sfatables/xmlrule.py

   1 import sys,os
   2
   3 import libxml2
   4 # allow to run sfa2wsdl if this is missing (for mac)
   5 try:import libxslt
   6 except: print >>sys.stderr, "WARNING, could not import libxslt"
   7
   8 from sfatables.globals import sfatables_config
   9
  10 class XMLRule:
  11     def apply_processor(self, type, doc, output_xpath_filter=None):
  12         processor = self.processors[type]
  13
  14         # XXX TO CLEAN UP
  15         filepath = os.path.join(sfatables_config, 'processors', processor)
  16         # XXX
  17
  18         styledoc = libxml2.parseFile(filepath)
  19         style = libxslt.parseStylesheetDoc(styledoc)
  20         result = style.applyStylesheet(doc, None)
  21         if (output_xpath_filter):
  22             p = result.xpathNewContext()
  23             xpath_result = p.xpathEval(output_xpath_filter)
  24             if (xpath_result == []):
  25                 raise Exception("Could not apply processor %s."%processor)
  26
  27             stylesheet_result = xpath_result
  28             p.xpathFreeContext()
  29         else:
  30             stylesheet_result = result #style.saveResultToString(result)
  31
  32         style.freeStylesheet()
  33         #doc.freeDoc()
  34         #result.freeDoc()
  35
  36         return stylesheet_result
  37
  38     def wrap_up(self, doc):
  39         filepath = os.path.join(sfatables_config, 'processors', self.final_processor)
  40
  41         if not os.path.exists(filepath):
  42             raise Exception('Could not find final rule filter')
  43
  44         styledoc = libxml2.parseFile(filepath)
  45         style = libxslt.parseStylesheetDoc(styledoc)
  46         result = style.applyStylesheet(doc, None)
  47         stylesheet_result = result#style.saveResultToString(result)
  48         style.freeStylesheet()
  49         #doc.freeDoc()
  50         #result.freeDoc()
  51
  52         return stylesheet_result
  53
  54     def match(self, rspec):
  55         match_result = self.apply_processor('match',rspec,"//result/@verdict")
  56         return (match_result[0].content=='True')
  57
  58     def target(self, rspec):
  59         target_result = self.apply_processor('target',rspec,None)
  60         return target_result
  61
  62     def add_rule_context_to_rspec(self, doc):
  63         p = doc.xpathNewContext()
  64         context = p.xpathEval("//*")
  65         if not context or context[0].name not in ['RSpec', 'rspec']:
  66             raise Exception('Request is not an rspec')
  67         else:
  68             # Add the request context
  69             matchNode = libxml2.newNode('match-context')
  70             for match_argument in self.arguments['match']:
  71                 matchNode.addChild(match_argument)
  72
  73             targetNode = libxml2.newNode('target-context')
  74             for target_argument in self.arguments['target']:
  75                 targetNode.addChild(target_argument)
  76
  77             context[0].addChild(matchNode)
  78             context[0].addChild(targetNode)
  79         p.xpathFreeContext()
  80
  81         return doc
  82
  83     def apply_interpreted(self, rspec):
  84         rspec = self.add_rule_context_to_rspec(rspec)
  85         # Interpreted
  86         #
  87         # output =
  88         #    if (match(match_args, rspec)
  89         #       then target(target_args, rspec)
  90         #       else rspec
  91
  92         if (self.match(rspec)):
  93             return (True,self.wrap_up(self.target(rspec)))
  94         else:
  95             return (False,self.wrap_up(rspec))
  96
  97
  98     def apply_compiled(self, rspec):
  99         # Not supported yet
 100         return None
 101
 102     def load_xml_extension (self, type, chain, rule_number):
 103         filename = sfatables_config+"/"+chain+"/"+"sfatables-%d-%s"%(rule_number,type)
 104
 105         self.xmldoc = libxml2.parseFile(filename)
 106         p = self.xmldoc.xpathNewContext()
 107
 108         context = p.xpathEval('//context/@select')
 109         self.context[type] = context[0].content
 110
 111         processor = p.xpathEval('//processor/@filename')
 112
 113         context = p.xpathEval('//attributes/attribute[@terminal="yes"]')
 114         if (context != []):
 115             self.terminal = 1
 116
 117         self.processors[type] = processor[0].content
 118         self.arguments[type] = p.xpathEval('//rule//argument[value!=""]')
 119
 120         p.xpathFreeContext()
 121
 122
 123     def __init__(self, chain=None, rule_number=None):
 124         self.rule_number = None
 125         self.chain = None
 126         self.xmldoc = None
 127         self.terminal = 0
 128         self.final_processor = '__sfatables_rule_wrap_up__.xsl'
 129
 130         self.arguments = {'match':None,'target':None}
 131         self.processors = {'match':None,'target':None}
 132         self.context = {'match':None,'target':None}
 133
 134         if (chain and rule_number):
 135             self.load_xml_extension('match', chain, rule_number)
 136             self.load_xml_extension('target',chain, rule_number)
 137             self.rule_number = rule_number
 138             self.chain = chain
 139         return
 140
 141     def free(self):
 142         self.xmldoc.freeDoc()