cpython/Doc/library/gzip.rst

283 lines
10 KiB
ReStructuredText
Raw Normal View History

2007-08-15 11:28:22 -03:00
:mod:`gzip` --- Support for :program:`gzip` files
=================================================
.. module:: gzip
:synopsis: Interfaces for gzip compression and decompression using file objects.
2011-01-27 16:38:46 -04:00
**Source code:** :source:`Lib/gzip.py`
--------------
Merged revisions 61981,61984-61987,61992-61993,61997-62000 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r61981 | amaury.forgeotdarc | 2008-03-28 01:21:34 +0100 (Fri, 28 Mar 2008) | 2 lines test_future3.py is a regular test file, and should be part of the test suite ........ r61984 | jeffrey.yasskin | 2008-03-28 05:11:18 +0100 (Fri, 28 Mar 2008) | 6 lines Kill a race in test_threading in which the exception info in a thread finishing up after it was joined had a traceback pointing to that thread's (deleted) target attribute, while the test was trying to check that the target was destroyed. Big thanks to Antoine Pitrou for diagnosing the race and pointing out sys.exc_clear() to kill the exception early. This fixes issue 2496. ........ r61985 | neal.norwitz | 2008-03-28 05:41:34 +0100 (Fri, 28 Mar 2008) | 1 line Allow use of other ports so the test can pass if 9091 is in use ........ r61986 | jeffrey.yasskin | 2008-03-28 05:53:10 +0100 (Fri, 28 Mar 2008) | 2 lines Print more information the next time test_socket throws the wrong exception. ........ r61987 | neal.norwitz | 2008-03-28 05:58:51 +0100 (Fri, 28 Mar 2008) | 5 lines Revert r61969 which added casts to Py_CHARMASK to avoid compiler warnings. Rather than sprinkle casts throughout the code, change Py_CHARMASK to always cast it's result to an unsigned char. This should ensure we do the right thing when accessing an array with the result. ........ r61992 | neal.norwitz | 2008-03-28 06:34:59 +0100 (Fri, 28 Mar 2008) | 2 lines Fix compiler warning about finite() missing on Solaris. ........ r61993 | neal.norwitz | 2008-03-28 07:34:03 +0100 (Fri, 28 Mar 2008) | 11 lines Bug 1503: Get the test to pass on OSX. This should make the test more reliable, but I'm not convinced it is the right solution. We need to determine if this causes the test to hang on any platforms or do other bad things. Even if it gets the test to pass reliably, it might be that we want to fix this in socket. The socket returned from accept() is different on different platforms (inheriting attributes or not) and we might want to ensure that the attributes (at least blocking) is the same across all platforms. ........ r61997 | neal.norwitz | 2008-03-28 08:36:31 +0100 (Fri, 28 Mar 2008) | 1 line Name the main method correctly so the test is run ........ r61998 | gregory.p.smith | 2008-03-28 09:00:44 +0100 (Fri, 28 Mar 2008) | 7 lines This patch moves some tests from test_urllib2_net to test_urllib2_localnet. The moved tests use a local server rather than going out to external servers. Accepts patch from issue2429. Contributed by Jerry Seutter & Michael Foord (fuzzyman) at PyCon 2008. ........ r61999 | georg.brandl | 2008-03-28 09:06:56 +0100 (Fri, 28 Mar 2008) | 2 lines #2406: add examples to gzip docs. ........ r62000 | gregory.p.smith | 2008-03-28 09:32:09 +0100 (Fri, 28 Mar 2008) | 4 lines Accept patch issue2426 by Paul Kippes (kippesp). Adds sqlite3.Connection.iterdump to allow dumping of databases. ........
2008-03-28 07:53:29 -03:00
This module provides a simple interface to compress and decompress files just
like the GNU programs :program:`gzip` and :program:`gunzip` would.
The data compression is provided by the :mod:`zlib` module.
2007-08-15 11:28:22 -03:00
The :mod:`gzip` module provides the :class:`GzipFile` class, as well as the
2012-06-04 18:21:38 -03:00
:func:`.open`, :func:`compress` and :func:`decompress` convenience functions.
The :class:`GzipFile` class reads and writes :program:`gzip`\ -format files,
automatically compressing or decompressing the data so that it looks like an
ordinary :term:`file object`.
Merged revisions 61981,61984-61987,61992-61993,61997-62000 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r61981 | amaury.forgeotdarc | 2008-03-28 01:21:34 +0100 (Fri, 28 Mar 2008) | 2 lines test_future3.py is a regular test file, and should be part of the test suite ........ r61984 | jeffrey.yasskin | 2008-03-28 05:11:18 +0100 (Fri, 28 Mar 2008) | 6 lines Kill a race in test_threading in which the exception info in a thread finishing up after it was joined had a traceback pointing to that thread's (deleted) target attribute, while the test was trying to check that the target was destroyed. Big thanks to Antoine Pitrou for diagnosing the race and pointing out sys.exc_clear() to kill the exception early. This fixes issue 2496. ........ r61985 | neal.norwitz | 2008-03-28 05:41:34 +0100 (Fri, 28 Mar 2008) | 1 line Allow use of other ports so the test can pass if 9091 is in use ........ r61986 | jeffrey.yasskin | 2008-03-28 05:53:10 +0100 (Fri, 28 Mar 2008) | 2 lines Print more information the next time test_socket throws the wrong exception. ........ r61987 | neal.norwitz | 2008-03-28 05:58:51 +0100 (Fri, 28 Mar 2008) | 5 lines Revert r61969 which added casts to Py_CHARMASK to avoid compiler warnings. Rather than sprinkle casts throughout the code, change Py_CHARMASK to always cast it's result to an unsigned char. This should ensure we do the right thing when accessing an array with the result. ........ r61992 | neal.norwitz | 2008-03-28 06:34:59 +0100 (Fri, 28 Mar 2008) | 2 lines Fix compiler warning about finite() missing on Solaris. ........ r61993 | neal.norwitz | 2008-03-28 07:34:03 +0100 (Fri, 28 Mar 2008) | 11 lines Bug 1503: Get the test to pass on OSX. This should make the test more reliable, but I'm not convinced it is the right solution. We need to determine if this causes the test to hang on any platforms or do other bad things. Even if it gets the test to pass reliably, it might be that we want to fix this in socket. The socket returned from accept() is different on different platforms (inheriting attributes or not) and we might want to ensure that the attributes (at least blocking) is the same across all platforms. ........ r61997 | neal.norwitz | 2008-03-28 08:36:31 +0100 (Fri, 28 Mar 2008) | 1 line Name the main method correctly so the test is run ........ r61998 | gregory.p.smith | 2008-03-28 09:00:44 +0100 (Fri, 28 Mar 2008) | 7 lines This patch moves some tests from test_urllib2_net to test_urllib2_localnet. The moved tests use a local server rather than going out to external servers. Accepts patch from issue2429. Contributed by Jerry Seutter & Michael Foord (fuzzyman) at PyCon 2008. ........ r61999 | georg.brandl | 2008-03-28 09:06:56 +0100 (Fri, 28 Mar 2008) | 2 lines #2406: add examples to gzip docs. ........ r62000 | gregory.p.smith | 2008-03-28 09:32:09 +0100 (Fri, 28 Mar 2008) | 4 lines Accept patch issue2426 by Paul Kippes (kippesp). Adds sqlite3.Connection.iterdump to allow dumping of databases. ........
2008-03-28 07:53:29 -03:00
Note that additional file formats which can be decompressed by the
:program:`gzip` and :program:`gunzip` programs, such as those produced by
:program:`compress` and :program:`pack`, are not supported by this module.
2007-08-15 11:28:22 -03:00
The module defines the following items:
.. function:: open(filename, mode='rb', compresslevel=9, encoding=None, errors=None, newline=None)
2012-06-04 18:21:38 -03:00
Open a gzip-compressed file in binary or text mode, returning a :term:`file
object`.
2012-06-04 18:21:38 -03:00
The *filename* argument can be an actual filename (a :class:`str` or
:class:`bytes` object), or an existing file object to read from or write to.
The *mode* argument can be any of ``'r'``, ``'rb'``, ``'a'``, ``'ab'``,
``'w'``, ``'wb'``, ``'x'`` or ``'xb'`` for binary mode, or ``'rt'``,
``'at'``, ``'wt'``, or ``'xt'`` for text mode. The default is ``'rb'``.
The *compresslevel* argument is an integer from 0 to 9, as for the
:class:`GzipFile` constructor.
For binary mode, this function is equivalent to the :class:`GzipFile`
constructor: ``GzipFile(filename, mode, compresslevel)``. In this case, the
*encoding*, *errors* and *newline* arguments must not be provided.
For text mode, a :class:`GzipFile` object is created, and wrapped in an
:class:`io.TextIOWrapper` instance with the specified encoding, error
handling behavior, and line ending(s).
.. versionchanged:: 3.3
2012-06-04 18:21:38 -03:00
Added support for *filename* being a file object, support for text mode,
and the *encoding*, *errors* and *newline* arguments.
.. versionchanged:: 3.4
Added support for the ``'x'``, ``'xb'`` and ``'xt'`` modes.
.. versionchanged:: 3.6
Accepts a :term:`path-like object`.
.. exception:: BadGzipFile
An exception raised for invalid gzip files. It inherits :exc:`OSError`.
:exc:`EOFError` and :exc:`zlib.error` can also be raised for invalid gzip
files.
.. versionadded:: 3.8
.. class:: GzipFile(filename=None, mode=None, compresslevel=9, fileobj=None, mtime=None)
2007-08-15 11:28:22 -03:00
Constructor for the :class:`GzipFile` class, which simulates most of the
methods of a :term:`file object`, with the exception of the :meth:`truncate`
method. At least one of *fileobj* and *filename* must be given a non-trivial
value.
2007-08-15 11:28:22 -03:00
The new class instance is based on *fileobj*, which can be a regular file, an
:class:`io.BytesIO` object, or any other object which simulates a file. It
2007-08-15 11:28:22 -03:00
defaults to ``None``, in which case *filename* is opened to provide a file
object.
When *fileobj* is not ``None``, the *filename* argument is only used to be
2013-10-06 07:33:20 -03:00
included in the :program:`gzip` file header, which may include the original
2007-08-15 11:28:22 -03:00
filename of the uncompressed file. It defaults to the filename of *fileobj*, if
discernible; otherwise, it defaults to the empty string, and in this case the
original filename is not included in the header.
The *mode* argument can be any of ``'r'``, ``'rb'``, ``'a'``, ``'ab'``, ``'w'``,
``'wb'``, ``'x'``, or ``'xb'``, depending on whether the file will be read or
written. The default is the mode of *fileobj* if discernible; otherwise, the
default is ``'rb'``. In future Python releases the mode of *fileobj* will
not be used. It is better to always specify *mode* for writing.
Note that the file is always opened in binary mode. To open a compressed file
2012-06-04 18:21:38 -03:00
in text mode, use :func:`.open` (or wrap your :class:`GzipFile` with an
:class:`io.TextIOWrapper`).
2007-08-15 11:28:22 -03:00
The *compresslevel* argument is an integer from ``0`` to ``9`` controlling
the level of compression; ``1`` is fastest and produces the least
compression, and ``9`` is slowest and produces the most compression. ``0``
is no compression. The default is ``9``.
2007-08-15 11:28:22 -03:00
The *mtime* argument is an optional numeric timestamp to be written to
the last modification time field in the stream when compressing. It
should only be provided in compression mode. If omitted or ``None``, the
current time is used. See the :attr:`mtime` attribute for more details.
2007-08-15 11:28:22 -03:00
Calling a :class:`GzipFile` object's :meth:`close` method does not close
*fileobj*, since you might wish to append more material after the compressed
data. This also allows you to pass an :class:`io.BytesIO` object opened for
2007-08-15 11:28:22 -03:00
writing as *fileobj*, and retrieve the resulting memory buffer using the
2010-09-23 13:45:17 -03:00
:class:`io.BytesIO` object's :meth:`~io.BytesIO.getvalue` method.
2007-08-15 11:28:22 -03:00
:class:`GzipFile` supports the :class:`io.BufferedIOBase` interface,
including iteration and the :keyword:`with` statement. Only the
:meth:`truncate` method isn't implemented.
Merged revisions 69998-69999,70002,70022-70023,70025-70026,70061,70086,70145,70171,70183,70188,70235,70244,70275,70281 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r69998 | benjamin.peterson | 2009-02-26 13:04:40 -0600 (Thu, 26 Feb 2009) | 1 line the startship is rather outdated now ........ r69999 | benjamin.peterson | 2009-02-26 13:05:59 -0600 (Thu, 26 Feb 2009) | 1 line comma ........ r70002 | andrew.kuchling | 2009-02-26 16:34:30 -0600 (Thu, 26 Feb 2009) | 1 line The curses panel library is now supported ........ r70022 | georg.brandl | 2009-02-27 10:23:18 -0600 (Fri, 27 Feb 2009) | 1 line #5361: fix typo. ........ r70023 | georg.brandl | 2009-02-27 10:39:26 -0600 (Fri, 27 Feb 2009) | 1 line #5363: fix cmpfiles() docs. Another instance where a prose description is twice as long as the code. ........ r70025 | georg.brandl | 2009-02-27 10:52:55 -0600 (Fri, 27 Feb 2009) | 1 line #5344: fix punctuation. ........ r70026 | georg.brandl | 2009-02-27 10:59:03 -0600 (Fri, 27 Feb 2009) | 1 line #5365: add quick look conversion table for different time representations. ........ r70061 | hirokazu.yamamoto | 2009-02-28 09:24:00 -0600 (Sat, 28 Feb 2009) | 1 line Binary flag is needed on windows. ........ r70086 | benjamin.peterson | 2009-03-01 21:35:12 -0600 (Sun, 01 Mar 2009) | 1 line fix a silly problem of caching gone wrong #5401 ........ r70145 | benjamin.peterson | 2009-03-03 16:51:57 -0600 (Tue, 03 Mar 2009) | 1 line making the writing more formal ........ r70171 | facundo.batista | 2009-03-04 15:18:17 -0600 (Wed, 04 Mar 2009) | 3 lines Fixed a typo. ........ r70183 | benjamin.peterson | 2009-03-04 18:17:57 -0600 (Wed, 04 Mar 2009) | 1 line add example ........ r70188 | hirokazu.yamamoto | 2009-03-05 03:34:14 -0600 (Thu, 05 Mar 2009) | 1 line Fixed memory leak on failure. ........ r70235 | benjamin.peterson | 2009-03-07 18:21:17 -0600 (Sat, 07 Mar 2009) | 1 line fix funky indentation ........ r70244 | martin.v.loewis | 2009-03-08 09:06:19 -0500 (Sun, 08 Mar 2009) | 2 lines Add Chris Withers. ........ r70275 | georg.brandl | 2009-03-09 11:35:48 -0500 (Mon, 09 Mar 2009) | 2 lines Add missing space. ........ r70281 | benjamin.peterson | 2009-03-09 15:38:56 -0500 (Mon, 09 Mar 2009) | 1 line gzip and bz2 are context managers ........
2009-03-09 18:04:33 -03:00
:class:`GzipFile` also provides the following method and attribute:
.. method:: peek(n)
Read *n* uncompressed bytes without advancing the file position.
At most one single read on the compressed stream is done to satisfy
the call. The number of bytes returned may be more or less than
requested.
.. note:: While calling :meth:`peek` does not change the file position of
the :class:`GzipFile`, it may change the position of the underlying
file object (e.g. if the :class:`GzipFile` was constructed with the
*fileobj* parameter).
.. versionadded:: 3.2
.. attribute:: mtime
When decompressing, the value of the last modification time field in
the most recently read header may be read from this attribute, as an
integer. The initial value before reading any headers is ``None``.
All :program:`gzip` compressed streams are required to contain this
timestamp field. Some programs, such as :program:`gunzip`\ , make use
of the timestamp. The format is the same as the return value of
:func:`time.time` and the :attr:`~os.stat_result.st_mtime` attribute of
the object returned by :func:`os.stat`.
2009-03-09 18:08:47 -03:00
.. versionchanged:: 3.1
Support for the :keyword:`with` statement was added, along with the
*mtime* constructor argument and :attr:`mtime` attribute.
Merged revisions 69998-69999,70002,70022-70023,70025-70026,70061,70086,70145,70171,70183,70188,70235,70244,70275,70281 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r69998 | benjamin.peterson | 2009-02-26 13:04:40 -0600 (Thu, 26 Feb 2009) | 1 line the startship is rather outdated now ........ r69999 | benjamin.peterson | 2009-02-26 13:05:59 -0600 (Thu, 26 Feb 2009) | 1 line comma ........ r70002 | andrew.kuchling | 2009-02-26 16:34:30 -0600 (Thu, 26 Feb 2009) | 1 line The curses panel library is now supported ........ r70022 | georg.brandl | 2009-02-27 10:23:18 -0600 (Fri, 27 Feb 2009) | 1 line #5361: fix typo. ........ r70023 | georg.brandl | 2009-02-27 10:39:26 -0600 (Fri, 27 Feb 2009) | 1 line #5363: fix cmpfiles() docs. Another instance where a prose description is twice as long as the code. ........ r70025 | georg.brandl | 2009-02-27 10:52:55 -0600 (Fri, 27 Feb 2009) | 1 line #5344: fix punctuation. ........ r70026 | georg.brandl | 2009-02-27 10:59:03 -0600 (Fri, 27 Feb 2009) | 1 line #5365: add quick look conversion table for different time representations. ........ r70061 | hirokazu.yamamoto | 2009-02-28 09:24:00 -0600 (Sat, 28 Feb 2009) | 1 line Binary flag is needed on windows. ........ r70086 | benjamin.peterson | 2009-03-01 21:35:12 -0600 (Sun, 01 Mar 2009) | 1 line fix a silly problem of caching gone wrong #5401 ........ r70145 | benjamin.peterson | 2009-03-03 16:51:57 -0600 (Tue, 03 Mar 2009) | 1 line making the writing more formal ........ r70171 | facundo.batista | 2009-03-04 15:18:17 -0600 (Wed, 04 Mar 2009) | 3 lines Fixed a typo. ........ r70183 | benjamin.peterson | 2009-03-04 18:17:57 -0600 (Wed, 04 Mar 2009) | 1 line add example ........ r70188 | hirokazu.yamamoto | 2009-03-05 03:34:14 -0600 (Thu, 05 Mar 2009) | 1 line Fixed memory leak on failure. ........ r70235 | benjamin.peterson | 2009-03-07 18:21:17 -0600 (Sat, 07 Mar 2009) | 1 line fix funky indentation ........ r70244 | martin.v.loewis | 2009-03-08 09:06:19 -0500 (Sun, 08 Mar 2009) | 2 lines Add Chris Withers. ........ r70275 | georg.brandl | 2009-03-09 11:35:48 -0500 (Mon, 09 Mar 2009) | 2 lines Add missing space. ........ r70281 | benjamin.peterson | 2009-03-09 15:38:56 -0500 (Mon, 09 Mar 2009) | 1 line gzip and bz2 are context managers ........
2009-03-09 18:04:33 -03:00
.. versionchanged:: 3.2
Support for zero-padded and unseekable files was added.
.. versionchanged:: 3.3
The :meth:`io.BufferedIOBase.read1` method is now implemented.
.. versionchanged:: 3.4
Added support for the ``'x'`` and ``'xb'`` modes.
.. versionchanged:: 3.5
Added support for writing arbitrary
:term:`bytes-like objects <bytes-like object>`.
The :meth:`~io.BufferedIOBase.read` method now accepts an argument of
``None``.
.. versionchanged:: 3.6
Accepts a :term:`path-like object`.
.. versionchanged:: 3.12
Remove the ``filename`` attribute, use the :attr:`~GzipFile.name`
attribute instead.
.. deprecated:: 3.9
Opening :class:`GzipFile` for writing without specifying the *mode*
argument is deprecated.
2007-08-15 11:28:22 -03:00
.. function:: compress(data, compresslevel=9, *, mtime=None)
Compress the *data*, returning a :class:`bytes` object containing
the compressed data. *compresslevel* and *mtime* have the same meaning as in
the :class:`GzipFile` constructor above. When *mtime* is set to ``0``, this
function is equivalent to :func:`zlib.compress` with *wbits* set to ``31``.
The zlib function is faster.
2010-08-17 18:15:00 -03:00
.. versionadded:: 3.2
.. versionchanged:: 3.8
Added the *mtime* parameter for reproducible output.
.. versionchanged:: 3.11
Speed is improved by compressing all data at once instead of in a
streamed fashion. Calls with *mtime* set to ``0`` are delegated to
:func:`zlib.compress` for better speed.
2010-08-17 18:15:00 -03:00
.. function:: decompress(data)
Decompress the *data*, returning a :class:`bytes` object containing the
uncompressed data. This function is capable of decompressing multi-member
gzip data (multiple gzip blocks concatenated together). When the data is
certain to contain only one member the :func:`zlib.decompress` function with
*wbits* set to 31 is faster.
2010-08-17 18:15:00 -03:00
.. versionadded:: 3.2
.. versionchanged:: 3.11
Speed is improved by decompressing members at once in memory instead of in
a streamed fashion.
2007-08-15 11:28:22 -03:00
Merged revisions 61981,61984-61987,61992-61993,61997-62000 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r61981 | amaury.forgeotdarc | 2008-03-28 01:21:34 +0100 (Fri, 28 Mar 2008) | 2 lines test_future3.py is a regular test file, and should be part of the test suite ........ r61984 | jeffrey.yasskin | 2008-03-28 05:11:18 +0100 (Fri, 28 Mar 2008) | 6 lines Kill a race in test_threading in which the exception info in a thread finishing up after it was joined had a traceback pointing to that thread's (deleted) target attribute, while the test was trying to check that the target was destroyed. Big thanks to Antoine Pitrou for diagnosing the race and pointing out sys.exc_clear() to kill the exception early. This fixes issue 2496. ........ r61985 | neal.norwitz | 2008-03-28 05:41:34 +0100 (Fri, 28 Mar 2008) | 1 line Allow use of other ports so the test can pass if 9091 is in use ........ r61986 | jeffrey.yasskin | 2008-03-28 05:53:10 +0100 (Fri, 28 Mar 2008) | 2 lines Print more information the next time test_socket throws the wrong exception. ........ r61987 | neal.norwitz | 2008-03-28 05:58:51 +0100 (Fri, 28 Mar 2008) | 5 lines Revert r61969 which added casts to Py_CHARMASK to avoid compiler warnings. Rather than sprinkle casts throughout the code, change Py_CHARMASK to always cast it's result to an unsigned char. This should ensure we do the right thing when accessing an array with the result. ........ r61992 | neal.norwitz | 2008-03-28 06:34:59 +0100 (Fri, 28 Mar 2008) | 2 lines Fix compiler warning about finite() missing on Solaris. ........ r61993 | neal.norwitz | 2008-03-28 07:34:03 +0100 (Fri, 28 Mar 2008) | 11 lines Bug 1503: Get the test to pass on OSX. This should make the test more reliable, but I'm not convinced it is the right solution. We need to determine if this causes the test to hang on any platforms or do other bad things. Even if it gets the test to pass reliably, it might be that we want to fix this in socket. The socket returned from accept() is different on different platforms (inheriting attributes or not) and we might want to ensure that the attributes (at least blocking) is the same across all platforms. ........ r61997 | neal.norwitz | 2008-03-28 08:36:31 +0100 (Fri, 28 Mar 2008) | 1 line Name the main method correctly so the test is run ........ r61998 | gregory.p.smith | 2008-03-28 09:00:44 +0100 (Fri, 28 Mar 2008) | 7 lines This patch moves some tests from test_urllib2_net to test_urllib2_localnet. The moved tests use a local server rather than going out to external servers. Accepts patch from issue2429. Contributed by Jerry Seutter & Michael Foord (fuzzyman) at PyCon 2008. ........ r61999 | georg.brandl | 2008-03-28 09:06:56 +0100 (Fri, 28 Mar 2008) | 2 lines #2406: add examples to gzip docs. ........ r62000 | gregory.p.smith | 2008-03-28 09:32:09 +0100 (Fri, 28 Mar 2008) | 4 lines Accept patch issue2426 by Paul Kippes (kippesp). Adds sqlite3.Connection.iterdump to allow dumping of databases. ........
2008-03-28 07:53:29 -03:00
.. _gzip-usage-examples:
Examples of usage
-----------------
Example of how to read a compressed file::
import gzip
2010-08-17 18:11:49 -03:00
with gzip.open('/home/joe/file.txt.gz', 'rb') as f:
file_content = f.read()
Merged revisions 61981,61984-61987,61992-61993,61997-62000 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r61981 | amaury.forgeotdarc | 2008-03-28 01:21:34 +0100 (Fri, 28 Mar 2008) | 2 lines test_future3.py is a regular test file, and should be part of the test suite ........ r61984 | jeffrey.yasskin | 2008-03-28 05:11:18 +0100 (Fri, 28 Mar 2008) | 6 lines Kill a race in test_threading in which the exception info in a thread finishing up after it was joined had a traceback pointing to that thread's (deleted) target attribute, while the test was trying to check that the target was destroyed. Big thanks to Antoine Pitrou for diagnosing the race and pointing out sys.exc_clear() to kill the exception early. This fixes issue 2496. ........ r61985 | neal.norwitz | 2008-03-28 05:41:34 +0100 (Fri, 28 Mar 2008) | 1 line Allow use of other ports so the test can pass if 9091 is in use ........ r61986 | jeffrey.yasskin | 2008-03-28 05:53:10 +0100 (Fri, 28 Mar 2008) | 2 lines Print more information the next time test_socket throws the wrong exception. ........ r61987 | neal.norwitz | 2008-03-28 05:58:51 +0100 (Fri, 28 Mar 2008) | 5 lines Revert r61969 which added casts to Py_CHARMASK to avoid compiler warnings. Rather than sprinkle casts throughout the code, change Py_CHARMASK to always cast it's result to an unsigned char. This should ensure we do the right thing when accessing an array with the result. ........ r61992 | neal.norwitz | 2008-03-28 06:34:59 +0100 (Fri, 28 Mar 2008) | 2 lines Fix compiler warning about finite() missing on Solaris. ........ r61993 | neal.norwitz | 2008-03-28 07:34:03 +0100 (Fri, 28 Mar 2008) | 11 lines Bug 1503: Get the test to pass on OSX. This should make the test more reliable, but I'm not convinced it is the right solution. We need to determine if this causes the test to hang on any platforms or do other bad things. Even if it gets the test to pass reliably, it might be that we want to fix this in socket. The socket returned from accept() is different on different platforms (inheriting attributes or not) and we might want to ensure that the attributes (at least blocking) is the same across all platforms. ........ r61997 | neal.norwitz | 2008-03-28 08:36:31 +0100 (Fri, 28 Mar 2008) | 1 line Name the main method correctly so the test is run ........ r61998 | gregory.p.smith | 2008-03-28 09:00:44 +0100 (Fri, 28 Mar 2008) | 7 lines This patch moves some tests from test_urllib2_net to test_urllib2_localnet. The moved tests use a local server rather than going out to external servers. Accepts patch from issue2429. Contributed by Jerry Seutter & Michael Foord (fuzzyman) at PyCon 2008. ........ r61999 | georg.brandl | 2008-03-28 09:06:56 +0100 (Fri, 28 Mar 2008) | 2 lines #2406: add examples to gzip docs. ........ r62000 | gregory.p.smith | 2008-03-28 09:32:09 +0100 (Fri, 28 Mar 2008) | 4 lines Accept patch issue2426 by Paul Kippes (kippesp). Adds sqlite3.Connection.iterdump to allow dumping of databases. ........
2008-03-28 07:53:29 -03:00
Example of how to create a compressed GZIP file::
import gzip
2010-08-17 18:11:49 -03:00
content = b"Lots of content here"
with gzip.open('/home/joe/file.txt.gz', 'wb') as f:
f.write(content)
Merged revisions 61981,61984-61987,61992-61993,61997-62000 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r61981 | amaury.forgeotdarc | 2008-03-28 01:21:34 +0100 (Fri, 28 Mar 2008) | 2 lines test_future3.py is a regular test file, and should be part of the test suite ........ r61984 | jeffrey.yasskin | 2008-03-28 05:11:18 +0100 (Fri, 28 Mar 2008) | 6 lines Kill a race in test_threading in which the exception info in a thread finishing up after it was joined had a traceback pointing to that thread's (deleted) target attribute, while the test was trying to check that the target was destroyed. Big thanks to Antoine Pitrou for diagnosing the race and pointing out sys.exc_clear() to kill the exception early. This fixes issue 2496. ........ r61985 | neal.norwitz | 2008-03-28 05:41:34 +0100 (Fri, 28 Mar 2008) | 1 line Allow use of other ports so the test can pass if 9091 is in use ........ r61986 | jeffrey.yasskin | 2008-03-28 05:53:10 +0100 (Fri, 28 Mar 2008) | 2 lines Print more information the next time test_socket throws the wrong exception. ........ r61987 | neal.norwitz | 2008-03-28 05:58:51 +0100 (Fri, 28 Mar 2008) | 5 lines Revert r61969 which added casts to Py_CHARMASK to avoid compiler warnings. Rather than sprinkle casts throughout the code, change Py_CHARMASK to always cast it's result to an unsigned char. This should ensure we do the right thing when accessing an array with the result. ........ r61992 | neal.norwitz | 2008-03-28 06:34:59 +0100 (Fri, 28 Mar 2008) | 2 lines Fix compiler warning about finite() missing on Solaris. ........ r61993 | neal.norwitz | 2008-03-28 07:34:03 +0100 (Fri, 28 Mar 2008) | 11 lines Bug 1503: Get the test to pass on OSX. This should make the test more reliable, but I'm not convinced it is the right solution. We need to determine if this causes the test to hang on any platforms or do other bad things. Even if it gets the test to pass reliably, it might be that we want to fix this in socket. The socket returned from accept() is different on different platforms (inheriting attributes or not) and we might want to ensure that the attributes (at least blocking) is the same across all platforms. ........ r61997 | neal.norwitz | 2008-03-28 08:36:31 +0100 (Fri, 28 Mar 2008) | 1 line Name the main method correctly so the test is run ........ r61998 | gregory.p.smith | 2008-03-28 09:00:44 +0100 (Fri, 28 Mar 2008) | 7 lines This patch moves some tests from test_urllib2_net to test_urllib2_localnet. The moved tests use a local server rather than going out to external servers. Accepts patch from issue2429. Contributed by Jerry Seutter & Michael Foord (fuzzyman) at PyCon 2008. ........ r61999 | georg.brandl | 2008-03-28 09:06:56 +0100 (Fri, 28 Mar 2008) | 2 lines #2406: add examples to gzip docs. ........ r62000 | gregory.p.smith | 2008-03-28 09:32:09 +0100 (Fri, 28 Mar 2008) | 4 lines Accept patch issue2426 by Paul Kippes (kippesp). Adds sqlite3.Connection.iterdump to allow dumping of databases. ........
2008-03-28 07:53:29 -03:00
Example of how to GZIP compress an existing file::
import gzip
import shutil
2010-08-17 18:11:49 -03:00
with open('/home/joe/file.txt', 'rb') as f_in:
2010-08-17 18:24:05 -03:00
with gzip.open('/home/joe/file.txt.gz', 'wb') as f_out:
shutil.copyfileobj(f_in, f_out)
Merged revisions 61981,61984-61987,61992-61993,61997-62000 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r61981 | amaury.forgeotdarc | 2008-03-28 01:21:34 +0100 (Fri, 28 Mar 2008) | 2 lines test_future3.py is a regular test file, and should be part of the test suite ........ r61984 | jeffrey.yasskin | 2008-03-28 05:11:18 +0100 (Fri, 28 Mar 2008) | 6 lines Kill a race in test_threading in which the exception info in a thread finishing up after it was joined had a traceback pointing to that thread's (deleted) target attribute, while the test was trying to check that the target was destroyed. Big thanks to Antoine Pitrou for diagnosing the race and pointing out sys.exc_clear() to kill the exception early. This fixes issue 2496. ........ r61985 | neal.norwitz | 2008-03-28 05:41:34 +0100 (Fri, 28 Mar 2008) | 1 line Allow use of other ports so the test can pass if 9091 is in use ........ r61986 | jeffrey.yasskin | 2008-03-28 05:53:10 +0100 (Fri, 28 Mar 2008) | 2 lines Print more information the next time test_socket throws the wrong exception. ........ r61987 | neal.norwitz | 2008-03-28 05:58:51 +0100 (Fri, 28 Mar 2008) | 5 lines Revert r61969 which added casts to Py_CHARMASK to avoid compiler warnings. Rather than sprinkle casts throughout the code, change Py_CHARMASK to always cast it's result to an unsigned char. This should ensure we do the right thing when accessing an array with the result. ........ r61992 | neal.norwitz | 2008-03-28 06:34:59 +0100 (Fri, 28 Mar 2008) | 2 lines Fix compiler warning about finite() missing on Solaris. ........ r61993 | neal.norwitz | 2008-03-28 07:34:03 +0100 (Fri, 28 Mar 2008) | 11 lines Bug 1503: Get the test to pass on OSX. This should make the test more reliable, but I'm not convinced it is the right solution. We need to determine if this causes the test to hang on any platforms or do other bad things. Even if it gets the test to pass reliably, it might be that we want to fix this in socket. The socket returned from accept() is different on different platforms (inheriting attributes or not) and we might want to ensure that the attributes (at least blocking) is the same across all platforms. ........ r61997 | neal.norwitz | 2008-03-28 08:36:31 +0100 (Fri, 28 Mar 2008) | 1 line Name the main method correctly so the test is run ........ r61998 | gregory.p.smith | 2008-03-28 09:00:44 +0100 (Fri, 28 Mar 2008) | 7 lines This patch moves some tests from test_urllib2_net to test_urllib2_localnet. The moved tests use a local server rather than going out to external servers. Accepts patch from issue2429. Contributed by Jerry Seutter & Michael Foord (fuzzyman) at PyCon 2008. ........ r61999 | georg.brandl | 2008-03-28 09:06:56 +0100 (Fri, 28 Mar 2008) | 2 lines #2406: add examples to gzip docs. ........ r62000 | gregory.p.smith | 2008-03-28 09:32:09 +0100 (Fri, 28 Mar 2008) | 4 lines Accept patch issue2426 by Paul Kippes (kippesp). Adds sqlite3.Connection.iterdump to allow dumping of databases. ........
2008-03-28 07:53:29 -03:00
Example of how to GZIP compress a binary string::
import gzip
s_in = b"Lots of content here"
s_out = gzip.compress(s_in)
Merged revisions 61981,61984-61987,61992-61993,61997-62000 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r61981 | amaury.forgeotdarc | 2008-03-28 01:21:34 +0100 (Fri, 28 Mar 2008) | 2 lines test_future3.py is a regular test file, and should be part of the test suite ........ r61984 | jeffrey.yasskin | 2008-03-28 05:11:18 +0100 (Fri, 28 Mar 2008) | 6 lines Kill a race in test_threading in which the exception info in a thread finishing up after it was joined had a traceback pointing to that thread's (deleted) target attribute, while the test was trying to check that the target was destroyed. Big thanks to Antoine Pitrou for diagnosing the race and pointing out sys.exc_clear() to kill the exception early. This fixes issue 2496. ........ r61985 | neal.norwitz | 2008-03-28 05:41:34 +0100 (Fri, 28 Mar 2008) | 1 line Allow use of other ports so the test can pass if 9091 is in use ........ r61986 | jeffrey.yasskin | 2008-03-28 05:53:10 +0100 (Fri, 28 Mar 2008) | 2 lines Print more information the next time test_socket throws the wrong exception. ........ r61987 | neal.norwitz | 2008-03-28 05:58:51 +0100 (Fri, 28 Mar 2008) | 5 lines Revert r61969 which added casts to Py_CHARMASK to avoid compiler warnings. Rather than sprinkle casts throughout the code, change Py_CHARMASK to always cast it's result to an unsigned char. This should ensure we do the right thing when accessing an array with the result. ........ r61992 | neal.norwitz | 2008-03-28 06:34:59 +0100 (Fri, 28 Mar 2008) | 2 lines Fix compiler warning about finite() missing on Solaris. ........ r61993 | neal.norwitz | 2008-03-28 07:34:03 +0100 (Fri, 28 Mar 2008) | 11 lines Bug 1503: Get the test to pass on OSX. This should make the test more reliable, but I'm not convinced it is the right solution. We need to determine if this causes the test to hang on any platforms or do other bad things. Even if it gets the test to pass reliably, it might be that we want to fix this in socket. The socket returned from accept() is different on different platforms (inheriting attributes or not) and we might want to ensure that the attributes (at least blocking) is the same across all platforms. ........ r61997 | neal.norwitz | 2008-03-28 08:36:31 +0100 (Fri, 28 Mar 2008) | 1 line Name the main method correctly so the test is run ........ r61998 | gregory.p.smith | 2008-03-28 09:00:44 +0100 (Fri, 28 Mar 2008) | 7 lines This patch moves some tests from test_urllib2_net to test_urllib2_localnet. The moved tests use a local server rather than going out to external servers. Accepts patch from issue2429. Contributed by Jerry Seutter & Michael Foord (fuzzyman) at PyCon 2008. ........ r61999 | georg.brandl | 2008-03-28 09:06:56 +0100 (Fri, 28 Mar 2008) | 2 lines #2406: add examples to gzip docs. ........ r62000 | gregory.p.smith | 2008-03-28 09:32:09 +0100 (Fri, 28 Mar 2008) | 4 lines Accept patch issue2426 by Paul Kippes (kippesp). Adds sqlite3.Connection.iterdump to allow dumping of databases. ........
2008-03-28 07:53:29 -03:00
2007-08-15 11:28:22 -03:00
.. seealso::
Module :mod:`zlib`
The basic data compression module needed to support the :program:`gzip` file
format.
.. program:: gzip
Command Line Interface
----------------------
The :mod:`gzip` module provides a simple command line interface to compress or
decompress files.
Once executed the :mod:`gzip` module keeps the input file(s).
.. versionchanged:: 3.8
Add a new command line interface with a usage.
By default, when you will execute the CLI, the default compression level is 6.
Command line options
^^^^^^^^^^^^^^^^^^^^
.. cmdoption:: file
If *file* is not specified, read from :attr:`sys.stdin`.
.. cmdoption:: --fast
Indicates the fastest compression method (less compression).
.. cmdoption:: --best
Indicates the slowest compression method (best compression).
.. cmdoption:: -d, --decompress
Decompress the given file.
.. cmdoption:: -h, --help
Show the help message.