Task #7432: Added python Message library

LCS/MessageBus/src/CMakeLists.txt

@@ -21,5 +21,6 @@ endforeach(prog ${messagebus_PROGRAMS})
 python_install(
   __init__.py
   MsgBus.py
+  Message.py
   DESTINATION lofar/messagebus)
 

LCS/MessageBus/src/Message.py

+#!/usr/bin/python
+# Copyright (C) 2012-2015  ASTRON (Netherlands Institute for Radio Astronomy)
+# P.O. Box 2, 7990 AA Dwingeloo, The Netherlands
+#
+# This file is part of the LOFAR software suite.
+# The LOFAR software suite is free software: you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# The LOFAR software suite is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with the LOFAR software suite. If not, see <http://www.gnu.org/licenses/>.
+
+import qpid.messaging
+import xml.dom.minidom as xml
+
+__slots__ = ["Message"]
+
+LOFAR_MSG_TEMPLATE = """
+<message>
+   <header>
+      <system></system>
+      <version></version>
+      <protocol>
+         <name></name>
+         <version></version>
+      </protocol>
+      <source>
+         <name></name>
+         <user></user>
+         <uuid></uuid>
+         <timestamp></timestamp>
+         <summary></summary>
+      </source>
+      <ids>
+         <momid></momid>
+         <sasid></sasid>
+      </ids>
+   </header>
+   <payload>
+   </payload>
+</message>"""
+
+class Message(object):
+    def __init__(self, from_, forUser, summary, protocol, protocolVersion, momid, sasid):
+      self.qpidMsg = qpid.messaging.Message()
+      self.document = xml.parseString(LOFAR_MSG_TEMPLATE)
+
+      for name, element in self._property_list().iteritems():
+        self._add_property(name, element)
+
+      # Set properties provided by constructor
+      self.system          = "LOFAR"
+      self.headerVersion   = "1.0.0"
+      self.protocol        = protocol
+      self.protocolVersion = protocolVersion
+      self.from_           = from_
+      self.forUser         = forUser
+      self.summary         = summary
+      self.uuid            = ""
+      self.timestamp       = ""
+      self.momid           = momid
+      self.sasid           = sasid
+
+    def _add_property(self, name, element):
+      def getter(self):
+        return self._getXMLdata(element)
+      def setter(self, value):
+        self._setXMLdata(element, value)
+
+      setattr(self.__class__, name, property(getter, setter))
+
+    def _property_list(self):
+      """ List of XML elements that are exposed as properties. """
+      return { 
+        "system":          "message.header.system",
+        "headerVersion":   "message.header.version",
+        "protocol":        "message.header.protocol.name",
+        "protocolVersion": "message.header.protocol.version",
+        "from_":           "message.header.source.name",
+        "forUser":         "message.header.source.user",
+        "uuid":            "message.header.source.uuid",
+        "summary":         "message.header.source.summary",
+        "timestamp":       "message.header.source.timestamp",
+        "momid":           "message.header.ids.momid",
+        "sasid":           "message.header.ids.sasid",
+        "payload":         "message.payload",
+        "header":          "message.header",
+      }
+
+    """ API (apart from properties). """
+
+    def setXMLPayload(self, payload):
+      self.qpidMsg.setContent(self.content_template % (payload,))
+
+    setTXTPayload = setXMLPayload
+
+    def __repr__(self):
+      return "Message(%s %s)" % (self.protocol, self.protocolVersion)
+
+    def __str__(self):
+      return ("system         : %s\n" % (self.system,) +
+              "systemversion  : %s\n" % (self.headerVersion,) +
+              "protocol       : %s\n" % (self.protocol,) +
+              "protocolVersion: %s\n" % (self.protocolVersion,) +
+              "summary        : %s\n" % (self.summary,) +
+              "timestamp      : %s\n" % (self.timestamp,) +
+              "source         : %s\n" % (self.from_,) +
+              "user           : %s\n" % (self.forUser,) +
+              "uuid           : %s\n" % (self.uuid,) +
+              "momid          : %s\n" % (self.momid,) +
+              "sasid          : %s\n" % (self.sasid,) +
+              "payload        : %s\n" % (self.payload,)
+             )
+
+    """ XML support functions. See also lofarpipe/support/xmllogging.py. """
+
+    def _get_child(self, node, name):
+      """ Return a specific child node. """
+
+      for child in node.childNodes:
+        if child.nodeName == name and child.nodeType == child.ELEMENT_NODE:
+          return child
+
+      return None
+
+    def _get_data(self, node):
+      """ Return the textual content of a node. """
+
+      data = []
+      for child in node.childNodes:
+        if child.nodeType == child.TEXT_NODE:
+          data.append(child.data)
+
+      return ''.join(data)
+
+    def _set_data(self, node, data):
+      """ Set the textual content of a node. """
+
+      newchild = self.document.createTextNode(data)
+
+      for child in node.childNodes:
+        if child.nodeType == child.TEXT_NODE:
+          node.replaceChild(newchild, child)
+          break;
+      else:
+        node.appendChild(newchild)
+
+    def _getXMLnode(self, name):
+      """ Return a node given by its dot-separated path name.
+          So a.b.c returns the inner node of <a><b><c></c></b></a>. """
+      parts = name.split(".")
+      node = self.document
+
+      for p in parts:
+        node = self._get_child(node,p)
+
+        if node is None:
+          return None
+
+      return node
+
+    def _getXMLdata(self, name):
+      return self._get_data(self._getXMLnode(name))
+
+    def _setXMLdata(self, name, data):
+      return self._set_data(self._getXMLnode(name), data)
+
+if __name__ == "__main__":
+  m = Message("FROM", "FORUSER", "SUMMARY", "PROTOCOL", "1.2.3", "11111", "22222")
+  print str(m)
+