cryptonas-branches/pythonrewrite/bin2/CryptoBoxPreferences.py

#!/usr/bin/env python
'''
read and write configuration

This Class is derived mainly from 'gimini' project.
Thanx to Dutoit! <dutoitc(at)hotmail.com>
'''

from ConfigParser import *
import sys, os

### Set the Preferences filename


class Preferences:
    """
    This class handles preferences and stores them into given configfile

    To use it :
      - instanciate a Preferences object : 
        myPP=Preferences()
      - to get a preference :
        mypref=myPP["ma_preference"]
      - to set a preference :
        myPP["ma_preference"]=xxx

    The preferences are automatically loaded on the first instanciation of this
    class and are saved when a value is added or changed automatically, too.
    """
    def __init__(self, filename):
        """
        Constructor

        @author C.Dutoit <dutoitc@hotmail.com>
        """
        self.prefsfilename = filename
        self._config = None
        self.__loadConfig()

    #>--------------------------------------------------------------------------

    def __getitem__(self, name):
        """
        Return the preferences for the given item

        @param String name : Name of the item for which we return a value
        @return String : value of the pref, or None if inexistant
        @since 1.1.2.7
        @author C.Dutoit <dutoitc@hotmail.com>
        """
        if not self._config.has_section("Main"):
	    print "No section: \"[Main]\""
            return None

        try:
            return self._config.get("Main", name)
        except NoOptionError:
	    print "No such option: \"" + name +"\""
            return None

    #>--------------------------------------------------------------------------

    def __setitem__(self, name, value):
        """
        Return the preferences for the given item

        @param String name : Name of the item WITHOUT SPACES
        @param String Value : Value for the given name
        @raises TypeError : if the name contains spaces
        @since 1.1.2.7
        @author C.Dutoit <dutoitc@hotmail.com>
        """
        # Add 'Main' section ?
        if not self._config.has_section("Main"):
            self._config.add_section("Main")

        if " " in list(name):
            raise TypeError, "Name cannot contain a space"

        # Save
        self._config.set("Main", name, str(value))
        self.__saveConfig()

    #>--------------------------------------------------------------------------

    def __saveConfig(self):
        """
        Save datas to config file

        @since 1.1.2.5
        @author C.Dutoit <dutoitc@hotmail.com>
        """
        f=open(self.prefsfilename, "w")
        self._config.write(f)
        f.close()

    #>--------------------------------------------------------------------------

    def __loadConfig(self):
        """
        Load datas from config file

        @since 1.1.2.5
        @author C.Dutoit <dutoitc@hotmail.com>
        """
        # Make sure that the configuration file exist
        try:
            f = open(self.prefsfilename, "r")
            f.close()
        except:
            try:
                f = open(self.prefsfilename, "w")
                f.write("")
                f.close()
            except:
                print "Can't make %s for saving preferences !" % self.prefsfilename
                return


        # Read datas
        self._config=ConfigParser()
        self._config.read(self.prefsfilename)

    #>--------------------------------------------------------------------------

if __name__ == "__main__":
    myPP=Preferences()
    mypref=myPP["ma_preference"]
    myPP["ma_preference"]="xxx"