Doc/lib/libcfgparser.tex

   1 \section{\module{ConfigParser} ---
   2          Configuration file parser}
   3
   4 \declaremodule{standard}{ConfigParser}
   5 \modulesynopsis{Configuration file parser.}
   6 \moduleauthor{Ken Manheimer}{klm@digicool.com}
   7 \moduleauthor{Barry Warsaw}{bwarsaw@python.org}
   8 \moduleauthor{Eric S. Raymond}{esr@thyrsus.com}
   9 \sectionauthor{Christopher G. Petrilli}{petrilli@amber.org}
  10
  11 This module defines the class \class{ConfigParser}.
  12 \indexii{.ini}{file}\indexii{configuration}{file}\index{ini file}
  13 \index{Windows ini file}
  14 The \class{ConfigParser} class implements a basic configuration file
  15 parser language which provides a structure similar to what you would
  16 find on Microsoft Windows INI files.  You can use this to write Python
  17 programs which can be customized by end users easily.
  18
  19 The configuration file consists of sections, lead by a
  20 \samp{[section]} header and followed by \samp{name: value} entries,
  21 with continuations in the style of \rfc{822}; \samp{name=value} is
  22 also accepted.  Note that leading whitespace is removed from values.
  23 The optional values can contain format strings which refer to other
  24 values in the same section, or values in a special
  25 \code{DEFAULT} section.  Additional defaults can be provided upon
  26 initialization and retrieval.  Lines beginning with \character{\#} or
  27 \character{;} are ignored and may be used to provide comments.
  28
  29 For example:
  30
  31 \begin{verbatim}
  32 foodir: %(dir)s/whatever
  33 dir=frob
  34 \end{verbatim}
  35
  36 would resolve the \samp{\%(dir)s} to the value of
  37 \samp{dir} (\samp{frob} in this case).  All reference expansions are
  38 done on demand.
  39
  40 Default values can be specified by passing them into the
  41 \class{ConfigParser} constructor as a dictionary.  Additional defaults
  42 may be passed into the \method{get()} method which will override all
  43 others.
  44
  45 \begin{classdesc}{ConfigParser}{\optional{defaults}}
  46 Return a new instance of the \class{ConfigParser} class.  When
  47 \var{defaults} is given, it is initialized into the dictionary of
  48 intrinsic defaults.  The keys must be strings, and the values must be
  49 appropriate for the \samp{\%()s} string interpolation.  Note that
  50 \var{__name__} is an intrinsic default; its value is the section name,
  51 and will override any value provided in \var{defaults}.
  52 \end{classdesc}
  53
  54 \begin{excdesc}{NoSectionError}
  55 Exception raised when a specified section is not found.
  56 \end{excdesc}
  57
  58 \begin{excdesc}{DuplicateSectionError}
  59 Exception raised when multiple sections with the same name are found,
  60 or if \method{add_section()} is called with the name of a section that
  61 is already present.
  62 \end{excdesc}
  63
  64 \begin{excdesc}{NoOptionError}
  65 Exception raised when a specified option is not found in the specified
  66 section.
  67 \end{excdesc}
  68
  69 \begin{excdesc}{InterpolationError}
  70 Exception raised when problems occur performing string interpolation.
  71 \end{excdesc}
  72
  73 \begin{excdesc}{InterpolationDepthError}
  74 Exception raised when string interpolation cannot be completed because
  75 the number of iterations exceeds \constant{MAX_INTERPOLATION_DEPTH}.
  76 \end{excdesc}
  77
  78 \begin{excdesc}{MissingSectionHeaderError}
  79 Exception raised when attempting to parse a file which has no section
  80 headers.
  81 \end{excdesc}
  82
  83 \begin{excdesc}{ParsingError}
  84 Exception raised when errors occur attempting to parse a file.
  85 \end{excdesc}
  86
  87 \begin{datadesc}{MAX_INTERPOLATION_DEPTH}
  88 The maximum depth for recursive interpolation for \method{get()} when
  89 the \var{raw} parameter is false.  Setting this does not change the
  90 allowed recursion depth.
  91 \end{datadesc}
  92
  93
  94 \begin{seealso}
  95   \seemodule{shlex}{Support for a creating \UNIX{} shell-like
  96                     minilanguages which can be used as an alternate format
  97                     for application configuration files.}
  98 \end{seealso}
  99
 100
 101 \subsection{ConfigParser Objects \label{ConfigParser-objects}}
 102
 103 \class{ConfigParser} instances have the following methods:
 104
 105 \begin{methoddesc}{defaults}{}
 106 Return a dictionary containing the instance-wide defaults.
 107 \end{methoddesc}
 108
 109 \begin{methoddesc}{sections}{}
 110 Return a list of the sections available; \code{DEFAULT} is not
 111 included in the list.
 112 \end{methoddesc}
 113
 114 \begin{methoddesc}{add_section}{section}
 115 Add a section named \var{section} to the instance.  If a section by
 116 the given name already exists, \exception{DuplicateSectionError} is
 117 raised.
 118 \end{methoddesc}
 119
 120 \begin{methoddesc}{has_section}{section}
 121 Indicates whether the named section is present in the
 122 configuration. The \code{DEFAULT} section is not acknowledged.
 123 \end{methoddesc}
 124
 125 \begin{methoddesc}{options}{section}
 126 Returns a list of options available in the specified \var{section}.
 127 \end{methoddesc}
 128
 129 \begin{methoddesc}{has_option}{section, option}
 130 If the given section exists, and contains the given option. return 1;
 131 otherwise return 0. (New in 1.6)
 132 \end{methoddesc}
 133
 134 \begin{methoddesc}{read}{filenames}
 135 Read and parse a list of filenames.  If \var{filenames} is a string or
 136 Unicode string, it is treated as a single filename.
 137 \end{methoddesc}
 138
 139 \begin{methoddesc}{readfp}{fp\optional{, filename}}
 140 Read and parse configuration data from the file or file-like object in
 141 \var{fp} (only the \method{readline()} method is used).  If
 142 \var{filename} is omitted and \var{fp} has a \member{name} attribute,
 143 that is used for \var{filename}; the default is \samp{<???>}.
 144 \end{methoddesc}
 145
 146 \begin{methoddesc}{get}{section, option\optional{, raw\optional{, vars}}}
 147 Get an \var{option} value for the provided \var{section}.  All the
 148 \character{\%} interpolations are expanded in the return values, based on
 149 the defaults passed into the constructor, as well as the options
 150 \var{vars} provided, unless the \var{raw} argument is true.
 151 \end{methoddesc}
 152
 153 \begin{methoddesc}{getint}{section, option}
 154 A convenience method which coerces the \var{option} in the specified
 155 \var{section} to an integer.
 156 \end{methoddesc}
 157
 158 \begin{methoddesc}{getfloat}{section, option}
 159 A convenience method which coerces the \var{option} in the specified
 160 \var{section} to a floating point number.
 161 \end{methoddesc}
 162
 163 \begin{methoddesc}{getboolean}{section, option}
 164 A convenience method which coerces the \var{option} in the specified
 165 \var{section} to a boolean value.  Note that the only accepted values
 166 for the option are \samp{0} and \samp{1}, any others will raise
 167 \exception{ValueError}.
 168 \end{methoddesc}
 169
 170 \begin{methoddesc}{set}{section, option, value}
 171 If the given section exists, set the given option to the specified value;
 172 otherwise raise \exception{NoSectionError}. (New in 1.6)
 173 \end{methoddesc}
 174
 175 \begin{methoddesc}{write}{fileobject}
 176 Write a representation of the configuration to the specified file
 177 object.  This representation can be parsed by a future \method{read()}
 178 call. (New in 1.6)
 179 \end{methoddesc}
 180
 181 \begin{methoddesc}{remove_option}{section, option}
 182 Remove the specified \var{option} from the specified \var{section}.
 183 If the section does not exist, raise \exception{NoSectionError}.
 184 If the option existed to be removed, return 1; otherwise return 0.
 185 (New in 1.6)
 186 \end{methoddesc}
 187
 188 \begin{methoddesc}{remove_section}{section}
 189 Remove the specified \var{section} from the configuration.
 190 If the section in fact existed, return 1.  Otherwise return 0.
 191 \end{methoddesc}
 192
 193 \begin{methoddesc}{optionxform}{option}
 194 Transforms the option name \var{option} as found in an input file or
 195 as passed in by  client code to the form that should be used in the
 196 internal structures.  The default implementation returns a lower-case
 197 version of \var{option}; subclasses may override this or client code
 198 can set an attribute of this name on instances to affect this
 199 behavior.  Setting this to \function{str()}, for example, would make
 200 option names case sensitive.
 201 \end{methoddesc}