| :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 provides the classes :class:`RawConfigParser` and |
| :class:`SafeConfigParser`. They implement a basic configuration file parser |
| language which provides a structure similar to what you would find in 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. |
| |
| A configuration file consists of sections, each led by a ``[section]`` header, |
| followed by name/value entries separated by a specific string (``=`` or ``:`` by |
| default). Note that leading whitespace is removed from values. Values can be |
| ommitted, in which case the key/value delimiter may also be left out. Values |
| can also span multiple lines, as long as they are indented deeper than the first |
| line of the value. Depending on the parser's mode, blank lines may be treated |
| as parts of multiline values or ignored. |
| |
| Configuration files may include comments, prefixed by specific characters (``#`` |
| and ``;`` by default). 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, by default 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:: |
| |
| [Paths] |
| home_dir: /Users |
| my_dir: %(home_dir)s/lumberjack |
| my_pictures: %(my_dir)s/Pictures |
| |
| [Multiline Values] |
| chorus: I'm a lumberjack, and I'm okay |
| I sleep all night and I work all day |
| |
| [No Values] |
| key_without_value |
| empty string value here = |
| |
| [You can use comments] ; after a useful line |
| ; in an empty line |
| after: a_value ; here's another comment |
| inside: a ;comment |
| multiline ;comment |
| value! ;comment |
| |
| [Sections Can Be Indented] |
| can_values_be_as_well = True |
| does_that_mean_anything_special = False |
| purpose = formatting for readability |
| multiline_values = are |
| handled just fine as |
| long as they are indented |
| deeper than the first line |
| of a value |
| # Did I mention we can indent comments, too? |
| |
| |
| In the example above, :class:`SafeConfigParser` would resolve ``%(home_dir)s`` |
| to the value of ``home_dir`` (``/Users`` in this case). ``%(my_dir)s`` in |
| effect would resolve to ``/Users/lumberjack``. All interpolations are done on |
| demand so keys used in the chain of references do not have to be specified in |
| any specific order in the configuration file. |
| |
| :class:`RawConfigParser` would simply return ``%(my_dir)s/Pictures`` as the |
| value of ``my_pictures`` and ``%(home_dir)s/lumberjack`` as the value of |
| ``my_dir``. Other features presented in the example are handled in the same |
| manner by both parsers. |
| |
| Default values can be specified by passing them as a dictionary when |
| constructing the :class:`SafeConfigParser`. |
| |
| Sections are normally stored in an :class:`collections.OrderedDict` which |
| maintains the order of all keys. An alternative dictionary type can be passed |
| to the :meth:`__init__` method. 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, delimiters=('=', ':'), comment_prefixes=_COMPATIBLE, empty_lines_in_values=True, allow_no_value=False) |
| |
| 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. |
| |
| When *delimiters* is given, it will be used as the set of substrings that |
| divide keys from values. When *comment_prefixes* is given, it will be used |
| as the set of substrings that prefix comments in a line, both for the whole |
| line and inline comments. For backwards compatibility, the default value for |
| *comment_prefixes* is a special value that indicates that ``;`` and ``#`` can |
| start whole line comments while only ``;`` can start inline comments. |
| |
| When *empty_lines_in_values* is ``False`` (default: ``True``), each empty |
| line marks the end of an option. Otherwise, internal empty lines of a |
| multiline option are kept as part of the value. When *allow_no_value* is |
| true (default: ``False``), options without values are accepted; the value |
| presented for these is ``None``. |
| |
| This class does not support the magical interpolation behavior. |
| |
| .. versionchanged:: 3.1 |
| The default *dict_type* is :class:`collections.OrderedDict`. |
| |
| .. versionchanged:: 3.2 |
| *delimiters*, *comment_prefixes*, *empty_lines_in_values* and |
| *allow_no_value* were added. |
| |
| |
| .. class:: SafeConfigParser(defaults=None, dict_type=collections.OrderedDict, delimiters=('=', ':'), comment_prefixes=('#', ';'), empty_lines_in_values=True, allow_no_value=False) |
| |
| Derived class of :class:`ConfigParser` that implements a sane variant of the |
| magical interpolation feature. This implementation is more predictable as it |
| validates the interpolation syntax used within a configuration file. This |
| class also enables escaping the interpolation character (e.g. a key can have |
| ``%`` as part of the value by specifying ``%%`` in the file). |
| |
| Applications that don't require interpolation should use |
| :class:`RawConfigParser`, otherwise :class:`SafeConfigParser` is the best |
| option. |
| |
| .. versionchanged:: 3.1 |
| The default *dict_type* is :class:`collections.OrderedDict`. |
| |
| .. versionchanged:: 3.2 |
| *delimiters*, *comment_prefixes*, *empty_lines_in_values* and |
| *allow_no_value* were added. |
| |
| |
| .. class:: ConfigParser(defaults=None, dict_type=collections.OrderedDict, delimiters=('=', ':'), comment_prefixes=('#', ';'), empty_lines_in_values=True, allow_no_value=False) |
| |
| Derived class of :class:`RawConfigParser` that implements the magical |
| interpolation feature and adds optional arguments to the :meth:`get` and |
| :meth:`items` methods. |
| |
| :class:`SafeConfigParser` is generally recommended over this class if you |
| need interpolation. |
| |
| 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`. |
| |
| .. versionchanged:: 3.2 |
| *delimiters*, *comment_prefixes*, *empty_lines_in_values* and |
| *allow_no_value* were added. |
| |
| |
| .. 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, encoding=None) |
| |
| 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')], encoding='cp1250') |
| |
| .. versionadded:: 3.2 |
| The *encoding* parameter. Previously, all files were read using the |
| default encoding for :func:`open`. |
| |
| |
| .. 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, space_around_delimiters=True) |
| |
| 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. If ``space_around_delimiters`` |
| is ``True`` (the default), delimiters between keys and values are surrounded |
| by spaces. |
| |
| |
| .. 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. Whenever you |
| can, consider using :class:`SafeConfigParser` which adds validation and escaping |
| for the interpolation. |
| |
| |
| .. 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) |
| |
| Some configuration files are known to include settings without values, but which |
| otherwise conform to the syntax supported by :mod:`configparser`. The |
| *allow_no_value* parameter to the :meth:`__init__` method can be used to |
| indicate that such values should be accepted: |
| |
| .. doctest:: |
| |
| >>> import configparser |
| >>> import io |
| |
| >>> sample_config = """ |
| ... [mysqld] |
| ... user = mysql |
| ... pid-file = /var/run/mysqld/mysqld.pid |
| ... skip-external-locking |
| ... old_passwords = 1 |
| ... skip-bdb |
| ... skip-innodb # we don't need ACID today |
| ... """ |
| >>> config = configparser.RawConfigParser(allow_no_value=True) |
| >>> config.readfp(io.BytesIO(sample_config)) |
| |
| >>> # Settings with values are treated as before: |
| >>> config.get("mysqld", "user") |
| 'mysql' |
| |
| >>> # Settings without values provide None: |
| >>> config.get("mysqld", "skip-bdb") |
| |
| >>> # Settings which aren't specified still raise an error: |
| >>> config.get("mysqld", "does-not-exist") |
| Traceback (most recent call last): |
| ... |
| configparser.NoOptionError: No option 'does-not-exist' in section: 'mysqld' |