"zipfile" --- Work with ZIP archives
************************************

**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 GiB 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.

   New in version 3.2.

exception zipfile.BadZipfile

   Alias of "BadZipFile", for compatibility with older Python
   versions.

   Deprecated since version 3.2.

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.Path

   A pathlib-compatible wrapper for zip files. See section Path
   Objects for details.

   New in version 3.8.

class zipfile.PyZipFile

   Class for creating ZIP archives containing Python libraries.

class zipfile.ZipInfo(filename='NoName', date_time=(1980, 1, 1, 0, 0, 0))

   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 3.1: 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.

zipfile.ZIP_BZIP2

   The numeric constant for the BZIP2 compression method.  This
   requires the "bz2" module.

   New in version 3.3.

zipfile.ZIP_LZMA

   The numeric constant for the LZMA compression method.  This
   requires the "lzma" module.

   New in version 3.3.

   Note:

     The ZIP file format specification has included support for bzip2
     compression since 2001, and for LZMA compression since 2006.
     However, some tools (including older Python releases) do not
     support these compression methods, and may either refuse to
     process the ZIP file altogether, or fail to extract individual
     files.

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='r', compression=ZIP_STORED, allowZip64=True, compresslevel=None, *, strict_timestamps=True, metadata_encoding=None)

   Open a ZIP file, where *file* can be a path to a file (a string), a
   file-like object or a *path-like object*.

   The *mode* parameter should be "'r'" to read an existing file,
   "'w'" to truncate and write a new file, "'a'" to append to an
   existing file, or "'x'" to exclusively create and write a new file.
   If *mode* is "'x'" and *file* refers to an existing file, a
   "FileExistsError" will be raised. 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").  If *mode* is "'a'" and the
   file does not exist at all, it is created. If *mode* is "'r'" or
   "'a'", the file should be seekable.

   *compression* is the ZIP compression method to use when writing the
   archive, and should be "ZIP_STORED", "ZIP_DEFLATED", "ZIP_BZIP2" or
   "ZIP_LZMA"; unrecognized values will cause "NotImplementedError" to
   be raised.  If "ZIP_DEFLATED", "ZIP_BZIP2" or "ZIP_LZMA" is
   specified but the corresponding module ("zlib", "bz2" or "lzma") is
   not available, "RuntimeError" is raised. The default is
   "ZIP_STORED".

   If *allowZip64* is "True" (the default) zipfile will create ZIP
   files that use the ZIP64 extensions when the zipfile is larger than
   4 GiB. If it is "false" "zipfile" will raise an exception when the
   ZIP file would require ZIP64 extensions.

   The *compresslevel* parameter controls the compression level to use
   when writing files to the archive. When using "ZIP_STORED" or
   "ZIP_LZMA" it has no effect. When using "ZIP_DEFLATED" integers "0"
   through "9" are accepted (see "zlib" for more information). When
   using "ZIP_BZIP2" integers "1" through "9" are accepted (see "bz2"
   for more information).

   The *strict_timestamps* argument, when set to "False", allows to
   zip files older than 1980-01-01 at the cost of setting the
   timestamp to 1980-01-01. Similar behavior occurs with files newer
   than 2107-12-31, the timestamp is also set to the limit.

   When mode is "'r'", *metadata_encoding* may be set to the name of a
   codec, which will be used to decode metadata such as the names of
   members and ZIP comments.

   If the file is created with mode "'w'", "'x'" or "'a'" 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')

   Note:

     *metadata_encoding* is an instance-wide setting for the ZipFile.
     It is not currently possible to set this on a per-member
     basis.This attribute is a workaround for legacy implementations
     which produce archives with names in the current locale encoding
     or code page (mostly on Windows).  According to the .ZIP
     standard, the encoding of metadata may be specified to be either
     IBM code page (default) or UTF-8 by a flag in the archive header.
     That flag takes precedence over *metadata_encoding*, which is a
     Python-specific extension.

   New in version 3.2: Added the ability to use "ZipFile" as a context
   manager.

   Changed in version 3.3: Added support for "bzip2" and "lzma"
   compression.

   Changed in version 3.4: ZIP64 extensions are enabled by default.

   Changed in version 3.5: Added support for writing to unseekable
   streams. Added support for the "'x'" mode.

   Changed in version 3.6: Previously, a plain "RuntimeError" was
   raised for unrecognized compression values.

   Changed in version 3.6.2: The *file* parameter accepts a *path-like
   object*.

   Changed in version 3.7: Add the *compresslevel* parameter.

   New in version 3.8: The *strict_timestamps* keyword-only argument

   Changed in version 3.11: Added support for specifying member name
   encoding for reading metadata in the zipfile's directory and file
   headers.

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='r', pwd=None, *, force_zip64=False)

   Access a member of the archive as a binary file-like object.
   *name* can be either the name of a file within the archive or a
   "ZipInfo" object.  The *mode* parameter, if included, must be "'r'"
   (the default) or "'w'".  *pwd* is the password used to decrypt
   encrypted ZIP files.

   "open()" is also a context manager and therefore supports the
   "with" statement:

      with ZipFile('spam.zip') as myzip:
          with myzip.open('eggs.txt') as myfile:
              print(myfile.read())

   With *mode* "'r'" the file-like object ("ZipExtFile") is read-only
   and provides the following methods: "read()", "readline()",
   "readlines()", "seek()", "tell()", "__iter__()", "__next__()".
   These objects can operate independently of the ZipFile.

   With "mode='w'", a writable file handle is returned, which supports
   the "write()" method.  While a writable file handle is open,
   attempting to read or write other files in the ZIP file will raise
   a "ValueError".

   When writing a file, if the file size is not known in advance but
   may exceed 2 GiB, pass "force_zip64=True" to ensure that the header
   format is capable of supporting large files.  If the file size is
   known in advance, construct a "ZipInfo" object with "file_size"
   set, and use that as the *name* parameter.

   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.

   Changed in version 3.6: Removed support of "mode='U'".  Use
   "io.TextIOWrapper" for reading compressed text files in *universal
   newlines* mode.

   Changed in version 3.6: "ZipFile.open()" can now be used to write
   files into the archive with the "mode='w'" option.

   Changed in version 3.6: Calling "open()" on a closed ZipFile will
   raise a "ValueError". Previously, a "RuntimeError" was raised.

ZipFile.extract(member, path=None, pwd=None)

   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).

   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 ("_").

   Changed in version 3.6: Calling "extract()" on a closed ZipFile
   will raise a "ValueError".  Previously, a "RuntimeError" was
   raised.

   Changed in version 3.6.2: The *path* parameter accepts a *path-like
   object*.

ZipFile.extractall(path=None, members=None, pwd=None)

   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 "".."".  This module attempts to
     prevent that. See "extract()" note.

   Changed in version 3.6: Calling "extractall()" on a closed ZipFile
   will raise a "ValueError".  Previously, a "RuntimeError" was
   raised.

   Changed in version 3.6.2: The *path* parameter accepts a *path-like
   object*.

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.

ZipFile.read(name, pwd=None)

   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
   ZipFile that uses a compression method other than "ZIP_STORED",
   "ZIP_DEFLATED", "ZIP_BZIP2" or "ZIP_LZMA" will raise a
   "NotImplementedError". An error will also be raised if the
   corresponding compression module is not available.

   Changed in version 3.6: Calling "read()" on a closed ZipFile will
   raise a "ValueError". Previously, a "RuntimeError" was raised.

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".

   Changed in version 3.6: Calling "testzip()" on a closed ZipFile
   will raise a "ValueError".  Previously, a "RuntimeError" was
   raised.

ZipFile.write(filename, arcname=None, compress_type=None, compresslevel=None)

   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. Similarly, *compresslevel* will override the constructor
   if given. The archive must be open with mode "'w'", "'x'" or "'a'".

   Note:

     The ZIP file standard historically did not specify a metadata
     encoding, but strongly recommended CP437 (the original IBM PC
     encoding) for interoperability.  Recent versions allow use of
     UTF-8 (only).  In this module, UTF-8 will automatically be used
     to write the member names if they contain any non-ASCII
     characters.  It is not possible to write member names in any
     encoding other than ASCII or UTF-8.

   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.

   Note:

     A leading slash in the filename may lead to the archive being
     impossible to open in some zip programs on Windows systems.

   Changed in version 3.6: Calling "write()" on a ZipFile created with
   mode "'r'" or a closed ZipFile will raise a "ValueError".
   Previously, a "RuntimeError" was raised.

ZipFile.writestr(zinfo_or_arcname, data, compress_type=None, compresslevel=None)

   Write a file into the archive.  The contents is *data*, which may
   be either a "str" or a "bytes" instance; if it is a "str", it is
   encoded as UTF-8 first.  *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'", "'x'" or "'a'".

   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).
   Similarly, *compresslevel* will override the constructor if given.

   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 3.2: The *compress_type* argument.

   Changed in version 3.6: Calling "writestr()" on a ZipFile created
   with mode "'r'" or a closed ZipFile will raise a "ValueError".
   Previously, a "RuntimeError" was raised.

ZipFile.mkdir(zinfo_or_directory, mode=511)

   Create a directory inside the archive.  If *zinfo_or_directory* is
   a string, a directory is created inside the archive with the mode
   that is specified in the *mode* argument. If, however,
   *zinfo_or_directory* is a "ZipInfo" instance then the *mode*
   argument is ignored.

   The archive must be opened with mode "'w'", "'x'" or "'a'".

   New in version 3.11.

The following data attributes are also available:

ZipFile.filename

   Name of the ZIP file.

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 associated with the ZIP file as a "bytes" object. If
   assigning a comment to a "ZipFile" instance created with mode
   "'w'", "'x'" or "'a'", it should be no longer than 65535 bytes.
   Comments longer than this will be truncated.


Path Objects
============

class zipfile.Path(root, at='')

   Construct a Path object from a "root" zipfile (which may be a
   "ZipFile" instance or "file" suitable for passing to the "ZipFile"
   constructor).

   "at" specifies the location of this Path within the zipfile, e.g.
   'dir/file.txt', 'dir/', or ''. Defaults to the empty string,
   indicating the root.

Path objects expose the following features of "pathlib.Path" objects:

Path objects are traversable using the "/" operator or "joinpath".

Path.name

   The final path component.

Path.open(mode='r', *, pwd, **)

   Invoke "ZipFile.open()" on the current path. Allows opening for
   read or write, text or binary through supported modes: 'r', 'w',
   'rb', 'wb'. Positional and keyword arguments are passed through to
   "io.TextIOWrapper" when opened as text and ignored otherwise. "pwd"
   is the "pwd" parameter to "ZipFile.open()".

   Changed in version 3.9: Added support for text and binary modes for
   open. Default mode is now text.

Path.iterdir()

   Enumerate the children of the current directory.

Path.is_dir()

   Return "True" if the current context references a directory.

Path.is_file()

   Return "True" if the current context references a file.

Path.exists()

   Return "True" if the current context references a file or directory
   in the zip file.

Path.suffix

   The file extension of the final component.

   New in version 3.11: Added "Path.suffix" property.

Path.stem

   The final path component, without its suffix.

   New in version 3.11: Added "Path.stem" property.

Path.suffixes

   A list of the path’s file extensions.

   New in version 3.11: Added "Path.suffixes" property.

Path.read_text(*, **)

   Read the current file as unicode text. Positional and keyword
   arguments are passed through to "io.TextIOWrapper" (except
   "buffer", which is implied by the context).

Path.read_bytes()

   Read the current file as bytes.

Path.joinpath(*other)

   Return a new Path object with each of the *other* arguments joined.
   The following are equivalent:

      >>> Path(...).joinpath('child').joinpath('grandchild')
      >>> Path(...).joinpath('child', 'grandchild')
      >>> Path(...) / 'child' / 'grandchild'

   Changed in version 3.10: Prior to 3.10, "joinpath" was undocumented
   and accepted exactly one parameter.

The zipp project provides backports of the latest path object
functionality to older Pythons. Use "zipp.Path" in place of
"zipfile.Path" for early access to changes.


PyZipFile Objects
=================

The "PyZipFile" constructor takes the same parameters as the "ZipFile"
constructor, and one additional parameter, *optimize*.

class zipfile.PyZipFile(file, mode='r', compression=ZIP_STORED, allowZip64=True, optimize=- 1)

   New in version 3.2: The *optimize* parameter.

   Changed in version 3.4: ZIP64 extensions are enabled by default.

   Instances have one method in addition to those of "ZipFile"
   objects:

   writepy(pathname, basename='', filterfunc=None)

      Search for files "*.py" and add the corresponding file to the
      archive.

      If the *optimize* parameter to "PyZipFile" was not given or
      "-1", the corresponding file is a "*.pyc" file, compiling if
      necessary.

      If the *optimize* parameter to "PyZipFile" was "0", "1" or "2",
      only files with that optimization level (see "compile()") are
      added to the archive, compiling if necessary.

      If *pathname* is a file, the filename must end with ".py", and
      just the (corresponding "*.pyc") file is added at the top level
      (no path information).  If *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 "*.pyc" are added at the top level.  If the
      directory is a package directory, then all "*.pyc" are added
      under the package name as a file path, and if any subdirectories
      are package directories, all of these are added recursively in
      sorted order.

      *basename* is intended for internal use only.

      *filterfunc*, if given, must be a function taking a single
      string argument.  It will be passed each path (including each
      individual full file path) before it is added to the archive.
      If *filterfunc* returns a false value, the path will not be
      added, and if it is a directory its contents will be ignored.
      For example, if our test files are all either in "test"
      directories or start with the string "test_", we can use a
      *filterfunc* to exclude them:

         >>> zf = PyZipFile('myprog.zip')
         >>> def notests(s):
         ...     fn = os.path.basename(s)
         ...     return (not (fn == 'test' or fn.startswith('test_')))
         >>> zf.writepy('myprog', filterfunc=notests)

      The "writepy()" method makes archives with file names like this:

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

      New in version 3.4: The *filterfunc* parameter.

      Changed in version 3.6.2: The *pathname* parameter accepts a
      *path-like object*.

      Changed in version 3.7: Recursion sorts directory entries.


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.

There is one classmethod to make a "ZipInfo" instance for a filesystem
file:

classmethod ZipInfo.from_file(filename, arcname=None, *, strict_timestamps=True)

   Construct a "ZipInfo" instance for a file on the filesystem, in
   preparation for adding it to a zip file.

   *filename* should be the path to a file or directory on the
   filesystem.

   If *arcname* is specified, it is used as the name within the
   archive. If *arcname* is not specified, the name will be the same
   as *filename*, but with any drive letter and leading path
   separators removed.

   The *strict_timestamps* argument, when set to "False", allows to
   zip files older than 1980-01-01 at the cost of setting the
   timestamp to 1980-01-01. Similar behavior occurs with files newer
   than 2107-12-31, the timestamp is also set to the limit.

   New in version 3.6.

   Changed in version 3.6.2: The *filename* parameter accepts a *path-
   like object*.

   New in version 3.8: The *strict_timestamps* keyword-only argument

Instances have the following methods and attributes:

ZipInfo.is_dir()

   Return "True" if this archive member is a directory.

   This uses the entry's name: directories should always end with "/".

   New in version 3.6.

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)       |
   +---------+----------------------------+

   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 as a "bytes" object.

ZipInfo.extra

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

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.


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


Command-line options
--------------------

-l <zipfile>
--list <zipfile>

   List files in a zipfile.

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

   Create zipfile from source files.

-e <zipfile> <output_dir>
--extract <zipfile> <output_dir>

   Extract zipfile into target directory.

-t <zipfile>
--test <zipfile>

   Test whether the zipfile is valid or not.

--metadata-encoding <encoding>

   Specify encoding of member names for "-l", "-e" and "-t".

   New in version 3.11.


Decompression pitfalls
======================

The extraction in zipfile module might fail due to some pitfalls
listed below.


From file itself
----------------

Decompression may fail due to incorrect password / CRC checksum / ZIP
format or unsupported compression method / decryption.


File System limitations
-----------------------

Exceeding limitations on different file systems can cause
decompression failed. Such as allowable characters in the directory
entries, length of the file name, length of the pathname, size of a
single file, and number of files, etc.


Resources limitations
---------------------

The lack of memory or disk volume would lead to decompression failed.
For example, decompression bombs (aka ZIP bomb) apply to zipfile
library that can cause disk volume exhaustion.


Interruption
------------

Interruption during the decompression, such as pressing control-C or
killing the decompression process may result in incomplete
decompression of the archive.


Default behaviors of extraction
-------------------------------

Not knowing the default extraction behaviors can cause unexpected
decompression results. For example, when extracting the same archive
twice, it overwrites files without asking.
