zipfile模块是处理zip压缩包的模块, 用于压缩和解压, 添加, 和列出压缩包内容. ZipFile是主要的类(即一般意义的压缩包罗), 其过程是将每个文件及相关信息作为ZipInfo对象操作到ZipFile压缩包中. ZipInfo是ZipFile的成员(member),包括文件头信息, 文件内容.

zipfile模块

内含三个类: ZipFile, PyZipFile, ZipInfo, 一个判断函数is_zipfile, 一些常量和exception. 和tarfile不同,没有直接open返回ZipFile对象的方法, 取而代之用ZipFile类的初始化函数构建. 所以用法会有所差异.

ZipFile类

压缩包对象. 主要是构建ZipFile类, 关闭, 获取文件ZipInfo, 提取和写入, 设置密码等一些控制压缩包的方法.

• zipfile.ZipFile(file[, mode[, compression[, allowZip64]]]): 返回压缩包对象. file可以是文件名或对象, mode为’w’, ‘r’, ‘a’三种, 对应写读和追加. compression是压缩模式, ZIP_STORED (只储存不压缩)或 ZIP_DEFLATED, 默认前者, 后者需要zlib模块. allowZip64默认False, True时后缀为zip64, 可以大于2GB.
• close() 关闭打开的压缩包
• open(name[,mode[,pwd]]) 打开压缩包内的文件返回类文件对象(ZipExtFile, 只能进行读取). 并不是打开压缩包! name是压缩包内的文件名或ZipInfo对象; mode是’r’,’U’,’rU’, 默认r. pwd当有密码时使用. read(name[,pwd]) 和上类似, 但返回的是字节内容.
• getinfo(name) 通过文件名返回ZipInfo对象. infolist()返回所有ZipInfo成员的列表. namelist()返回所有ZipInfo成员的名称的列表.
• extract(member[,path[,pwd]]) 解压一个文件, member是文件名/ZipInfo对象; path解压路径, 默认’.’解压到当前文件夹; pwd是密码啦. 返回解压文件/文件夹的绝对路径.
• extractall([path[,members[,pwd]]) 解压所有(部分)文件, 基本同上. members可以指定部分文件名,namelist()的子集.
• printdir() 输出压缩包内文件信息到屏幕
• setpassword(pwd) 设置缺省密码, 可以方便解压.
• testzip() 会检查所有文件, 返回有错的文件的文件名.
• write(filename[, arcname[, compress_type]]) 将文件写入压缩包. arcname是文件在压缩包里的别名. 类似地writestr(zinfo_or_arcname, bytes[, compress_type]) 写byte串到压缩包.

ZipInfo类

就是压缩包的一个成员member. 其实质是文件+相关信息. 主要有一些属性.例如属性: filename, date_time, file_size等. 一般情况下, ZipInfo通过ZipFile的 getinfo(name)或infolist()获取.

例如

z = zipfile.ZipFile(filename, 'r')

for i in z.infolist():
    print i.file_size, i.header_offset
    z.extract(i)
z.close()

z = zipfile.ZipFile(filename, 'w') 

#把testdir中的文件全部添加到压缩包里（这里只添加一级子目录中的文件）：
if os.path.isdir(testdir):
    for d in os.listdir(testdir):
        z.write(testdir+os.sep+d)
z.close()

zipfile module reference

zipfile module

The ZIP file format is a common archive and compression standard. This module provides tools to create, read, write, append, and list a ZIP file. Any advanced use of this module will require an understanding of the format, as defined in PKZIP Application Note.

This module does not currently handle multi-disk ZIP files. It can handle ZIP files that use the ZIP64 extensions (that is ZIP files that are more than 4 GByte in size). It supports decryption of encrypted files in ZIP archives, but it currently cannot create an encrypted file. Decryption is extremely slow as it is implemented in native Python rather than C.

The module defines the following items:

exception zipfile.BadZipfile

The error raised for bad ZIP files (old name: zipfile.error).

exception zipfile.LargeZipFile

The error raised when a ZIP file would require ZIP64 functionality but that has not been enabled.

class zipfile.ZipFile

The class for reading and writing ZIP files. See section ZipFile Objects for constructor details.

class zipfile.PyZipFile

Class for creating ZIP archives containing Python libraries.

class zipfile.ZipInfo([filename[, date_time]])

Class used to represent information about a member of an archive. Instances of this class are returned by the getinfo() and infolist() methods of ZipFile objects. Most users of the zipfile module will not need to create these, but only use those created by this module. filename should be the full name of the archive member, and date_time should be a tuple containing six fields which describe the time of the last modification to the file; the fields are described in section ZipInfo Objects.

zipfile.is_zipfile(filename)

Returns True if filename is a valid ZIP file based on its magic number, otherwise returns False. filename may be a file or file-like object too.

Changed in version 2.7: Support for file and file-like objects.

zipfile.ZIP_STORED

The numeric constant for an uncompressed archive member.

zipfile.ZIP_DEFLATED

The numeric constant for the usual ZIP compression method. This requires the zlib module. No other compression methods are currently supported.

See also
- PKZIP Application Note Documentation on the ZIP file format by Phil Katz, the creator of the format and algorithms used.
- Info-ZIP Home Page
Information about the Info-ZIP project’s ZIP archive programs and development libraries.

ZipFile Objects

class zipfile.ZipFile(file[, mode[, compression[, allowZip64]]])

Open a ZIP file, where file can be either a path to a file (a string) or a file-like object. The mode parameter should be ‘r’ to read an existing file, ‘w’ to truncate and write a new file, or ‘a’ to append to an existing file. If mode is ‘a’ and file refers to an existing ZIP file, then additional files are added to it. If file does not refer to a ZIP file, then a new ZIP archive is appended to the file. This is meant for adding a ZIP archive to another file (such as python.exe).

Changed in version 2.6: If mode is a and the file does not exist at all, it is created.

compression is the ZIP compression method to use when writing the archive, and should be ZIP_STORED or ZIP_DEFLATED; unrecognized values will cause RuntimeError to be raised. If ZIP_\DEFLATED is specified but the zlib module is not available, RuntimeError is also raised. The default is ZIP_STORED. If allowZip64 is True zipfile will create ZIP files that use the ZIP64 extensions when the zipfile is larger than 2 GB. If it is false (the default) zipfile will raise an exception when the ZIP file would require ZIP64 extensions. ZIP64 extensions are disabled by default because the default zip and unzip commands on Unix (the InfoZIP utilities) don’t support these extensions.

Changed in version 2.7.1: If the file is created with mode ‘a’ or ‘w’ and then closed without adding any files to the archive, the appropriate ZIP structures for an empty archive will be written to the file.

ZipFile is also a context manager and therefore supports the with statement. In the example, myzip is closed after the with statement’s suite is finished—even if an exception occurs:

with ZipFile('spam.zip', 'w') as myzip:
    myzip.write('eggs.txt')

New in version 2.7: Added the ability to use ZipFile as a context manager.

ZipFile.close()

Close the archive file. You must call close() before exiting your program or essential records will not be written.

ZipFile.getinfo(name)

Return a ZipInfo object with information about the archive member name. Calling getinfo() for a name not currently contained in the archive will raise a KeyError.

ZipFile.infolist()

Return a list containing a ZipInfo object for each member of the archive. The objects are in the same order as their entries in the actual ZIP file on disk if an existing archive was opened.

ZipFile.namelist()

Return a list of archive members by name.

ZipFile.open(name[, mode[, pwd]])

Extract a member from the archive as a file-like object (ZipExtFile). name is the name of the file in the archive, or a ZipInfo object. The mode parameter, if included, must be one of the following: ‘r’ (the default), ‘U’, or ‘rU’. Choosing ‘U’ or ‘rU’ will enable universal newline support in the read-only object. pwd is the password used for encrypted files. Calling open() on a closed ZipFile will raise a RuntimeError.

Note: The file-like object is read-only and provides the following methods: read(), readline(), readlines(), __iter__(), next().

Note: If the ZipFile was created by passing in a file-like object as the first argument to the constructor, then the object returned by open() shares the ZipFile’s file pointer. Under these circumstances, the object returned by open() should not be used after any additional operations are performed on the ZipFile object. If the ZipFile was created by passing in a string (the filename) as the first argument to the constructor, then open() will create a new file object that will be held by the ZipExtFile, allowing it to operate independently of the ZipFile.

Note: The open(), read() and extract() methods can take a filename or a ZipInfo object. You will appreciate this when trying to read a ZIP file that contains members with duplicate names.

New in version 2.6.

ZipFile.extract(member[, path[, pwd]])

Extract a member from the archive to the current working directory; member must be its full name or a ZipInfo object). Its file information is extracted as accurately as possible. path specifies a different directory to extract to. member can be a filename or a ZipInfo object. pwd is the password used for encrypted files.

Returns the normalized path created (a directory or new file).

New in version 2.6.

Note: If a member filename is an absolute path, a drive/UNC sharepoint and leading (back)slashes will be stripped, e.g.: ///foo/bar becomes foo/bar on Unix, and C:\foo\bar becomes foo\bar on Windows. And all “..” components in a member filename will be removed, e.g.: ../../foo../../ba..r becomes foo../ba..r. On Windows illegal characters (:, <, >, |, “, ?, and *) replaced by underscore (_).

ZipFile.extractall([path[, members[, pwd]]])

Extract all members from the archive to the current working directory. path specifies a different directory to extract to. members is optional and must be a subset of the list returned by namelist(). pwd is the password used for encrypted files.

Warning: Never extract archives from untrusted sources without prior inspection. It is possible that files are created outside of path, e.g. members that have absolute filenames starting with “/” or filenames with two dots “..”.

Changed in version 2.7.4: The zipfile module attempts to prevent that. See extract() note.

New in version 2.6.

ZipFile.printdir()

Print a table of contents for the archive to sys.stdout.

ZipFile.setpassword(pwd)

Set pwd as default password to extract encrypted files.

New in version 2.6.

ZipFile.read(name[, pwd])

Return the bytes of the file name in the archive. name is the name of the file in the archive, or a ZipInfo object. The archive must be open for read or append. pwd is the password used for encrypted files and, if specified, it will override the default password set with setpassword(). Calling read() on a closed ZipFile will raise a RuntimeError.

Changed in version 2.6: pwd was added, and name can now be a ZipInfo object.

ZipFile.testzip()

Read all the files in the archive and check their CRC’s and file headers. Return the name of the first bad file, or else return None. Calling testzip() on a closed ZipFile will raise a RuntimeError.

ZipFile.write(filename[, arcname[, compress_type]])

Write the file named filename to the archive, giving it the archive name arcname (by default, this will be the same as filename, but without a drive letter and with leading path separators removed). If given, compress_type overrides the value given for the compression parameter to the constructor for the new entry. The archive must be open with mode ‘w’ or ‘a’ – calling write() on a ZipFile created with mode ‘r’ will raise a RuntimeError. Calling write() on a closed ZipFile will raise a RuntimeError.

Note: There is no official file name encoding for ZIP files. If you have unicode file names, you must convert them to byte strings in your desired encoding before passing them to write(). WinZip interprets all file names as encoded in CP437, also known as DOS Latin.

Note: Archive names should be relative to the archive root, that is, they should not start with a path separator.

Note: If arcname (or filename, if arcname is not given) contains a null byte, the name of the file in the archive will be truncated at the null byte.

ZipFile.writestr(zinfo_or_arcname, bytes[, compress_type])

Write the string bytes to the archive; zinfo_or_arcname is either the file name it will be given in the archive, or a ZipInfo instance. If it’s an instance, at least the filename, date, and time must be given. If it’s a name, the date and time is set to the current date and time. The archive must be opened with mode ‘w’ or ‘a’ – calling writestr() on a ZipFile created with mode ‘r’ will raise a RuntimeError. Calling writestr() on a closed ZipFile will raise a RuntimeError.

If given, compress_type overrides the value given for the compression parameter to the constructor for the new entry, or in the zinfo_or_arcname (if that is a ZipInfo instance).

Note: When passing a ZipInfo instance as the zinfo_or_arcname parameter, the compression method used will be that specified in the compress_type member of the given ZipInfo instance. By default, the ZipInfo constructor sets this member to ZIP_STORED.

Changed in version 2.7: The compress_type argument.

The following data attributes are also available:

ZipFile.debug

The level of debug output to use. This may be set from 0 (the default, no output) to 3 (the most output). Debugging information is written to sys.stdout.

ZipFile.comment

The comment text associated with the ZIP file. If assigning a comment to a ZipFile instance created with mode ‘a’ or ‘w’, this should be a string no longer than 65535 bytes. Comments longer than this will be truncated in the written archive when close() is called.

PyZipFile Objects

The PyZipFile constructor takes the same parameters as the ZipFile constructor. Instances have one method in addition to those of ZipFile objects.

PyZipFile.writepy(pathname[, basename])

Search for files *.py and add the corresponding file to the archive. The corresponding file is a *.pyo file if available, else a *.pyc file, compiling if necessary. If the pathname is a file, the filename must end with .py, and just the (corresponding *.py[co]) file is added at the top level (no path information). If the pathname is a file that does not end with .py, a RuntimeError will be raised. If it is a directory, and the directory is not a package directory, then all the files *.py[co] are added at the top level. If the directory is a package directory, then all *.py[co] are added under the package name as a file path, and if any subdirectories are package directories, all of these are added recursively. basename is intended for internal use only. The writepy() method makes archives with file names like this:

string.pyc                                # Top level name
test/__init__.pyc                         # Package directory
test/test_support.pyc                          # Module test.test_support
test/bogus/__init__.pyc                   # Subpackage directory
test/bogus/myfile.pyc                     # Submodule test.bogus.myfile

ZipInfo Objects

Instances of the ZipInfo class are returned by the getinfo() and infolist() methods of ZipFile objects. Each object stores information about a single member of the ZIP archive.

Instances have the following attributes:

ZipInfo.filename

Name of the file in the archive.

ZipInfo.date_time

The time and date of the last modification to the archive member. This is a tuple of six values:

Note: The ZIP file format does not support timestamps before 1980.

ZipInfo.compress_type

Type of compression for the archive member.

ZipInfo.comment

Comment for the individual archive member.

ZipInfo.extra

Expansion field data. The PKZIP Application Note contains some comments on the internal structure of the data contained in this string.

ZipInfo.create_system

System which created ZIP archive.

ZipInfo.create_version

PKZIP version which created ZIP archive.

ZipInfo.extract_version

PKZIP version needed to extract archive.

ZipInfo.reserved

Must be zero.

ZipInfo.flag_bits

ZIP flag bits.

ZipInfo.volume

Volume number of file header.

ZipInfo.internal_attr

Internal attributes.

ZipInfo.external_attr

External file attributes.

ZipInfo.header_offset

Byte offset to the file header.

ZipInfo.CRC

CRC-32 of the uncompressed file.

ZipInfo.compress_size

Size of the compressed data.

ZipInfo.file_size

Size of the uncompressed file.

Reference

1. zipfile module
2. source code