src/python/osrf/utils.py

   1 # -----------------------------------------------------------------------
   2 # Copyright (C) 2007  Georgia Public Library Service
   3 # Bill Erickson <billserickson@gmail.com>
   4 #
   5 # This program is free software; you can redistribute it and/or
   6 # modify it under the terms of the GNU General Public License
   7 # as published by the Free Software Foundation; either version 2
   8 # of the License, or (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 # -----------------------------------------------------------------------
  15
  16 import libxml2, re
  17
  18 def osrfXMLFileToObject(filename):
  19         """Turns the contents of an XML file into a Python object"""
  20         doc     = libxml2.parseFile(filename)
  21         xmlNode = doc.children.children
  22         return osrfXMLNodeToObject(xmlNode)
  23
  24 def osrfXMLStringToObject(string):
  25         """Turns an XML string into a Python object"""
  26         doc     = libxml2.parseString(string)
  27         xmlNode = doc.children.children
  28         return osrfXMLNodeToObject(xmlNode)
  29
  30 def osrfXMLNodeToObject(xmlNode):
  31         """Turns an XML node into a Python object"""
  32         obj = {}
  33
  34         while xmlNode:
  35                 if xmlNode.type == 'element':
  36                         nodeChild = xmlNode.children
  37                         done = False
  38                         nodeName = xmlNode.name
  39
  40                         while nodeChild:
  41                                 if nodeChild.type == 'element':
  42
  43                                         # If a node has element children, create a new sub-object
  44                                         # for this node, attach an array for each type of child
  45                                         # and recursively collect the children data into the array(s)
  46
  47                                         if not obj.has_key(nodeName):
  48                                                 obj[nodeName] = {}
  49
  50                                         sub_obj = osrfXMLNodeToObject(nodeChild);
  51
  52                                         if not obj[nodeName].has_key(nodeChild.name):
  53                                                 # we've encountered 1 sub-node with nodeChild's name
  54                                                 obj[nodeName][nodeChild.name] = sub_obj[nodeChild.name]
  55
  56                                         else:
  57                                                 if isinstance(obj[nodeName][nodeChild.name], list):
  58                                                         # we already have multiple sub-nodes with nodeChild's name
  59                                                         obj[nodeName][nodeChild.name].append(sub_obj[nodeChild.name])
  60
  61                                                 else:
  62                                                         # we already have 1 sub-node with nodeChild's name, make
  63                                                         # it a list and append the current node
  64                                                         val = obj[nodeName][nodeChild.name]
  65                                                         obj[nodeName][nodeChild.name] = [ val, sub_obj[nodeChild.name] ]
  66
  67                                         done = True
  68
  69                                 nodeChild = nodeChild.next
  70
  71                         if not done:
  72                                 # If the node has no children, clean up the text content
  73                                 # and use that as the data
  74                                 data = re.compile('^\s*').sub('', xmlNode.content)
  75                                 data = re.compile('\s*$').sub('', data)
  76
  77                                 obj[nodeName] = data
  78
  79                 xmlNode = xmlNode.next
  80
  81         return obj
  82
  83
  84 def osrfObjectFindPath(obj, path, idx=None):
  85         """Searches an object along the given path for a value to return.
  86
  87         Path separaters can be '/' or '.', '/' is tried first."""
  88
  89         parts = []
  90
  91         if re.compile('/').search(path):
  92                 parts = path.split('/')
  93         else:
  94                 parts = path.split('.')
  95
  96         for part in parts:
  97                 try:
  98                         o = obj[part]
  99                 except Exception:
 100                         return None
 101                 if isinstance(o,str):
 102                         return o
 103                 if isinstance(o,list):
 104                         if( idx != None ):
 105                                 return o[idx]
 106                         return o
 107                 if isinstance(o,dict):
 108                         obj = o
 109                 else:
 110                         return o
 111
 112         return obj
 113
 114
 115
 116