PeterHarding at 06:05, 19 July 2009

2009-07-19T06:05:58Z

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	[[Category:Python]]		[[Category:Python]]
			[[Category:Examples]]

PeterHarding: New page:

 #!/usr/bin/python '''Configuration file parser for files similar to MS-Windows .ini files. Meant as a replacement for the broken ConfigParser module in the Python standard library.  ...

2008-05-24T07:04:41Z

New page: <pre> #!/usr/bin/python '''Configuration file parser for files similar to MS-Windows .ini files. Meant as a replacement for the broken ConfigParser module in the Python standard library. ...

New page

<pre>
#!/usr/bin/python
'''Configuration file parser for files similar to MS-Windows .ini files.
Meant as a replacement for the broken ConfigParser module in the Python
standard library.

Copyright (C) 2000 Charles Cazabon <getmail @ discworld.dyndns.org>

This program is free software; you can redistribute it and/or
modify it under the terms of version 2 of the GNU General Public License
as published by the Free Software Foundation. A copy of this license should
be included in the file COPYING.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

For documentation, see the Python standard module ConfigParser documentation.
This module is similar, except:
o Options are supplied with option_name=option_value pairs only (not ':').
o Comments are allowed on the same lines as data, with '#' as the comment
delimiter.
o Leading and trailing whitespace is ignored.
o Whitespace surrounding the '=' sign is ignored.
o Option values can be quoted with single or double quotes, to preserve
leading or trailing whitespace, or if they contain a whitespace or the
"#" symbol which would otherwise mark the start of a comment.
o Empty option values must be quoted; use the empty string ("" or '')
o Option values are returned as either:
o a string, if the option name occurs once in the section
o a list of strings, if the option name occurs multiple times
o All the limitations on what characters can be in section headers and
option values are gone, except that '#' is forbidden (because it
starts a comment), and option names cannot contain '=' (because that
starts a value).

I welcome questions and comments at <software @ discworld.dyndns.org>.
'''

__version__ = '3.1'
__author__ = 'Charles Cazabon <software @ discworld.dyndns.org>'

#
# Imports
#

import string
import UserDict
import sys
import shlex
import cStringIO
from types import *

#
# ConfParser exception classes
#

# Base class for all ConfParser exceptions
class ConfParserException (Exception):
pass

# Specific exceptions
class NoSectionError (ConfParserException):
'''Exception raised when a specified section is not found.
'''
pass

class DuplicateSectionError (ConfParserException):
'''Exception raised when mutliple sections with the same name are found, or
if add_section() is called with the name of a section that is already
present.
'''
pass

class NoOptionError (ConfParserException):
'''Exception raised when a specified option is not found in the specified
section.
'''
pass

class InterpolationError (ConfParserException):
'''Exception raised when problems occur performing string interpolation.
'''
pass

class MissingSectionHeaderError (ConfParserException):
'''Exception raised when attempting to parse a file which has no section
headers.
'''
pass

class ParsingError (ConfParserException):
'''Exception raised when errors occur attempting to parse a file.
Also raised if defaults is not a dictionary, or when reading a file fails.
These errors are not covered by exceptions in the standard Python
ConfigParser module.
'''
pass

#
# Globals
#

debug = 0

#
# Helper functions
#

#######################################
def log (msg):
if not debug: return
sys.stderr.write (msg + '\n')
sys.stderr.flush ()

#
# ConfParser SmartDict class
#

#######################################
class SmartDict (UserDict.UserDict):
'''Dictionary class which handles lists and singletons intelligently.
'''
#######################################
def __init__ (self, initialdata = {}):
'''Constructor.
'''
UserDict.UserDict.__init__ (self, {})
for (key, value) in initialdata.items ():
self.__setitem (key, value)

#######################################
def __getitem__ (self, key):
'''
'''
try:
value = self.data[key]
if len (value) == 1:
return value[0]
return value
except KeyError, txt:
raise KeyError, txt

#######################################
def __setitem__ (self, key, value):
'''
'''
if type (value) in (ListType, TupleType):
self.data[key] = list (value)
else:
self.data[key] = [value]

#
# Main ConfParser class
#

#######################################
class ConfParser:
'''Class to parse a configuration file without all the limitations in
ConfigParser.py, but without the dictionary formatting options either.
'''
#######################################
def __init__ (self, defaults = {}):
'''Constructor.
'''
self.__rawdata = []
self.__sectionlist = []
self.__sections = []
self.__defaults = SmartDict ()

try:
for key in defaults.keys ():
self.__defaults[key] = defaults[key]

except AttributeError:
raise ParsingError, 'defaults not a dictionary (%s)' % defaults

#######################################
def read (self, filelist):
'''Read configuration file(s) from list of 1 or more filenames.
'''
if type (filelist) not in (ListType, TupleType):
filelist = [filelist]

try:
for filename in filelist:
log ('Reading configuration file "%s"' % filename)
f = open (filename, 'r')
self.__rawdata = self.__rawdata + f.readlines ()
f.close ()

except IOError, txt:
raise ParsingError, 'error reading configuration file (%s)' % txt

self.__parse ()
return self

#######################################
def __parse (self):
'''Parse the read-in configuration file.
'''
config = string.join (self.__rawdata, '\n')
f = cStringIO.StringIO (config)
lex = shlex.shlex (f)
lex.wordchars = lex.wordchars + '|/.,$^\\():;@-+?<>!%&*`~'
section_name = ''
option_name = ''
option_value = ''

while 1:
token = lex.get_token ()
if token == '':
break

if not (section_name):
if token != '[':
raise ParsingError, 'expected section start, got %s' % token
section_name = ''
while 1:
token = lex.get_token ()
if token == ']':
break
if token == '':
raise ParsingError, 'expected section end, hit EOF'
if section_name:
section_name = section_name + ' '
section_name = section_name + token
if not section_name:
raise ParsingError, 'expected section name, got nothing'

section = SmartDict ()
# Collapse case on section names
section_name = string.lower (section_name)
if section_name in self.__sectionlist:
raise DuplicateSectionError, \
'duplicate section (%s)' % section_name
section['__name__'] = section_name
continue

if token == '=':
raise ParsingError, 'expected option name, got ='

if token == '[':
# Start new section
lex.push_token (token)
if section_name in self.__sectionlist:
raise DuplicateSectionError, \
'duplicate section (%s)' % section_name
if section['__name__'] == 'default':
self.__defaults.update (section)
self.__sectionlist.append (section_name)
self.__sections.append (section.copy ())
section_name = ''
continue

if not option_name:
option_name = token
token = lex.get_token ()
if token != '=':
raise ParsingError, 'Expected =, got %s' % token

token = lex.get_token ()
if token in ('[', '='):
raise ParsingError, 'expected option value, got %s' % token
option_value = token

if option_value[0] in ('"', "'") and option_value[0] == option_value[-1]:
option_value = option_value[1:-1]

if section.has_key (option_name):
if type (section[option_name]) == ListType:
section[option_name].append (option_value)
else:
section[option_name] = [section[option_name], option_value]
else:
section[option_name] = option_value

option_name = ''

# Done parsing
if section_name:
if section_name in self.__sectionlist:
raise DuplicateSectionError, \
'duplicate section (%s)' % section_name
if section['__name__'] == 'default':
self.__defaults.update (section)
self.__sectionlist.append (section_name)
self.__sections.append (section.copy ())

if not self.__sectionlist:
raise MissingSectionHeaderError, 'no section headers in file'

#######################################
def defaults (self):
'''Return a dictionary containing the passed-in instance-wide defaults.
'''
return self.__defaults.copy ()

#######################################
def has_section (self, section):
'''Indicates whether the named section is present in the configuration.
The default section is not acknowledged.
'''
section = string.lower (section)
if section not in self.sections ():
return 0
return 1

#######################################
def sections (self):
'''Return a list of sections in the configuration file.
'''
s = self.__sectionlist[:]
try:
# Remove 'default' section from returned list
i = s.index ('default')
del s[i]
except ValueError:
# No default section
pass

return s

#######################################
def options (self, section):
'''Return list of options in section.
'''
try:
s = self.__sectionlist.index (string.lower (section))

except ValueError:
raise NoSectionError, 'missing section: "%s"' % section

return self.__sections[s].keys ()

#######################################
def get (self, section, option, raw=0, _vars={}):
'''Get an option value for the provided section. All the "%"
interpolations are expanded in the return values, based on the defaults
passed into the constructor, as well as the options _vars provided,
unless the raw argument is true. __vars contents must be lists.
'''

try:
s = self.__sectionlist.index (string.lower (section))
options = self.__sections[s]
except ValueError:
raise NoSectionError, 'missing section (%s)' % section

expand = self.__defaults.copy ()
expand.update (_vars)

if not options.has_key (option):
if expand.has_key (option):
return expand[option]
raise NoOptionError, 'section [%s] missing option (%s)' \
% (section, option)

rawval = options[option]

if raw:
return rawval

try:
value = []
if type (rawval) != ListType:
rawval = [rawval]
for part in rawval:
try:
part = part % expand
except:
raise
value.append (part)
if len (value) == 1:
return value[0]
return value
except KeyError, txt:
raise NoOptionError, 'section [%s] missing option (%s)' \
% (section, option)
except TypeError, txt:
raise InterpolationError, 'invalid conversion or specification' \
' for option %s (%s (%s))' % (option, rawval, txt)

#######################################
def getint (self, section, option):
'''A convenience method which coerces the option in the specified
section to an integer.
'''
val = self.get (section, option)
try:
return int (val)
except ValueError:
raise InterpolationError, 'option %s not an integer (%s)' \
% (option, val)

#######################################
def getfloat (self, section, option):
'''A convenience method which coerces the option in the specified
section to a floating point number.
'''
val = self.get (section, option)
try:
return float (val)
except ValueError:
raise InterpolationError, 'option %s not a float (%s)' \
% (option, val)

#######################################
def getboolean (self, section, option):
'''A convenience method which coerces the option in the specified
section to a boolean value. Note that the only accepted values for the
option are "0" and "1", any others will raise ValueError.
'''
val = self.getint (section, option)
return val != 0

#######################################
def dump (self):
'''Dump the parsed contents of the configuration file.
'''
sys.stderr.write ('ConfParser dump:\n\n')
sections = self.__sectionlist[:]
sections.sort ()
for section in sections:
sys.stderr.write (' Section [%s]:\n' % section)
options = self.options (section)
options.sort ()
for option in options:
values = self.get (section, option)
if type (values) == ListType:
sys.stderr.write (' %s:\n' % option)
for value in values:
sys.stderr.write (' %s\n' % value)
else:
sys.stderr.write (' %s: %s\n' % (option, values))
sys.stderr.write ('\n')

</pre>

[[Category:Python]]

ConfParser.py - Revision history

PeterHarding at 06:05, 19 July 2009

PeterHarding: New page:
#!/usr/bin/python '''Configuration file parser for files similar to MS-Windows .ini files. Meant as a replacement for the broken ConfigParser module in the Python standard library. ...