1 :mod:`ConfigParser` --- Configuration file parser
2 =================================================
4 .. module:: ConfigParser
5 :synopsis: Configuration file parser.
7 .. moduleauthor:: Ken Manheimer <klm@zope.com>
8 .. moduleauthor:: Barry Warsaw <bwarsaw@python.org>
9 .. moduleauthor:: Eric S. Raymond <esr@thyrsus.com>
10 .. sectionauthor:: Christopher G. Petrilli <petrilli@amber.org>
14 The :mod:`ConfigParser` module has been renamed to :mod:`configparser` in
15 Python 3.0. The :term:`2to3` tool will automatically adapt imports when
16 converting your sources to 3.0.
20 pair: configuration; file
22 single: Windows ini file
24 This module defines the class :class:`ConfigParser`. The :class:`ConfigParser`
25 class implements a basic configuration file parser language which provides a
26 structure similar to what you would find on Microsoft Windows INI files. You
27 can use this to write Python programs which can be customized by end users
32 This library does *not* interpret or write the value-type prefixes used in
33 the Windows Registry extended version of INI syntax.
35 The configuration file consists of sections, led by a ``[section]`` header and
36 followed by ``name: value`` entries, with continuations in the style of
37 :rfc:`822` (see section 3.1.1, "LONG HEADER FIELDS"); ``name=value`` is also
38 accepted. Note that leading whitespace is removed from values. The optional
39 values can contain format strings which refer to other values in the same
40 section, or values in a special ``DEFAULT`` section. Additional defaults can be
41 provided on initialization and retrieval. Lines beginning with ``'#'`` or
42 ``';'`` are ignored and may be used to provide comments.
44 Configuration files may include comments, prefixed by specific characters (``#``
45 and ``;``). Comments may appear on their own in an otherwise empty line, or may
46 be entered in lines holding values or section names. In the latter case, they
47 need to be preceded by a whitespace character to be recognized as a comment.
48 (For backwards compatibility, only ``;`` starts an inline comment, while ``#``
51 On top of the core functionality, :class:`SafeConfigParser` supports
52 interpolation. This means values can contain format strings which refer to
53 other values in the same section, or values in a special ``DEFAULT`` section.
54 Additional defaults can be provided on initialization.
59 foodir: %(dir)s/whatever
61 long: this value continues
64 would resolve the ``%(dir)s`` to the value of ``dir`` (``frob`` in this case).
65 All reference expansions are done on demand.
67 Default values can be specified by passing them into the :class:`ConfigParser`
68 constructor as a dictionary. Additional defaults may be passed into the
69 :meth:`get` method which will override all others.
71 Sections are normally stored in a built-in dictionary. An alternative dictionary
72 type can be passed to the :class:`ConfigParser` constructor. For example, if a
73 dictionary type is passed that sorts its keys, the sections will be sorted on
74 write-back, as will be the keys within each section.
77 .. class:: RawConfigParser([defaults[, dict_type[, allow_no_value]]])
79 The basic configuration object. When *defaults* is given, it is initialized
80 into the dictionary of intrinsic defaults. When *dict_type* is given, it will
81 be used to create the dictionary objects for the list of sections, for the
82 options within a section, and for the default values. When *allow_no_value*
83 is true (default: ``False``), options without values are accepted; the value
84 presented for these is ``None``.
87 support the magical interpolation behavior.
91 .. versionchanged:: 2.6
92 *dict_type* was added.
94 .. versionchanged:: 2.7
95 The default *dict_type* is :class:`collections.OrderedDict`.
96 *allow_no_value* was added.
99 .. class:: ConfigParser([defaults[, dict_type[, allow_no_value]]])
101 Derived class of :class:`RawConfigParser` that implements the magical
102 interpolation feature and adds optional arguments to the :meth:`get` and
103 :meth:`items` methods. The values in *defaults* must be appropriate for the
104 ``%()s`` string interpolation. Note that *__name__* is an intrinsic default;
105 its value is the section name, and will override any value provided in
108 All option names used in interpolation will be passed through the
109 :meth:`optionxform` method just like any other option name reference. For
110 example, using the default implementation of :meth:`optionxform` (which converts
111 option names to lower case), the values ``foo %(bar)s`` and ``foo %(BAR)s`` are
114 .. versionadded:: 2.3
116 .. versionchanged:: 2.6
117 *dict_type* was added.
119 .. versionchanged:: 2.7
120 The default *dict_type* is :class:`collections.OrderedDict`.
121 *allow_no_value* was added.
124 .. class:: SafeConfigParser([defaults[, dict_type[, allow_no_value]]])
126 Derived class of :class:`ConfigParser` that implements a more-sane variant of
127 the magical interpolation feature. This implementation is more predictable as
128 well. New applications should prefer this version if they don't need to be
129 compatible with older versions of Python.
131 .. XXX Need to explain what's safer/more predictable about it.
133 .. versionadded:: 2.3
135 .. versionchanged:: 2.6
136 *dict_type* was added.
138 .. versionchanged:: 2.7
139 The default *dict_type* is :class:`collections.OrderedDict`.
140 *allow_no_value* was added.
145 Base class for all other configparser exceptions.
148 .. exception:: NoSectionError
150 Exception raised when a specified section is not found.
153 .. exception:: DuplicateSectionError
155 Exception raised if :meth:`add_section` is called with the name of a section
156 that is already present.
159 .. exception:: NoOptionError
161 Exception raised when a specified option is not found in the specified section.
164 .. exception:: InterpolationError
166 Base class for exceptions raised when problems occur performing string
170 .. exception:: InterpolationDepthError
172 Exception raised when string interpolation cannot be completed because the
173 number of iterations exceeds :const:`MAX_INTERPOLATION_DEPTH`. Subclass of
174 :exc:`InterpolationError`.
177 .. exception:: InterpolationMissingOptionError
179 Exception raised when an option referenced from a value does not exist. Subclass
180 of :exc:`InterpolationError`.
182 .. versionadded:: 2.3
185 .. exception:: InterpolationSyntaxError
187 Exception raised when the source text into which substitutions are made does not
188 conform to the required syntax. Subclass of :exc:`InterpolationError`.
190 .. versionadded:: 2.3
193 .. exception:: MissingSectionHeaderError
195 Exception raised when attempting to parse a file which has no section headers.
198 .. exception:: ParsingError
200 Exception raised when errors occur attempting to parse a file.
203 .. data:: MAX_INTERPOLATION_DEPTH
205 The maximum depth for recursive interpolation for :meth:`get` when the *raw*
206 parameter is false. This is relevant only for the :class:`ConfigParser` class.
212 Support for a creating Unix shell-like mini-languages which can be used as an
213 alternate format for application configuration files.
216 .. _rawconfigparser-objects:
218 RawConfigParser Objects
219 -----------------------
221 :class:`RawConfigParser` instances have the following methods:
224 .. method:: RawConfigParser.defaults()
226 Return a dictionary containing the instance-wide defaults.
229 .. method:: RawConfigParser.sections()
231 Return a list of the sections available; ``DEFAULT`` is not included in the
235 .. method:: RawConfigParser.add_section(section)
237 Add a section named *section* to the instance. If a section by the given name
238 already exists, :exc:`DuplicateSectionError` is raised. If the name
239 ``DEFAULT`` (or any of it's case-insensitive variants) is passed,
240 :exc:`ValueError` is raised.
242 .. method:: RawConfigParser.has_section(section)
244 Indicates whether the named section is present in the configuration. The
245 ``DEFAULT`` section is not acknowledged.
248 .. method:: RawConfigParser.options(section)
250 Returns a list of options available in the specified *section*.
253 .. method:: RawConfigParser.has_option(section, option)
255 If the given section exists, and contains the given option, return
256 :const:`True`; otherwise return :const:`False`.
258 .. versionadded:: 1.6
261 .. method:: RawConfigParser.read(filenames)
263 Attempt to read and parse a list of filenames, returning a list of filenames
264 which were successfully parsed. If *filenames* is a string or Unicode string,
265 it is treated as a single filename. If a file named in *filenames* cannot be
266 opened, that file will be ignored. This is designed so that you can specify a
267 list of potential configuration file locations (for example, the current
268 directory, the user's home directory, and some system-wide directory), and all
269 existing configuration files in the list will be read. If none of the named
270 files exist, the :class:`ConfigParser` instance will contain an empty dataset.
271 An application which requires initial values to be loaded from a file should
272 load the required file or files using :meth:`readfp` before calling :meth:`read`
273 for any optional files::
275 import ConfigParser, os
277 config = ConfigParser.ConfigParser()
278 config.readfp(open('defaults.cfg'))
279 config.read(['site.cfg', os.path.expanduser('~/.myapp.cfg')])
281 .. versionchanged:: 2.4
282 Returns list of successfully parsed filenames.
285 .. method:: RawConfigParser.readfp(fp[, filename])
287 Read and parse configuration data from the file or file-like object in *fp*
288 (only the :meth:`readline` method is used). If *filename* is omitted and *fp*
289 has a :attr:`name` attribute, that is used for *filename*; the default is
293 .. method:: RawConfigParser.get(section, option)
295 Get an *option* value for the named *section*.
298 .. method:: RawConfigParser.getint(section, option)
300 A convenience method which coerces the *option* in the specified *section* to an
304 .. method:: RawConfigParser.getfloat(section, option)
306 A convenience method which coerces the *option* in the specified *section* to a
307 floating point number.
310 .. method:: RawConfigParser.getboolean(section, option)
312 A convenience method which coerces the *option* in the specified *section* to a
313 Boolean value. Note that the accepted values for the option are ``"1"``,
314 ``"yes"``, ``"true"``, and ``"on"``, which cause this method to return ``True``,
315 and ``"0"``, ``"no"``, ``"false"``, and ``"off"``, which cause it to return
316 ``False``. These string values are checked in a case-insensitive manner. Any
317 other value will cause it to raise :exc:`ValueError`.
320 .. method:: RawConfigParser.items(section)
322 Return a list of ``(name, value)`` pairs for each option in the given *section*.
325 .. method:: RawConfigParser.set(section, option, value)
327 If the given section exists, set the given option to the specified value;
328 otherwise raise :exc:`NoSectionError`. While it is possible to use
329 :class:`RawConfigParser` (or :class:`ConfigParser` with *raw* parameters set to
330 true) for *internal* storage of non-string values, full functionality (including
331 interpolation and output to files) can only be achieved using string values.
333 .. versionadded:: 1.6
336 .. method:: RawConfigParser.write(fileobject)
338 Write a representation of the configuration to the specified file object. This
339 representation can be parsed by a future :meth:`read` call.
341 .. versionadded:: 1.6
344 .. method:: RawConfigParser.remove_option(section, option)
346 Remove the specified *option* from the specified *section*. If the section does
347 not exist, raise :exc:`NoSectionError`. If the option existed to be removed,
348 return :const:`True`; otherwise return :const:`False`.
350 .. versionadded:: 1.6
353 .. method:: RawConfigParser.remove_section(section)
355 Remove the specified *section* from the configuration. If the section in fact
356 existed, return ``True``. Otherwise return ``False``.
359 .. method:: RawConfigParser.optionxform(option)
361 Transforms the option name *option* as found in an input file or as passed in
362 by client code to the form that should be used in the internal structures.
363 The default implementation returns a lower-case version of *option*;
364 subclasses may override this or client code can set an attribute of this name
365 on instances to affect this behavior.
367 You don't necessarily need to subclass a ConfigParser to use this method, you
368 can also re-set it on an instance, to a function that takes a string
369 argument. Setting it to ``str``, for example, would make option names case
372 cfgparser = ConfigParser()
374 cfgparser.optionxform = str
376 Note that when reading configuration files, whitespace around the
377 option names are stripped before :meth:`optionxform` is called.
380 .. _configparser-objects:
385 The :class:`ConfigParser` class extends some methods of the
386 :class:`RawConfigParser` interface, adding some optional arguments.
389 .. method:: ConfigParser.get(section, option[, raw[, vars]])
391 Get an *option* value for the named *section*. If *vars* is provided, it
392 must be a dictionary. The *option* is looked up in *vars* (if provided),
393 *section*, and in *defaults* in that order.
395 All the ``'%'`` interpolations are expanded in the return values, unless the
396 *raw* argument is true. Values for interpolation keys are looked up in the
397 same manner as the option.
399 .. method:: ConfigParser.items(section[, raw[, vars]])
401 Return a list of ``(name, value)`` pairs for each option in the given *section*.
402 Optional arguments have the same meaning as for the :meth:`get` method.
404 .. versionadded:: 2.3
407 .. _safeconfigparser-objects:
409 SafeConfigParser Objects
410 ------------------------
412 The :class:`SafeConfigParser` class implements the same extended interface as
413 :class:`ConfigParser`, with the following addition:
416 .. method:: SafeConfigParser.set(section, option, value)
418 If the given section exists, set the given option to the specified value;
419 otherwise raise :exc:`NoSectionError`. *value* must be a string (:class:`str`
420 or :class:`unicode`); if not, :exc:`TypeError` is raised.
422 .. versionadded:: 2.4
428 An example of writing to a configuration file::
432 config = ConfigParser.RawConfigParser()
434 # When adding sections or items, add them in the reverse order of
435 # how you want them to be displayed in the actual file.
436 # In addition, please note that using RawConfigParser's and the raw
437 # mode of ConfigParser's respective set functions, you can assign
438 # non-string values to keys internally, but will receive an error
439 # when attempting to write to a file or when you get it in non-raw
440 # mode. SafeConfigParser does not allow such assignments to take place.
441 config.add_section('Section1')
442 config.set('Section1', 'int', '15')
443 config.set('Section1', 'bool', 'true')
444 config.set('Section1', 'float', '3.1415')
445 config.set('Section1', 'baz', 'fun')
446 config.set('Section1', 'bar', 'Python')
447 config.set('Section1', 'foo', '%(bar)s is %(baz)s!')
449 # Writing our configuration file to 'example.cfg'
450 with open('example.cfg', 'wb') as configfile:
451 config.write(configfile)
453 An example of reading the configuration file again::
457 config = ConfigParser.RawConfigParser()
458 config.read('example.cfg')
460 # getfloat() raises an exception if the value is not a float
461 # getint() and getboolean() also do this for their respective types
462 float = config.getfloat('Section1', 'float')
463 int = config.getint('Section1', 'int')
466 # Notice that the next output does not interpolate '%(bar)s' or '%(baz)s'.
467 # This is because we are using a RawConfigParser().
468 if config.getboolean('Section1', 'bool'):
469 print config.get('Section1', 'foo')
471 To get interpolation, you will need to use a :class:`ConfigParser` or
472 :class:`SafeConfigParser`::
476 config = ConfigParser.ConfigParser()
477 config.read('example.cfg')
479 # Set the third, optional argument of get to 1 if you wish to use raw mode.
480 print config.get('Section1', 'foo', 0) # -> "Python is fun!"
481 print config.get('Section1', 'foo', 1) # -> "%(bar)s is %(baz)s!"
483 # The optional fourth argument is a dict with members that will take
484 # precedence in interpolation.
485 print config.get('Section1', 'foo', 0, {'bar': 'Documentation',
488 Defaults are available in all three types of ConfigParsers. They are used in
489 interpolation if an option used is not defined elsewhere. ::
493 # New instance with 'bar' and 'baz' defaulting to 'Life' and 'hard' each
494 config = ConfigParser.SafeConfigParser({'bar': 'Life', 'baz': 'hard'})
495 config.read('example.cfg')
497 print config.get('Section1', 'foo') # -> "Python is fun!"
498 config.remove_option('Section1', 'bar')
499 config.remove_option('Section1', 'baz')
500 print config.get('Section1', 'foo') # -> "Life is hard!"
502 The function ``opt_move`` below can be used to move options between sections::
504 def opt_move(config, section1, section2, option):
506 config.set(section2, option, config.get(section1, option, 1))
507 except ConfigParser.NoSectionError:
508 # Create non-existent section
509 config.add_section(section2)
510 opt_move(config, section1, section2, option)
512 config.remove_option(section1, option)
514 Some configuration files are known to include settings without values, but which
515 otherwise conform to the syntax supported by :mod:`ConfigParser`. The
516 *allow_no_value* parameter to the constructor can be used to indicate that such
517 values should be accepted:
521 >>> import ConfigParser
524 >>> sample_config = """
527 ... pid-file = /var/run/mysqld/mysqld.pid
528 ... skip-external-locking
529 ... old_passwords = 1
533 >>> config = ConfigParser.RawConfigParser(allow_no_value=True)
534 >>> config.readfp(io.BytesIO(sample_config))
536 >>> # Settings with values are treated as before:
537 >>> config.get("mysqld", "user")
540 >>> # Settings without values provide None:
541 >>> config.get("mysqld", "skip-bdb")
543 >>> # Settings which aren't specified still raise an error:
544 >>> config.get("mysqld", "does-not-exist")
545 Traceback (most recent call last):
547 ConfigParser.NoOptionError: No option 'does-not-exist' in section: 'mysqld'