laditools/config.py

   1 #!/usr/bin/python
   2 # LADITools - Linux Audio Desktop Integration Tools
   3 # Copyright (C) 2011-2012 Alessio Treglia <quadrispro@ubuntu.com>
   4 # Copyright (C) 2007-2010, Marc-Olivier Barre <marco@marcochapeau.org>
   5 # Copyright (C) 2007-2009, Nedko Arnaudov <nedko@arnaudov.name>
   6 #
   7 # This program is free software: you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation, either version 3 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19
  20 from os import environ, sep, mkdir, path
  21 from os.path import exists
  22 from xdg import BaseDirectory as basedir
  23 import sys
  24
  25 if sys.version_info.major == 3:
  26     from configparser import SafeConfigParser, MissingSectionHeaderError
  27 elif sys.version_info.major == 2:
  28     from ConfigParser import SafeConfigParser, MissingSectionHeaderError
  29 else:
  30     raise Exception("Unsupported Python's interpreter version.")
  31
  32 try:
  33     import yaml
  34 except:
  35     yaml = None
  36
  37 class MalformedConfigError(Exception):
  38     def __init__(self):
  39         Exception.__init__(self, """Malformed configuration file, \
  40 delete the file '%s' and let me create a new one.""" % config_filename)
  41
  42 # Note to users of the config class. Only applications should create an instance
  43 # of the config object. The ladimenu is *NOT* an application...
  44 class LadiConfiguration(SafeConfigParser):
  45     """Convenient class for parsing and updating configuration files.
  46
  47     It is recommended to avoid abuses of these objects, only applications
  48     should create instances of this class.
  49     """
  50
  51     def _migrate_configuration(self):
  52         """Migrate configuration from old YAML coding style to the new one."""
  53         try:
  54             with open (self.config_filename, 'r') as config_file:
  55                 appdict = yaml.load (config_file)
  56         except:
  57             sys.stderr.write("Config file doesn't exist, creating a new one...\n")
  58             sys.stderr.flush()
  59             return 1
  60
  61         for section in appdict:
  62             if not section in self.sections():
  63                 self.add_section(section)
  64             for opt in appdict[section]:
  65                 if not isinstance(opt, dict):
  66                     self.set(section, opt, str(appdict[section][opt]))
  67                 else:
  68                     for k in opt:
  69                         self.set(section, k, opt[k])
  70
  71         return 0
  72
  73     def __init__ (self, app_name, defaults = {}, filename = None):
  74
  75         SafeConfigParser.__init__(self)
  76
  77         # First setup default values for apps specified
  78         # by the call to the contructor
  79         self.set_config_section(app_name, defaults)
  80
  81         self.config_dir = config_dir = path.join(basedir.xdg_config_home, 'laditools')
  82         if not filename:
  83             filename = app_name + '.conf'
  84         self.config_filename = config_filename = path.join(config_dir, filename)
  85         if not exists (config_dir):
  86             mkdir (config_dir, 0o755)
  87
  88         try:
  89             self.read(config_filename)
  90         except MissingSectionHeaderError:
  91             if yaml:
  92                 if self._migrate_configuration() == 0:
  93                     self.save()
  94                 else: # new empty file
  95                     pass
  96             # go on otherwise
  97         except:
  98             raise MalformedConfigError()
  99
 100     def get_config_section (self, app_name):
 101         """Returns the section named <app_name> from the global configuration.
 102
 103         If the section doesn't exist, returns an empty dictionary."""
 104         appdict = {}
 105         if self.has_section(app_name):
 106             for opt in self.options(app_name):
 107                 appdict[opt] = self.get(app_name, opt)
 108         return appdict
 109
 110     # Saves the section named <app_name> into the global config
 111     def set_config_section (self, app_name, param_dict):
 112         """Save the section named <app_name> into the global configuration."""
 113         if not self.has_section(app_name):
 114             self.add_section(app_name)
 115         for key in param_dict:
 116             value = param_dict[key]
 117             self.set(app_name, key, str(value))
 118
 119     # This writes the config file to the disk
 120     def save (self):
 121         """Write configuration to file."""
 122         config_file = open (self.config_filename, 'w')
 123         self.write(config_file)
 124         config_file.close ()