12.4. "zipfile" — Work with ZIP archives
****************************************

1.6 新版功能.

**Source code:** Lib/zipfile.py

======================================================================

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.

   在 2.7 版更改: 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.

参见:

  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.


12.4.1. 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").

   在 2.6 版更改: 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.

   在 2.7.1 版更改: 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')

   2.7 新版功能: 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".

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

   注解: 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.

   注解: 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.

   2.6 新版功能.

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).

   2.6 新版功能.

   注解: 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.

   警告: 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 "".."".

   在 2.7.4 版更改: The zipfile module attempts to prevent that.  See
   "extract()" note.

   2.6 新版功能.

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.

   2.6 新版功能.

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".

   在 2.6 版更改: *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".

   注解: 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.

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

   注解: 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).

   注解: 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".

   在 2.7 版更改: 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.


12.4.2. 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


12.4.3. 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:

   +---------+----------------------------+
   | Index   | Value                      |
   +=========+============================+
   | "0"     | Year (>= 1980)             |
   +---------+----------------------------+
   | "1"     | Month (one-based)          |
   +---------+----------------------------+
   | "2"     | Day of month (one-based)   |
   +---------+----------------------------+
   | "3"     | Hours (zero-based)         |
   +---------+----------------------------+
   | "4"     | Minutes (zero-based)       |
   +---------+----------------------------+
   | "5"     | Seconds (zero-based)       |
   +---------+----------------------------+

   注解: 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.


12.4.4. Command-Line Interface
==============================

The "zipfile" module provides a simple command-line interface to
interact with ZIP archives.

If you want to create a new ZIP archive, specify its name after the
"-c" option and then list the filename(s) that should be included:

   $ python -m zipfile -c monty.zip spam.txt eggs.txt

Passing a directory is also acceptable:

   $ python -m zipfile -c monty.zip life-of-brian_1979/

If you want to extract a ZIP archive into the specified directory, use
the "-e" option:

   $ python -m zipfile -e monty.zip target-dir/

For a list of the files in a ZIP archive, use the "-l" option:

   $ python -m zipfile -l monty.zip


12.4.4.1. Command-line options
------------------------------

-l <zipfile>

   List files in a zipfile.

-c <zipfile> <source1> ... <sourceN>

   Create zipfile from source files.

-e <zipfile> <output_dir>

   Extract zipfile into target directory.

-t <zipfile>

   Test whether the zipfile is valid or not.
