| :mod:`configparser` --- Configuration file parser |
| ================================================= |
| |
| .. module:: configparser |
| :synopsis: Configuration file parser. |
| |
| .. 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> |
| |
| .. 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. |
| |
| .. note:: |
| |
| 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. |
| |
| Configuration files may include comments, prefixed by specific characters (``#`` |
| and ``;``). Comments may appear on their own in an otherwise empty line, or may |
| be entered in lines holding values or spection names. In the latter case, they |
| need to be preceded by a whitespace character to be recognized as a comment. |
| (For backwards compatibility, only ``;`` starts an inline comment, while ``#`` |
| does not.) |
| |
| On top of the core functionality, :class:`SafeConfigParser` supports |
| interpolation. This means 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. |
| |
| For example:: |
| |
| [My Section] |
| foodir: %(dir)s/whatever |
| dir=frob |
| long: this value continues |
| in the next line |
| |
| 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 built-in 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=None, dict_type=collections.OrderedDict) |
| |
| 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. |
| |
| .. versionchanged:: 3.1 |
| The default *dict_type* is :class:`collections.OrderedDict`. |
| |
| |
| .. class:: ConfigParser(defaults=None, dict_type=collections.OrderedDict) |
| |
| 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. |
| |
| .. versionchanged:: 3.1 |
| The default *dict_type* is :class:`collections.OrderedDict`. |
| |
| |
| .. class:: SafeConfigParser(defaults=None, dict_type=collections.OrderedDict) |
| |
| 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. |
| |
| .. XXX Need to explain what's safer/more predictable about it. |
| |
| .. versionchanged:: 3.1 |
| The default *dict_type* is :class:`collections.OrderedDict`. |
| |
| |
| .. exception:: Error |
| |
| Base class for all other configparser exceptions. |
| |
| |
| .. 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`. |
| |
| |
| .. exception:: InterpolationSyntaxError |
| |
| Exception raised when the source text into which substitutions are made does not |
| conform to the required syntax. Subclass of :exc:`InterpolationError`. |
| |
| |
| .. 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. |
| |
| .. 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`. |
| |
| |
| .. 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, |
| 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 |
| |
| config = configparser.ConfigParser() |
| config.readfp(open('defaults.cfg')) |
| config.read(['site.cfg', os.path.expanduser('~/.myapp.cfg')]) |
| |
| |
| .. method:: RawConfigParser.readfp(fp, filename=None) |
| |
| Read and parse configuration data from the file or file-like object in *fp* |
| (only the :meth:`readline` method is used). The file-like object must |
| operate in text mode, i.e. return strings from :meth:`readline`. |
| |
| 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. |
| |
| |
| .. method:: RawConfigParser.write(fileobject) |
| |
| Write a representation of the configuration to the specified file object, |
| which must be opened in text mode (accepting strings). This representation |
| can be parsed by a future :meth:`read` call. |
| |
| |
| .. 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`. |
| |
| |
| .. 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. |
| |
| You don't necessarily need to subclass a ConfigParser to use this method, you |
| can also re-set it on an instance, to a function that takes a string |
| argument. Setting it to ``str``, for example, would make option names case |
| sensitive:: |
| |
| cfgparser = ConfigParser() |
| ... |
| cfgparser.optionxform = str |
| |
| Note that when reading configuration files, whitespace around the |
| option names are stripped before :meth:`optionxform` is called. |
| |
| |
| .. _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=False, vars=None) |
| |
| Get an *option* value for the named *section*. If *vars* is provided, it |
| must be a dictionary. The *option* is looked up in *vars* (if provided), |
| *section*, and in *defaults* in that order. |
| |
| All the ``'%'`` interpolations are expanded in the return values, unless the |
| *raw* argument is true. Values for interpolation keys are looked up in the |
| same manner as the option. |
| |
| |
| .. method:: ConfigParser.items(section, raw=False, vars=None) |
| |
| 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. |
| |
| |
| .. _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; if it is |
| not, :exc:`TypeError` is raised. |
| |
| |
| 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', 'w') 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) |
| else: |
| config.remove_option(section1, option) |