数据压缩和归档(二)、zipfile

参考 数据压缩和归档(二)、zipfile - 云+社区 - 腾讯云

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.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.

ZipFile Objects

class zipfile.ZipFile(file, mode='r', compression=ZIP_STORED, allowZip64=True, compresslevel=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).

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')

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.

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: 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

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.

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.

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.

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)

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.

New in version 3.6.

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

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.