Imported from: zipfile_pyzipfile.zip/zipfile_pyzipfile.pyc

See also

zipfile
The standard library documentation for this module.
zlib
ZIP compression library
tarfile
Read and write tar archives
zipimport
Import Python modules from ZIP archive.
PKZIP Application Note
Official specification for the ZIP archive format.

[日志信息]

该日志于 2011-10-26 19:33 由 redice 发表在 redice's Blog ，你除了可以发表评论外，还可以转载 “Python zipfile 模块 – Read and write ZIP archive files” 日志到你的网站或博客，但是请保留源地址及作者信息，谢谢!!    （尊重他人劳动，你我共同努力）
   
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