"""Configuration file parser.

A setup file consists of sections, lead by a "[section]" header,

and followed by "name: value" entries, with continuations and such in

the style of RFC 822.

The option values can contain format strings which refer to other values in

the same section, or values in a special [DEFAULT] section.

For example:

something: %(dir)s/whatever

would resolve the "%(dir)s" to the value of dir. All reference

expansions are done late, on demand.

Intrinsic defaults can be specified by passing them into the

ConfigParser constructor as a dictionary.

class:

ConfigParser -- responsible for for parsing a list of

configuration files, and managing the parsed database.

methods:

__init__(defaults=None)

create the parser and specify a dictionary of intrinsic defaults. The

keys must be strings, the values must be appropriate for %()s string

interpolation. Note that `__name__' is always an intrinsic default;

it's value is the section's name.

sections()

return all the configuration section names, sans DEFAULT

has_section(section)

return whether the given section exists

has_option(section, option)

return whether the given option exists in the given section

options(section)

return list of configuration options for the named section

read(filenames)

read and parse the list of named configuration files, given by

name. A single filename is also allowed. Non-existing files

are ignored.

readfp(fp, filename=None)

read and parse one configuration file, given as a file object.

The filename defaults to fp.name; it is only used in error

messages (if fp has no `name' attribute, the string `<???>' is used).

get(section, option, raw=0, vars=None)

return a string value for the named option. All % interpolations are

expanded in the return values, based on the defaults passed into the

constructor and the DEFAULT section. Additional substitutions may be

provided using the `vars' argument, which must be a dictionary whose

contents override any pre-existing defaults.

getint(section, options)

like get(), but convert value to an integer

getfloat(section, options)

like get(), but convert value to a float

getboolean(section, options)

like get(), but convert value to a boolean (currently case

insensitively defined as 0, false, no, off for 0, and 1, true,

yes, on for 1). Returns 0 or 1.

remove_section(section)

remove the given file section and all its options

remove_option(section, option)

remove the given option from the given section

set(section, option, value)

set the given option

write(fp)

write the configuration state in .ini format

"""

import types

import re

__all__ = ["NoSectionError","DuplicateSectionError","NoOptionError",

"InterpolationError","InterpolationDepthError","ParsingError",

"MissingSectionHeaderError","ConfigParser",

"MAX_INTERPOLATION_DEPTH"]

DEFAULTSECT = "DEFAULT"

MAX_INTERPOLATION_DEPTH = 10

# exception classes

class Error(Exception):

def __init__(self, msg=''):

self._msg = msg

Exception.__init__(self, msg)

def __repr__(self):

return self._msg

__str__ = __repr__

class NoSectionError(Error):

def __init__(self, section):

Error.__init__(self, 'No section: %s' % section)

self.section = section

class DuplicateSectionError(Error):

def __init__(self, section):

Error.__init__(self, "Section %s already exists" % section)

self.section = section

class NoOptionError(Error):

def __init__(self, option, section):

Error.__init__(self, "No option `%s' in section: %s" %

(option, section))

self.option = option

self.section = section

class InterpolationError(Error):

def __init__(self, reference, option, section, rawval):

Error.__init__(self,

"Bad value substitution:\n"

"\tsection: [%s]\n"

"\toption : %s\n"

"\tkey : %s\n"

"\trawval : %s\n"

% (section, option, reference, rawval))

self.reference = reference

self.option = option

self.section = section

class InterpolationDepthError(Error):

def __init__(self, option, section, rawval):

Error.__init__(self,

"Value interpolation too deeply recursive:\n"

"\tsection: [%s]\n"

"\toption : %s\n"

"\trawval : %s\n"

% (section, option, rawval))

self.option = option

self.section = section

class ParsingError(Error):

def __init__(self, filename):

Error.__init__(self, 'File contains parsing errors: %s' % filename)

self.filename = filename

self.errors = []

def append(self, lineno, line):

self.errors.append((lineno, line))

self._msg = self._msg + '\n\t[line %2d]: %s' % (lineno, line)

class MissingSectionHeaderError(ParsingError):

def __init__(self, filename, lineno, line):

Error.__init__(

self,

'File contains no section headers.\nfile: %s, line: %d\n%s' %

(filename, lineno, line))

self.filename = filename

self.lineno = lineno

self.line = line

class ConfigParser:

def __init__(self, defaults=None):

self.__sections = {}

if defaults is None:

self.__defaults = {}

else:

self.__defaults = defaults

def defaults(self):

return self.__defaults

def sections(self):

"""Return a list of section names, excluding [DEFAULT]"""

# self.__sections will never have [DEFAULT] in it

return self.__sections.keys()

def add_section(self, section):

"""Create a new section in the configuration.

Raise DuplicateSectionError if a section by the specified name

already exists.

"""

if section in self.__sections:

raise DuplicateSectionError(section)

self.__sections[section] = {}

def has_section(self, section):

"""Indicate whether the named section is present in the configuration.

The DEFAULT section is not acknowledged.

"""

return section in self.sections()

def options(self, section):

"""Return a list of option names for the given section name."""

try:

opts = self.__sections[section].copy()

except KeyError:

raise NoSectionError(section)

opts.update(self.__defaults)

if '__name__' in opts:

del opts['__name__']

return opts.keys()

def read(self, filenames):

"""Read and parse a filename or a list of filenames.

Files that cannot be opened are silently ignored; this is

designed so that you can specify a list of potential

configuration file locations (e.g. current directory, user's

home directory, systemwide directory), and all existing

configuration files in the list will be read. A single

filename may also be given.

"""

if isinstance(filenames, basestring):

filenames = [filenames]

for filename in filenames:

try:

fp = open(filename)

except IOError:

continue

self.__read(fp, filename)

fp.close()

def readfp(self, fp, filename=None):

"""Like read() but the argument must be a file-like object.

The `fp' argument must have a `readline' method. Optional

second argument is the `filename', which if not given, is

taken from fp.name. If fp has no `name' attribute, `<???>' is

used.

"""

if filename is None:

try:

filename = fp.name

except AttributeError:

filename = '<???>'

self.__read(fp, filename)

def get(self, section, option, raw=0, vars=None):

"""Get an option value for a given section.

All % interpolations are expanded in the return values, based on the

defaults passed into the constructor, unless the optional argument

`raw' is true. Additional substitutions may be provided using the

`vars' argument, which must be a dictionary whose contents overrides

any pre-existing defaults.

The section DEFAULT is special.

"""

try:

sectdict = self.__sections[section].copy()

except KeyError:

if section == DEFAULTSECT:

sectdict = {}

else:

raise NoSectionError(section)

d = self.__defaults.copy()

d.update(sectdict)

# Update with the entry specific variables

if vars is not None:

d.update(vars)

option = self.optionxform(option)

try:

rawval = d[option]

except KeyError:

raise NoOptionError(option, section)

if raw:

return rawval

# do the string interpolation

value = rawval # Make it a pretty variable name

depth = 0

while depth < 10: # Loop through this until it's done

depth = depth + 1

if value.find("%(") >= 0:

try:

value = value % d

except KeyError, key:

raise InterpolationError(key, option, section, rawval)

else:

break

if value.find("%(") >= 0:

raise InterpolationDepthError(option, section, rawval)

return value

def __get(self, section, conv, option):

return conv(self.get(section, option))

def getint(self, section, option):

return self.__get(section, int, option)

def getfloat(self, section, option):

return self.__get(section, float, option)

def getboolean(self, section, option):

states = {'1': 1, 'yes': 1, 'true': 1, 'on': 1,

'0': 0, 'no': 0, 'false': 0, 'off': 0}

v = self.get(section, option)

if not v.lower() in states:

raise ValueError, 'Not a boolean: %s' % v

return states[v.lower()]

def optionxform(self, optionstr):

return optionstr.lower()

def has_option(self, section, option):

"""Check for the existence of a given option in a given section."""

if not section or section == "DEFAULT":

return option in self.__defaults

elif not self.has_section(section):

return 0

else:

option = self.optionxform(option)

return option in self.__sections[section]

def set(self, section, option, value):

"""Set an option."""

if not section or section == "DEFAULT":

sectdict = self.__defaults

else:

try:

sectdict = self.__sections[section]

except KeyError:

raise NoSectionError(section)

option = self.optionxform(option)

sectdict[option] = value

def write(self, fp):

"""Write an .ini-format representation of the configuration state."""

if self.__defaults:

fp.write("[DEFAULT]\n")

for (key, value) in self.__defaults.items():

fp.write("%s = %s\n" % (key, str(value).replace('\n', '\n\t')))

fp.write("\n")

for section in self.sections():

fp.write("[" + section + "]\n")

sectdict = self.__sections[section]

for (key, value) in sectdict.items():

if key == "__name__":

continue

fp.write("%s = %s\n" % (key, str(value).replace('\n', '\n\t')))

fp.write("\n")

def remove_option(self, section, option):

"""Remove an option."""

if not section or section == "DEFAULT":

sectdict = self.__defaults

else:

try:

sectdict = self.__sections[section]

except KeyError:

raise NoSectionError(section)

option = self.optionxform(option)

existed = option in sectdict

if existed:

del sectdict[option]

return existed

def remove_section(self, section):

"""Remove a file section."""

if section in self.__sections:

del self.__sections[section]

return True

else:

return False

#

# Regular expressions for parsing section headers and options. Note a

# slight semantic change from the previous version, because of the use

# of \w, _ is allowed in section header names.

SECTCRE = re.compile(

r'\[' # [

r'(?P<header>[^]]+)' # very permissive!

r'\]' # ]

)

OPTCRE = re.compile(

r'(?P<option>[]\-[\w_.*,(){}]+)' # a lot of stuff found by IvL

r'[ \t]*(?P<vi>[:=])[ \t]*' # any number of space/tab,

# followed by separator

# (either : or =), followed

# by any # space/tab

r'(?P<value>.*)$' # everything up to eol

)

def __read(self, fp, fpname):

"""Parse a sectioned setup file.

The sections in setup file contains a title line at the top,

indicated by a name in square brackets (`[]'), plus key/value

options lines, indicated by `name: value' format lines.

Continuation are represented by an embedded newline then

leading whitespace. Blank lines, lines beginning with a '#',

and just about everything else is ignored.

"""

cursect = None # None, or a dictionary

optname = None

lineno = 0

e = None # None, or an exception

while 1:

line = fp.readline()

if not line:

break

lineno = lineno + 1

# comment or blank line?

if line.strip() == '' or line[0] in '#;':

continue

if line.split()[0].lower() == 'rem' \

and line[0] in "rR": # no leading whitespace

continue

# continuation line?

if line[0] in ' \t' and cursect is not None and optname:

value = line.strip()

if value:

k = self.optionxform(optname)

cursect[k] = "%s\n%s" % (cursect[k], value)

# a section header or option header?

else:

# is it a section header?

mo = self.SECTCRE.match(line)

if mo:

sectname = mo.group('header')

if sectname in self.__sections:

cursect = self.__sections[sectname]

elif sectname == DEFAULTSECT:

cursect = self.__defaults

else:

cursect = {'__name__': sectname}

self.__sections[sectname] = cursect

# So sections can't start with a continuation line

optname = None

# no section header in the file?

elif cursect is None:

raise MissingSectionHeaderError(fpname, lineno, `line`)

# an option line?

else:

mo = self.OPTCRE.match(line)

if mo:

optname, vi, optval = mo.group('option', 'vi', 'value')

if vi in ('=', ':') and ';' in optval:

# ';' is a comment delimiter only if it follows

# a spacing character

pos = optval.find(';')

if pos and optval[pos-1].isspace():

optval = optval[:pos]

optval = optval.strip()

# allow empty values

if optval == '""':

optval = ''

cursect[self.optionxform(optname)] = optval

else:

# a non-fatal parsing error occurred. set up the

# exception but keep going. the exception will be

# raised at the end of the file and will contain a

# list of all bogus lines

if not e:

e = ParsingError(fpname)

e.append(lineno, `line`)

# if any parsing errors occurred, raise an exception

if e:

raise e