cpython/Doc/library/configparser.rst

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:mod:`ConfigParser` --- Configuration file parser
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=================================================
.. module:: ConfigParser
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:synopsis: Configuration file parser.
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.. moduleauthor:: Ken Manheimer <klm@zope.com>
.. moduleauthor:: Barry Warsaw <bwarsaw@python.org>
.. moduleauthor:: Eric S. Raymond <esr@thyrsus.com>
.. sectionauthor:: Christopher G. Petrilli <petrilli@amber.org>
.. note::
Merged revisions 68133-68134,68141-68142,68145-68146,68148-68149,68159-68162,68166,68171-68174,68179,68195-68196,68210,68214-68215,68217-68222 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r68133 | antoine.pitrou | 2009-01-01 16:38:03 +0100 (Thu, 01 Jan 2009) | 1 line fill in actual issue number in tests ........ r68134 | hirokazu.yamamoto | 2009-01-01 16:45:39 +0100 (Thu, 01 Jan 2009) | 2 lines Issue #4797: IOError.filename was not set when _fileio.FileIO failed to open file with `str' filename on Windows. ........ r68141 | benjamin.peterson | 2009-01-01 17:43:12 +0100 (Thu, 01 Jan 2009) | 1 line fix highlighting ........ r68142 | benjamin.peterson | 2009-01-01 18:29:49 +0100 (Thu, 01 Jan 2009) | 2 lines welcome to 2009, Python! ........ r68145 | amaury.forgeotdarc | 2009-01-02 01:03:54 +0100 (Fri, 02 Jan 2009) | 5 lines #4801 _collections module fails to build on cygwin. _PyObject_GC_TRACK is the macro version of PyObject_GC_Track, and according to documentation it should not be used for extension modules. ........ r68146 | ronald.oussoren | 2009-01-02 11:44:46 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4472: "configure --enable-shared doesn't work on OSX" ........ r68148 | ronald.oussoren | 2009-01-02 11:48:31 +0100 (Fri, 02 Jan 2009) | 2 lines Forgot to add a NEWS item in my previous checkin ........ r68149 | ronald.oussoren | 2009-01-02 11:50:48 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue4780 ........ r68159 | ronald.oussoren | 2009-01-02 15:48:17 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue 1627952 ........ r68160 | ronald.oussoren | 2009-01-02 15:52:09 +0100 (Fri, 02 Jan 2009) | 2 lines Fix for issue r1737832 ........ r68161 | ronald.oussoren | 2009-01-02 16:00:05 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 1149804 ........ r68162 | ronald.oussoren | 2009-01-02 16:06:00 +0100 (Fri, 02 Jan 2009) | 3 lines Fix for issue 4472 is incompatible with Cygwin, this patch should fix that. ........ r68166 | benjamin.peterson | 2009-01-02 19:26:23 +0100 (Fri, 02 Jan 2009) | 1 line document PyMemberDef ........ r68171 | georg.brandl | 2009-01-02 21:25:14 +0100 (Fri, 02 Jan 2009) | 3 lines #4811: fix markup glitches (mostly remains of the conversion), found by Gabriel Genellina. ........ r68172 | martin.v.loewis | 2009-01-02 21:32:55 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4075: Use OutputDebugStringW in Py_FatalError. ........ r68173 | martin.v.loewis | 2009-01-02 21:40:14 +0100 (Fri, 02 Jan 2009) | 2 lines Issue #4051: Prevent conflict of UNICODE macros in cPickle. ........ r68174 | benjamin.peterson | 2009-01-02 21:47:27 +0100 (Fri, 02 Jan 2009) | 1 line fix compilation on non-Windows platforms ........ r68179 | raymond.hettinger | 2009-01-02 22:26:45 +0100 (Fri, 02 Jan 2009) | 1 line Issue #4615. Document how to use itertools for de-duping. ........ r68195 | georg.brandl | 2009-01-03 14:45:15 +0100 (Sat, 03 Jan 2009) | 2 lines Remove useless string literal. ........ r68196 | georg.brandl | 2009-01-03 15:29:53 +0100 (Sat, 03 Jan 2009) | 2 lines Fix indentation. ........ r68210 | georg.brandl | 2009-01-03 20:10:12 +0100 (Sat, 03 Jan 2009) | 2 lines Set eol-style correctly for mp_distributing.py. ........ r68214 | georg.brandl | 2009-01-03 20:44:48 +0100 (Sat, 03 Jan 2009) | 2 lines Make indentation consistent. ........ r68215 | georg.brandl | 2009-01-03 21:15:14 +0100 (Sat, 03 Jan 2009) | 2 lines Fix role name. ........ r68217 | georg.brandl | 2009-01-03 21:30:15 +0100 (Sat, 03 Jan 2009) | 2 lines Add rstlint, a little tool to find subtle markup problems and inconsistencies in the Doc sources. ........ r68218 | georg.brandl | 2009-01-03 21:38:59 +0100 (Sat, 03 Jan 2009) | 2 lines Recognize usage of the default role. ........ r68219 | georg.brandl | 2009-01-03 21:47:01 +0100 (Sat, 03 Jan 2009) | 2 lines Fix uses of the default role. ........ r68220 | georg.brandl | 2009-01-03 21:55:06 +0100 (Sat, 03 Jan 2009) | 2 lines Remove trailing whitespace. ........ r68221 | georg.brandl | 2009-01-03 22:04:55 +0100 (Sat, 03 Jan 2009) | 2 lines Remove tabs from the documentation. ........ r68222 | georg.brandl | 2009-01-03 22:11:58 +0100 (Sat, 03 Jan 2009) | 2 lines Disable the line length checker by default. ........
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The :mod:`ConfigParser` module has been renamed to :mod:`configparser` in
Python 3.0. The :term:`2to3` tool will automatically adapt imports when
converting your sources to 3.0.
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.. index::
pair: .ini; file
pair: configuration; file
single: ini file
single: Windows ini file
This module defines the class :class:`ConfigParser`. The :class:`ConfigParser`
class implements a basic configuration file parser language which provides a
structure similar to what you would find on Microsoft Windows INI files. You
can use this to write Python programs which can be customized by end users
easily.
.. warning::
This library does *not* interpret or write the value-type prefixes used in the
Windows Registry extended version of INI syntax.
The configuration file consists of sections, led by a ``[section]`` header and
followed by ``name: value`` entries, with continuations in the style of
:rfc:`822` (see section 3.1.1, "LONG HEADER FIELDS"); ``name=value`` is also
accepted. Note that leading whitespace is removed from values. The optional
values can contain format strings which refer to other values in the same
section, or values in a special ``DEFAULT`` section. Additional defaults can be
provided on initialization and retrieval. Lines beginning with ``'#'`` or
``';'`` are ignored and may be used to provide comments.
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For example::
[My Section]
foodir: %(dir)s/whatever
dir=frob
long: this value continues
in the next line
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would resolve the ``%(dir)s`` to the value of ``dir`` (``frob`` in this case).
All reference expansions are done on demand.
Default values can be specified by passing them into the :class:`ConfigParser`
constructor as a dictionary. Additional defaults may be passed into the
:meth:`get` method which will override all others.
Sections are normally stored in a builtin dictionary. An alternative dictionary
type can be passed to the :class:`ConfigParser` constructor. For example, if a
dictionary type is passed that sorts its keys, the sections will be sorted on
write-back, as will be the keys within each section.
.. class:: RawConfigParser([defaults[, dict_type]])
The basic configuration object. When *defaults* is given, it is initialized
into the dictionary of intrinsic defaults. When *dict_type* is given, it will
be used to create the dictionary objects for the list of sections, for the
options within a section, and for the default values. This class does not
support the magical interpolation behavior.
.. versionadded:: 2.3
.. versionchanged:: 2.6
*dict_type* was added.
.. class:: ConfigParser([defaults])
Derived class of :class:`RawConfigParser` that implements the magical
interpolation feature and adds optional arguments to the :meth:`get` and
:meth:`items` methods. The values in *defaults* must be appropriate for the
``%()s`` string interpolation. Note that *__name__* is an intrinsic default;
its value is the section name, and will override any value provided in
*defaults*.
All option names used in interpolation will be passed through the
:meth:`optionxform` method just like any other option name reference. For
example, using the default implementation of :meth:`optionxform` (which converts
option names to lower case), the values ``foo %(bar)s`` and ``foo %(BAR)s`` are
equivalent.
.. class:: SafeConfigParser([defaults])
Derived class of :class:`ConfigParser` that implements a more-sane variant of
the magical interpolation feature. This implementation is more predictable as
well. New applications should prefer this version if they don't need to be
compatible with older versions of Python.
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.. XXX Need to explain what's safer/more predictable about it.
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.. versionadded:: 2.3
.. exception:: NoSectionError
Exception raised when a specified section is not found.
.. exception:: DuplicateSectionError
Exception raised if :meth:`add_section` is called with the name of a section
that is already present.
.. exception:: NoOptionError
Exception raised when a specified option is not found in the specified section.
.. exception:: InterpolationError
Base class for exceptions raised when problems occur performing string
interpolation.
.. exception:: InterpolationDepthError
Exception raised when string interpolation cannot be completed because the
number of iterations exceeds :const:`MAX_INTERPOLATION_DEPTH`. Subclass of
:exc:`InterpolationError`.
.. exception:: InterpolationMissingOptionError
Exception raised when an option referenced from a value does not exist. Subclass
of :exc:`InterpolationError`.
.. versionadded:: 2.3
.. exception:: InterpolationSyntaxError
Exception raised when the source text into which substitutions are made does not
conform to the required syntax. Subclass of :exc:`InterpolationError`.
.. versionadded:: 2.3
.. exception:: MissingSectionHeaderError
Exception raised when attempting to parse a file which has no section headers.
.. exception:: ParsingError
Exception raised when errors occur attempting to parse a file.
.. data:: MAX_INTERPOLATION_DEPTH
The maximum depth for recursive interpolation for :meth:`get` when the *raw*
parameter is false. This is relevant only for the :class:`ConfigParser` class.
.. seealso::
Module :mod:`shlex`
Support for a creating Unix shell-like mini-languages which can be used as an
alternate format for application configuration files.
.. _rawconfigparser-objects:
RawConfigParser Objects
-----------------------
:class:`RawConfigParser` instances have the following methods:
.. method:: RawConfigParser.defaults()
Return a dictionary containing the instance-wide defaults.
.. method:: RawConfigParser.sections()
Return a list of the sections available; ``DEFAULT`` is not included in the
list.
.. method:: RawConfigParser.add_section(section)
Add a section named *section* to the instance. If a section by the given name
already exists, :exc:`DuplicateSectionError` is raised. If the name
``DEFAULT`` (or any of it's case-insensitive variants) is passed,
:exc:`ValueError` is raised.
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.. method:: RawConfigParser.has_section(section)
Indicates whether the named section is present in the configuration. The
``DEFAULT`` section is not acknowledged.
.. method:: RawConfigParser.options(section)
Returns a list of options available in the specified *section*.
.. method:: RawConfigParser.has_option(section, option)
If the given section exists, and contains the given option, return
:const:`True`; otherwise return :const:`False`.
.. versionadded:: 1.6
.. method:: RawConfigParser.read(filenames)
Attempt to read and parse a list of filenames, returning a list of filenames
which were successfully parsed. If *filenames* is a string or Unicode string,
it is treated as a single filename. If a file named in *filenames* cannot be
opened, that file will be ignored. This is designed so that you can specify a
list of potential configuration file locations (for example, the current
directory, the user's home directory, and some system-wide directory), and all
existing configuration files in the list will be read. If none of the named
files exist, the :class:`ConfigParser` instance will contain an empty dataset.
An application which requires initial values to be loaded from a file should
load the required file or files using :meth:`readfp` before calling :meth:`read`
for any optional files::
import ConfigParser, os
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config = ConfigParser.ConfigParser()
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config.readfp(open('defaults.cfg'))
config.read(['site.cfg', os.path.expanduser('~/.myapp.cfg')])
.. versionchanged:: 2.4
Returns list of successfully parsed filenames.
.. method:: RawConfigParser.readfp(fp[, filename])
Read and parse configuration data from the file or file-like object in *fp*
(only the :meth:`readline` method is used). If *filename* is omitted and *fp*
has a :attr:`name` attribute, that is used for *filename*; the default is
``<???>``.
.. method:: RawConfigParser.get(section, option)
Get an *option* value for the named *section*.
.. method:: RawConfigParser.getint(section, option)
A convenience method which coerces the *option* in the specified *section* to an
integer.
.. method:: RawConfigParser.getfloat(section, option)
A convenience method which coerces the *option* in the specified *section* to a
floating point number.
.. method:: RawConfigParser.getboolean(section, option)
A convenience method which coerces the *option* in the specified *section* to a
Boolean value. Note that the accepted values for the option are ``"1"``,
``"yes"``, ``"true"``, and ``"on"``, which cause this method to return ``True``,
and ``"0"``, ``"no"``, ``"false"``, and ``"off"``, which cause it to return
``False``. These string values are checked in a case-insensitive manner. Any
other value will cause it to raise :exc:`ValueError`.
.. method:: RawConfigParser.items(section)
Return a list of ``(name, value)`` pairs for each option in the given *section*.
.. method:: RawConfigParser.set(section, option, value)
If the given section exists, set the given option to the specified value;
otherwise raise :exc:`NoSectionError`. While it is possible to use
:class:`RawConfigParser` (or :class:`ConfigParser` with *raw* parameters set to
true) for *internal* storage of non-string values, full functionality (including
interpolation and output to files) can only be achieved using string values.
.. versionadded:: 1.6
.. method:: RawConfigParser.write(fileobject)
Write a representation of the configuration to the specified file object. This
representation can be parsed by a future :meth:`read` call.
.. versionadded:: 1.6
.. method:: RawConfigParser.remove_option(section, option)
Remove the specified *option* from the specified *section*. If the section does
not exist, raise :exc:`NoSectionError`. If the option existed to be removed,
return :const:`True`; otherwise return :const:`False`.
.. versionadded:: 1.6
.. method:: RawConfigParser.remove_section(section)
Remove the specified *section* from the configuration. If the section in fact
existed, return ``True``. Otherwise return ``False``.
.. method:: RawConfigParser.optionxform(option)
Transforms the option name *option* as found in an input file or as passed in by
client code to the form that should be used in the internal structures. The
default implementation returns a lower-case version of *option*; subclasses may
override this or client code can set an attribute of this name on instances to
affect this behavior. Setting this to :func:`str`, for example, would make
option names case sensitive.
.. _configparser-objects:
ConfigParser Objects
--------------------
The :class:`ConfigParser` class extends some methods of the
:class:`RawConfigParser` interface, adding some optional arguments.
.. method:: ConfigParser.get(section, option[, raw[, vars]])
Get an *option* value for the named *section*. All the ``'%'`` interpolations
are expanded in the return values, based on the defaults passed into the
constructor, as well as the options *vars* provided, unless the *raw* argument
is true.
.. method:: ConfigParser.items(section[, raw[, vars]])
Return a list of ``(name, value)`` pairs for each option in the given *section*.
Optional arguments have the same meaning as for the :meth:`get` method.
.. versionadded:: 2.3
.. _safeconfigparser-objects:
SafeConfigParser Objects
------------------------
The :class:`SafeConfigParser` class implements the same extended interface as
:class:`ConfigParser`, with the following addition:
.. method:: SafeConfigParser.set(section, option, value)
If the given section exists, set the given option to the specified value;
otherwise raise :exc:`NoSectionError`. *value* must be a string (:class:`str`
or :class:`unicode`); if not, :exc:`TypeError` is raised.
.. versionadded:: 2.4
Examples
--------
An example of writing to a configuration file::
import ConfigParser
config = ConfigParser.RawConfigParser()
# When adding sections or items, add them in the reverse order of
# how you want them to be displayed in the actual file.
# In addition, please note that using RawConfigParser's and the raw
# mode of ConfigParser's respective set functions, you can assign
# non-string values to keys internally, but will receive an error
# when attempting to write to a file or when you get it in non-raw
# mode. SafeConfigParser does not allow such assignments to take place.
config.add_section('Section1')
config.set('Section1', 'int', '15')
config.set('Section1', 'bool', 'true')
config.set('Section1', 'float', '3.1415')
config.set('Section1', 'baz', 'fun')
config.set('Section1', 'bar', 'Python')
config.set('Section1', 'foo', '%(bar)s is %(baz)s!')
# Writing our configuration file to 'example.cfg'
with open('example.cfg', 'wb') as configfile:
config.write(configfile)
An example of reading the configuration file again::
import ConfigParser
config = ConfigParser.RawConfigParser()
config.read('example.cfg')
# getfloat() raises an exception if the value is not a float
# getint() and getboolean() also do this for their respective types
float = config.getfloat('Section1', 'float')
int = config.getint('Section1', 'int')
print float + int
# Notice that the next output does not interpolate '%(bar)s' or '%(baz)s'.
# This is because we are using a RawConfigParser().
if config.getboolean('Section1', 'bool'):
print config.get('Section1', 'foo')
To get interpolation, you will need to use a :class:`ConfigParser` or
:class:`SafeConfigParser`::
import ConfigParser
config = ConfigParser.ConfigParser()
config.read('example.cfg')
# Set the third, optional argument of get to 1 if you wish to use raw mode.
print config.get('Section1', 'foo', 0) # -> "Python is fun!"
print config.get('Section1', 'foo', 1) # -> "%(bar)s is %(baz)s!"
# The optional fourth argument is a dict with members that will take
# precedence in interpolation.
print config.get('Section1', 'foo', 0, {'bar': 'Documentation',
'baz': 'evil'})
Defaults are available in all three types of ConfigParsers. They are used in
interpolation if an option used is not defined elsewhere. ::
import ConfigParser
# New instance with 'bar' and 'baz' defaulting to 'Life' and 'hard' each
config = ConfigParser.SafeConfigParser({'bar': 'Life', 'baz': 'hard'})
config.read('example.cfg')
print config.get('Section1', 'foo') # -> "Python is fun!"
config.remove_option('Section1', 'bar')
config.remove_option('Section1', 'baz')
print config.get('Section1', 'foo') # -> "Life is hard!"
The function ``opt_move`` below can be used to move options between sections::
def opt_move(config, section1, section2, option):
try:
config.set(section2, option, config.get(section1, option, 1))
except ConfigParser.NoSectionError:
# Create non-existent section
config.add_section(section2)
opt_move(config, section1, section2, option)
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else:
config.remove_option(section1, option)