config.py

   1 from __future__ import division
   2 from xml.sax    import ContentHandler
   3
   4
   5
   6 class handler (ContentHandler):
   7
   8   def __init__ (self, data):
   9     ContentHandler.__init__ (self)
  10     self.data  = data
  11     self.trace = []
  12
  13   def startElement (self, name, attrs):
  14     if not self.trace and name != 'config':
  15       raise SAXParseException ('<%s> unexpected' % name)
  16
  17     self.trace.append (name)
  18
  19   def endElement (self, name):
  20     self.trace.pop ()
  21
  22   def characters (self, content):
  23     content = content.strip ()
  24
  25     if content:
  26       self.data['.'.join (self.trace[1:])] = content
  27
  28
  29
  30 class config (dict):
  31
  32   def __init__ (self, path = 'data/config.xml', defaults = {}):
  33     dict.__init__ (self)
  34     self.path, self.defaults = path, defaults
  35
  36     try:
  37       from xml.sax import parse
  38       parse (path, handler (self))
  39     except IOError:
  40       pass
  41
  42   def __getitem__ (self, key):
  43     if dict.__contains__ (self, key):
  44       return dict.__getitem__ (self, key)
  45     else:
  46       return self.defaults[key]
  47
  48   def save (self, path = None):
  49     if not path:
  50       path = self.path
  51
  52     if not path:
  53       path = 'data/config.xml'
  54
  55     file = open (path, 'w')
  56
  57     try:
  58       file.write ('<config>\n')
  59
  60       keys = {}
  61
  62       for k in self.keys ():
  63         keys[k] = None
  64
  65       for k in self.defaults.keys ():
  66         keys[k] = None
  67
  68       keys = keys.keys ()
  69       keys.sort ()
  70       trace = []
  71
  72       for k in keys:
  73         value = self[k]
  74         path = k.split ('.')
  75
  76         while trace != path[:len (trace)]:
  77           file.write (len (trace) * '  ' + '</%s>\n' % trace.pop ())
  78
  79         path, _, name = k.rpartition ('.')
  80         path = path.split ('.')
  81
  82         while trace != path:
  83           trace.append (path[len (trace)])
  84           file.write (len (trace) * '  ' + '<%s>\n' % trace[-1])
  85
  86         file.write (len (trace) * '  ' + '  <%s>%s</%s>\n' %
  87                     (name, value, name))
  88
  89       while trace:
  90         file.write (len (trace) * '  ' + '</%s>\n' % trace.pop ())
  91
  92       file.write ('</config>\n')
  93     finally:
  94       file.close ()