311 lines
11 KiB
Python
311 lines
11 KiB
Python
"""Configuration file parser.
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A setup file consists of sections, lead by a "[section]" header,
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and followed by "name: value" entries, with continuations and such in
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the style of RFC 822.
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The option values can contain format strings which refer to other values in
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the same section, or values in a special [DEFAULT] section.
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For example:
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something: %(dir)s/whatever
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would resolve the "%(dir)s" to the value of dir. All reference
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expansions are done late, on demand.
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Intrinsic defaults can be specified by passing them into the
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ConfigParser constructor as a dictionary.
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class:
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ConfigParser -- responsible for for parsing a list of
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configuration files, and managing the parsed database.
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methods:
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__init__(defaults=None) -- create the parser and specify a
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dictionary of intrinsic defaults. The
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keys must be strings, the values must
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be appropriate for %()s string
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interpolation. Note that `__name__' is
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always an intrinsic default; it's value
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is the section's name.
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sections() -- return all the configuration section names, sans DEFAULT
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options(section) -- return list of configuration options for the named
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section
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read(*filenames) -- read and parse the list of named configuration files
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get(section, option, raw=0) -- return a string value for the named
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option. All % interpolations are
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expanded in the return values, based on
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the defaults passed into the constructor
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and the DEFAULT section.
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getint(section, options) -- like get(), but convert value to an integer
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getfloat(section, options) -- like get(), but convert value to a float
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getboolean(section, options) -- like get(), but convert value to
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a boolean (currently defined as 0
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or 1, only)
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"""
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import sys
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import string
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import re
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DEFAULTSECT = "DEFAULT"
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# exception classes
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class Error:
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def __init__(self, msg=''):
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self._msg = msg
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def __repr__(self):
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return self._msg
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class NoSectionError(Error):
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def __init__(self, section):
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Error.__init__(self, 'No section: %s' % section)
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self.section = section
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class DuplicateSectionError(Error):
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def __init__(self, section):
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Error.__init__(self, "Section %s already exists" % section)
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self.section = section
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class NoOptionError(Error):
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def __init__(self, option, section):
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Error.__init__(self, "No option `%s' in section: %s" %
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(option, section))
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self.option = option
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self.section = section
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class InterpolationError(Error):
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def __init__(self, reference, option, section, rawval):
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Error.__init__(self,
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"Bad value substitution:\n"
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"\tsection: [%s]\n"
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"\toption : %s\n"
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"\tkey : %s\n"
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"\trawval : %s\n"
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% (section, option, reference, rawval))
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self.reference = reference
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self.option = option
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self.section = section
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class MissingSectionHeaderError(Error):
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def __init__(self, filename, lineno, line):
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Error.__init__(
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self,
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'File contains no section headers.\nfile: %s, line: %d\n%s' %
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(filename, lineno, line))
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self.filename = filename
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self.lineno = lineno
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self.line = line
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class ParsingError(Error):
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def __init__(self, filename):
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Error.__init__(self, 'File contains parsing errors: %s' % filename)
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self.filename = filename
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self.errors = []
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def append(self, lineno, line):
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self.errors.append((lineno, line))
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self._msg = self._msg + '\n\t[line %2d]: %s' % (lineno, line)
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class ConfigParser:
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def __init__(self, defaults=None):
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self.__sections = {}
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if defaults is None:
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self.__defaults = {}
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else:
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self.__defaults = defaults
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def defaults(self):
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return self.__defaults
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def sections(self):
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"""Return a list of section names, excluding [DEFAULT]"""
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# self.__sections will never have [DEFAULT] in it
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return self.__sections.keys()
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def add_section(self, section):
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"""Create a new section in the configuration.
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Raise DuplicateSectionError if a section by the specified name
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already exists.
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"""
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if self.__sections.has_key(section):
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raise DuplicateSectionError(section)
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self.__sections[section] = {}
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def has_section(self, section):
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"""Indicate whether the named section is present in the configuration.
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The DEFAULT section is not acknowledged.
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"""
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return self.__sections.has_key(section)
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def options(self, section):
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try:
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opts = self.__sections[section].copy()
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except KeyError:
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raise NoSectionError(section)
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opts.update(self.__defaults)
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return opts.keys()
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def read(self, filenames):
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"""Read and parse a list of filenames."""
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if type(filenames) is type(''):
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filenames = [filenames]
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for file in filenames:
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try:
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fp = open(file, 'r')
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self.__read(fp)
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except IOError:
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pass
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def get(self, section, option, raw=0):
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"""Get an option value for a given section.
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All % interpolations are expanded in the return values, based
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on the defaults passed into the constructor, unless the optional
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argument `raw' is true.
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The section DEFAULT is special.
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"""
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try:
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sectdict = self.__sections[section].copy()
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except KeyError:
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if section == DEFAULTSECT:
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sectdict = {}
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else:
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raise NoSectionError(section)
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d = self.__defaults.copy()
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d.update(sectdict)
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option = string.lower(option)
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try:
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rawval = d[option]
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except KeyError:
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raise NoOptionError(option, section)
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# do the string interpolation
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if raw:
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return rawval
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try:
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return rawval % d
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except KeyError, key:
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raise InterpolationError(key, option, section, rawval)
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def __get(self, section, conv, option):
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return conv(self.get(section, option))
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def getint(self, section, option):
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return self.__get(section, string.atoi, option)
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def getfloat(self, section, option):
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return self.__get(section, string.atof, option)
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def getboolean(self, section, option):
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v = self.get(section, option)
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val = string.atoi(v)
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if val not in (0, 1):
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raise ValueError, 'Not a boolean: %s' % v
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return val
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#
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# Regular expressions for parsing section headers and options. Note a
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# slight semantic change from the previous version, because of the use
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# of \w, _ is allowed in section header names.
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__SECTCRE = re.compile(
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r'\[' # [
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r'(?P<header>[-\w]+)' # `-', `_' or any alphanum
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r'\]' # ]
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)
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__OPTCRE = re.compile(
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r'(?P<option>[-.\w]+)' # - . _ alphanum
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r'[ \t]*[:=][ \t]*' # any number of space/tab,
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# followed by separator
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# (either : or =), followed
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# by any # space/tab
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r'(?P<value>.*)$' # everything up to eol
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)
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def __read(self, fp):
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"""Parse a sectioned setup file.
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The sections in setup file contains a title line at the top,
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indicated by a name in square brackets (`[]'), plus key/value
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options lines, indicated by `name: value' format lines.
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Continuation are represented by an embedded newline then
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leading whitespace. Blank lines, lines beginning with a '#',
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and just about everything else is ignored.
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"""
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cursect = None # None, or a dictionary
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optname = None
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lineno = 0
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e = None # None, or an exception
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while 1:
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line = fp.readline()
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if not line:
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break
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lineno = lineno + 1
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# comment or blank line?
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if string.strip(line) == '' or line[0] in '#;':
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continue
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if string.lower(string.split(line)[0]) == 'rem' \
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and line[0] == "r": # no leading whitespace
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continue
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# continuation line?
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if line[0] in ' \t' and cursect is not None and optname:
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value = string.strip(line)
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if value:
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cursect[optname] = cursect[optname] + '\n ' + value
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# a section header or option header?
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else:
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# is it a section header?
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mo = self.__SECTCRE.match(line)
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if mo:
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sectname = mo.group('header')
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if self.__sections.has_key(sectname):
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cursect = self.__sections[sectname]
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elif sectname == DEFAULTSECT:
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cursect = self.__defaults
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else:
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cursect = {'__name__': sectname}
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self.__sections[sectname] = cursect
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# So sections can't start with a continuation line
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optname = None
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# no section header in the file?
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elif cursect is None:
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raise MissingSectionHeaderError(fp.name, lineno, `line`)
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# an option line?
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else:
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mo = self.__OPTCRE.match(line)
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if mo:
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optname, optval = mo.group('option', 'value')
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optname = string.lower(optname)
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optval = string.strip(optval)
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# allow empty values
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if optval == '""':
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optval = ''
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cursect[optname] = optval
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else:
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# a non-fatal parsing error occurred. set up the
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# exception but keep going. the exception will be
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# raised at the end of the file and will contain a
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# list of all bogus lines
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if not e:
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e = ParsingError(fp.name)
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e.append(lineno, `line`)
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# if any parsing errors occurred, raise an exception
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if e:
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raise e
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