src/python/osrf/gateway.py

   1 from xml.dom import minidom
   2 from xml.sax import handler, make_parser, saxutils
   3 from json import *
   4 from net_obj import *
   5 import urllib, urllib2, sys, re
   6
   7 defaultHost = None
   8 #paramRegex = re.compile('\%27')
   9
  10 class GatewayRequest:
  11     def __init__(self, service, method, params=[]):
  12         self.service = service
  13         self.method = method
  14         self.params = params
  15
  16     def send(self):
  17         params = self.buildPOSTParams()
  18         request = urllib2.Request(self.buildURL(), data=params)
  19         response = None
  20         try:
  21             response =urllib2.urlopen(request)
  22         except urllib2.HTTPError, e:
  23             # log this?
  24             sys.stderr.write('HTTPError: code=%d : %s' % (e.code, str(e)))
  25             raise e
  26
  27         return self.handleResponse(response)
  28
  29     def buildPOSTParams(self):
  30
  31         params = urllib.urlencode({
  32             'service': self.service,
  33             'method': self.method,
  34             'format': self.getFormat(),
  35             'input_format': self.getInputFormat()
  36         })
  37
  38         for p in self.params:
  39             params += '&param=%s' % urllib.quote(self.encodeParam(p), "'/")
  40         return params
  41
  42     def setDefaultHost(host):
  43         global defaultHost
  44         defaultHost = host
  45     setDefaultHost = staticmethod(setDefaultHost)
  46
  47     def buildURL(self):
  48         return 'http://%s/gateway' % defaultHost
  49
  50
  51 class XMLGatewayRequest(GatewayRequest):
  52
  53     def __init__(self, service, method, *params):
  54         GatewayRequest.__init__(self, service, method, list(params))
  55
  56     def getFormat(self):
  57         return 'xml'
  58
  59     def getInputFormat(self):
  60         return self.getFormat()
  61
  62     def handleResponse(self, response):
  63         handler = XMLGatewayParser()
  64         parser = make_parser()
  65         parser.setContentHandler(handler)
  66         parser.parse(response)
  67         return handler.getResult()
  68
  69     def encodeParam(self, param):
  70         return osrfObjectToXML(param);
  71
  72 class XMLGatewayParser(handler.ContentHandler):
  73
  74     def __init__(self):
  75         self.result = None
  76         self.objStack = []
  77         self.keyStack = []
  78         self.posStack = [] # for tracking array-based hinted object indices
  79
  80     def getResult(self):
  81         return self.result
  82
  83     def __getAttr(self, attrs, name):
  84         for (k, v) in attrs.items():
  85             if k == name:
  86                 return v
  87         return None
  88
  89     def startElement(self, name, attrs):
  90
  91         # XXX add support for serializable objects!
  92
  93         if name == 'null':
  94             self.appendChild(None)
  95             return
  96
  97         if name == 'element': # this is an object item wrapper
  98             self.keyStack.append(self.__getAttr(attrs, 'key'))
  99             return
 100
 101         hint = self.__getAttr(attrs, 'class_hint')
 102         if hint:
 103             obj = osrfNewObjectFromHint(hint)
 104             self.appendChild(obj)
 105             self.objStack.append(obj)
 106             if name == 'array':
 107                 self.posStack.append(0)
 108             return
 109
 110         if name == 'array':
 111             obj = []
 112             self.appendChild(obj)
 113             self.objStack.append(obj)
 114             return
 115
 116         if name == 'object':
 117             obj = {}
 118             self.appendChild(obj)
 119             self.objStack.append(obj)
 120             return
 121
 122         if name == 'boolean':
 123             self.appendChild((self.__getAttr(attrs, 'value') == 'true'))
 124             return
 125
 126
 127     def appendChild(self, child):
 128
 129         if self.result == None:
 130             self.result = child
 131
 132         if not self.objStack: return;
 133
 134         parent = self.objStack[len(self.objStack)-1]
 135
 136         if isinstance(parent, list):
 137             parent.append(child)
 138         else:
 139             if isinstance(parent, dict):
 140                 parent[self.keyStack.pop()] = child
 141             else:
 142                 if isinstance(parent, osrfNetworkObject):
 143                     key = None
 144                     if parent.getRegistry().wireProtocol == 'array':
 145                         keys = parent.getRegistry().keys
 146                         i = self.posStack.pop()
 147                         key = keys[i]
 148                         if i+1 < len(keys):
 149                             self.posStack.append(i+1)
 150                     else:
 151                         key = self.keyStack.pop()
 152
 153                     parent.setField(key, child)
 154
 155     def endElement(self, name):
 156         if name == 'array' or name == 'object':
 157             self.objStack.pop()
 158
 159     def characters(self, chars):
 160         self.appendChild(urllib.unquote_plus(chars))
 161
 162
 163
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 165