jens@11: # encoding: utf-8
jens@11: """
jens@11: BLIP.py
jens@11: 
jens@11: Created by Jens Alfke on 2008-06-03.
jens@13: Copyright notice and BSD license at end of file.
jens@11: """
jens@11: 
jens@11: import asynchat
jens@11: import asyncore
jens@11: from cStringIO import StringIO
jens@11: import logging
jens@11: import socket
jens@11: import struct
jens@11: import sys
jens@11: import traceback
jens@11: import zlib
jens@11: 
jens@11: 
jens@13: # Connection status enumeration:
jens@13: kDisconnected = -1
jens@13: kClosed  = 0
jens@13: kOpening = 1
jens@13: kOpen    = 2
jens@13: kClosing = 3
jens@13: 
jens@13: 
jens@12: # INTERNAL CONSTANTS -- NO TOUCHIES!
jens@12: 
morrowa@51: kFrameMagicNumber   = 0x9B34F206
jens@11: kFrameHeaderFormat  = '!LLHH'
jens@11: kFrameHeaderSize    = 12
jens@11: 
jens@11: kMsgFlag_TypeMask   = 0x000F
jens@11: kMsgFlag_Compressed = 0x0010
jens@11: kMsgFlag_Urgent     = 0x0020
jens@11: kMsgFlag_NoReply    = 0x0040
jens@11: kMsgFlag_MoreComing = 0x0080
morrowa@51: kMsgFlag_Meta       = 0x0100
jens@11: 
jens@11: kMsgType_Request    = 0
jens@11: kMsgType_Response   = 1
jens@11: kMsgType_Error      = 2
jens@11: 
morrowa@51: kMsgProfile_Hi      = "Hi"
morrowa@51: kMsgProfile_Bye     = "Bye"
morrowa@51: 
morrowa@56: # Logging Setup
morrowa@56: class NullLoggingHandler(logging.Handler):
morrowa@56:     def emit(self, record):
morrowa@56:         pass
jens@11: 
jens@11: log = logging.getLogger('BLIP')
morrowa@56: # This line prevents the "No handlers found" warning if the calling code does not use logging.
morrowa@56: log.addHandler(NullLoggingHandler())
jens@11: log.propagate = True
jens@11: 
jens@12: 
jens@11: class MessageException(Exception):
jens@11:     pass
jens@11: 
jens@11: class ConnectionException(Exception):
jens@11:     pass
jens@11: 
jens@11: 
jens@13: ### LISTENER AND CONNECTION CLASSES:
jens@13: 
jens@13: 
jens@11: class Listener (asyncore.dispatcher):
jens@12:     "BLIP listener/server class"
jens@12:     
jens@13:     def __init__(self, port, sslKeyFile=None, sslCertFile=None):
jens@12:         "Create a listener on a port"
jens@11:         asyncore.dispatcher.__init__(self)
jens@12:         self.onConnected = self.onRequest = None
jens@11:         self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
jens@11:         self.bind( ('',port) )
jens@11:         self.listen(5)
jens@13:         self.sslKeyFile=sslKeyFile
jens@13:         self.sslCertFile=sslCertFile
jens@11:         log.info("Listening on port %u", port)
jens@11:     
jens@11:     def handle_accept( self ):
jens@13:         socket,address = self.accept()
jens@13:         if self.sslKeyFile:
jens@13:             socket.ssl(socket,self.sslKeyFile,self.sslCertFile)
jens@13:         conn = Connection(address, sock=socket, listener=self)
jens@11:         conn.onRequest = self.onRequest
jens@11:         if self.onConnected:
jens@11:             self.onConnected(conn)
jens@11: 
jens@13:     def handle_error(self):
jens@13:         (typ,val,trace) = sys.exc_info()
jens@13:         log.error("Listener caught: %s %s\n%s", typ,val,traceback.format_exc())
jens@13:         self.close()
jens@13:     
jens@13: 
jens@11: 
jens@11: class Connection (asynchat.async_chat):
jens@13:     def __init__( self, address, sock=None, listener=None, ssl=None ):
jens@12:         "Opens a connection with the given address. If a connection/socket object is provided it'll use that,"
jens@12:         "otherwise it'll open a new outgoing socket."
jens@13:         if sock:
jens@13:             asynchat.async_chat.__init__(self,sock)
jens@11:             log.info("Accepted connection from %s",address)
jens@13:             self.status = kOpen
jens@11:         else:
jens@13:             asynchat.async_chat.__init__(self)
jens@11:             log.info("Opening connection to %s",address)
jens@11:             self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
jens@13:             self.status = kOpening
jens@13:             if ssl:
jens@13:                 ssl(self.socket)
jens@11:             self.connect(address)
jens@13:         self.address = address
jens@13:         self.listener = listener
morrowa@51:         self.onRequest = self.onCloseRequest = self.onCloseRefused = None
jens@11:         self.pendingRequests = {}
jens@11:         self.pendingResponses = {}
jens@11:         self.outBox = []
jens@11:         self.inMessage = None
jens@13:         self.inNumRequests = self.outNumRequests = 0
jens@14:         self.sending = False
jens@11:         self._endOfFrame()
morrowa@51:         self._closeWhenPossible = False
jens@11:     
jens@13:     def handle_connect(self):
jens@13:         log.info("Connection open!")
jens@13:         self.status = kOpen
jens@13:     
jens@13:     def handle_error(self):
jens@13:         (typ,val,trace) = sys.exc_info()
jens@13:         log.error("Connection caught: %s %s\n%s", typ,val,traceback.format_exc())
jens@13:         self.discard_buffers()
jens@13:         self.status = kDisconnected
jens@11:         self.close()
jens@11:     
jens@11:     
jens@11:     ### SENDING:
jens@11:     
jens@13:     @property
morrowa@51:     def isOpen(self):
jens@13:         return self.status==kOpening or self.status==kOpen
jens@13:     
morrowa@51:     @property
morrowa@51:     def canSend(self):
morrowa@51:         return self.isOpen and not self._closeWhenPossible
morrowa@51:     
jens@13:     def _sendMessage(self, msg):
morrowa@51:         if self.isOpen:
jens@13:             self._outQueueMessage(msg,True)
jens@14:             if not self.sending:
jens@14:                 log.debug("Waking up the output stream")
jens@14:                 self.sending = True
jens@14:                 self.push_with_producer(self)
jens@13:             return True
jens@13:         else:
jens@13:             return False
jens@13:     
jens@13:     def _sendRequest(self, req):
jens@13:         if self.canSend:
jens@13:             requestNo = req.requestNo = self.outNumRequests = self.outNumRequests + 1
jens@13:             response = req.response
jens@13:             if response:
jens@13:                 response.requestNo = requestNo
jens@13:                 self.pendingResponses[requestNo] = response
jens@13:                 log.debug("pendingResponses[%i] := %s",requestNo,response)
jens@13:             return self._sendMessage(req)
jens@13:         else:
morrowa@54:             log.warning("%s: Attempt to send a request after the connection has started closing: %s" % (self, req))
jens@13:             return False
jens@13:     
jens@11:     def _outQueueMessage(self, msg,isNew=True):
jens@12:         n = len(self.outBox)
jens@11:         index = n
jens@11:         if msg.urgent and n>1:
jens@11:             while index > 0:
jens@12:                 otherMsg = self.outBox[index-1]
jens@11:                 if otherMsg.urgent:
jens@11:                     if index<n:
jens@11:                         index += 1
jens@11:                     break
jens@14:                 elif isNew and otherMsg.bytesSent==0:
jens@11:                     break
jens@11:                 index -= 1
jens@11:             else:
jens@11:                 index = 1
jens@12:         
jens@11:         self.outBox.insert(index,msg)
jens@11:         if isNew:
jens@13:             log.info("Queuing %s at index %i",msg,index)
jens@12:         else:
jens@12:             log.debug("Re-queueing outgoing message at index %i of %i",index,len(self.outBox))
jens@11:     
jens@14:     def more(self):
jens@14:         n = len(self.outBox)
jens@14:         if n > 0:
jens@14:             msg = self.outBox.pop(0)
jens@14:             frameSize = 4096
jens@14:             if msg.urgent or n==1 or not self.outBox[0].urgent:
jens@14:                 frameSize *= 4
jens@14:             data = msg._sendNextFrame(frameSize)
jens@14:             if msg._moreComing:
jens@14:                 self._outQueueMessage(msg,isNew=False)
jens@14:             else:
jens@14:                 log.info("Finished sending %s",msg)
jens@14:             return data
jens@14:         else:
jens@14:             log.debug("Nothing more to send")
jens@14:             self.sending = False
morrowa@51:             self._closeIfReady()
jens@14:             return None
jens@11:     
jens@11:     ### RECEIVING:
jens@11:     
jens@11:     def collect_incoming_data(self, data):
jens@11:         if self.expectingHeader:
jens@11:             if self.inHeader==None:
jens@11:                 self.inHeader = data
jens@11:             else:
jens@11:                 self.inHeader += data
jens@13:         elif self.inMessage:
jens@11:             self.inMessage._receivedData(data)
jens@12:     
jens@11:     def found_terminator(self):
jens@11:         if self.expectingHeader:
jens@11:             # Got a header:
jens@11:             (magic, requestNo, flags, frameLen) = struct.unpack(kFrameHeaderFormat,self.inHeader)
jens@11:             self.inHeader = None
jens@13:             if magic!=kFrameMagicNumber: raise ConnectionException, "Incorrect frame magic number %x" %magic
jens@13:             if frameLen < kFrameHeaderSize: raise ConnectionException,"Invalid frame length %u" %frameLen
jens@11:             frameLen -= kFrameHeaderSize
jens@11:             log.debug("Incoming frame: type=%i, number=%i, flags=%x, length=%i",
jens@11:                         (flags&kMsgFlag_TypeMask),requestNo,flags,frameLen)
jens@11:             self.inMessage = self._inMessageForFrame(requestNo,flags)
jens@11:             
jens@11:             if frameLen > 0:
jens@11:                 self.expectingHeader = False
jens@11:                 self.set_terminator(frameLen)
jens@11:             else:
jens@11:                 self._endOfFrame()
jens@12:         
jens@11:         else:
jens@11:             # Got the frame's payload:
jens@11:             self._endOfFrame()
jens@11:     
jens@11:     def _inMessageForFrame(self, requestNo,flags):
jens@11:         message = None
jens@11:         msgType = flags & kMsgFlag_TypeMask
jens@11:         if msgType==kMsgType_Request:
jens@11:             message = self.pendingRequests.get(requestNo)
jens@11:             if message==None and requestNo == self.inNumRequests+1:
jens@11:                 message = IncomingRequest(self,requestNo,flags)
jens@12:                 assert message!=None
jens@11:                 self.pendingRequests[requestNo] = message
jens@11:                 self.inNumRequests += 1
jens@11:         elif msgType==kMsgType_Response or msgType==kMsgType_Error:
jens@11:             message = self.pendingResponses.get(requestNo)
morrowa@51:             message._updateFlags(flags)
jens@12:         
jens@12:         if message != None:
jens@11:             message._beginFrame(flags)
jens@11:         else:
jens@11:             log.warning("Ignoring unexpected frame with type %u, request #%u", msgType,requestNo)
jens@11:         return message
jens@11:     
jens@11:     def _endOfFrame(self):
jens@11:         msg = self.inMessage
jens@11:         self.inMessage = None
jens@11:         self.expectingHeader = True
jens@11:         self.inHeader = None
jens@11:         self.set_terminator(kFrameHeaderSize) # wait for binary header
jens@11:         if msg:
jens@11:             log.debug("End of frame of %s",msg)
jens@13:             if not msg._moreComing:
jens@11:                 self._receivedMessage(msg)
jens@12:     
jens@11:     def _receivedMessage(self, msg):
jens@11:         log.info("Received: %s",msg)
jens@11:         # Remove from pending:
jens@11:         if msg.isResponse:
jens@13:             del self.pendingResponses[msg.requestNo]
jens@11:         else:
jens@11:             del self.pendingRequests[msg.requestNo]
jens@11:         # Decode:
jens@11:         try:
jens@11:             msg._finished()
jens@12:             if not msg.isResponse:
morrowa@51:                 if msg._meta:
morrowa@51:                     self._dispatchMetaRequest(msg)
morrowa@51:                 else:
morrowa@51:                     self.onRequest(msg)
jens@11:         except Exception, x:
jens@12:             log.error("Exception handling incoming message: %s", traceback.format_exc())
jens@11:             #FIX: Send an error reply
morrowa@51:         # Check to see if we're done and ready to close:
morrowa@51:         self._closeIfReady()
morrowa@51:     
morrowa@51:     def _dispatchMetaRequest(self, request):
morrowa@51:         """Handles dispatching internal meta requests."""
morrowa@51:         if request['Profile'] == kMsgProfile_Bye:
morrowa@54:             self._handleCloseRequest(request)
morrowa@51:         else:
morrowa@51:             response = request.response
morrowa@51:             response.isError = True
morrowa@51:             response['Error-Domain'] = "BLIP"
morrowa@51:             response['Error-Code'] = 404
morrowa@51:             response.body = "Unknown meta profile"
morrowa@51:             response.send()
morrowa@51:     
morrowa@51:     ### CLOSING:
morrowa@51:     
morrowa@54:     def _handleCloseRequest(self, request):
morrowa@54:         """Handles requests from a peer to close."""
morrowa@54:         shouldClose = True
morrowa@54:         if self.onCloseRequest:
morrowa@54:             shouldClose = self.onCloseRequest()
morrowa@54:         if not shouldClose:
morrowa@54:             log.debug("Sending resfusal to close...")
morrowa@54:             response = request.response
morrowa@54:             response.isError = True
morrowa@54:             response['Error-Domain'] = "BLIP"
morrowa@54:             response['Error-Code'] = 403
morrowa@54:             response.body = "Close request denied"
morrowa@54:             response.send()
morrowa@54:         else:
morrowa@54:             log.debug("Sending permission to close...")
morrowa@54:             response = request.response
morrowa@54:             response.send()
morrowa@54:     
morrowa@51:     def close(self):
morrowa@51:         """Publicly callable close method. Sends close request to peer."""
morrowa@51:         if self.status != kOpen:
morrowa@51:             return False
morrowa@51:         log.info("Sending close request...")
morrowa@51:         req = OutgoingRequest(self, None, {'Profile': kMsgProfile_Bye})
morrowa@51:         req._meta = True
morrowa@51:         req.response.onComplete = self._handleCloseResponse
morrowa@51:         if not req.send():
morrowa@51:             log.error("Error sending close request.")
morrowa@51:             return False
morrowa@51:         else:
morrowa@51:             self.status = kClosing
morrowa@51:         return True
morrowa@51:     
morrowa@51:     def _handleCloseResponse(self, response):
morrowa@51:         """Called when we receive a response to a close request."""
morrowa@51:         log.info("Received close response.")
morrowa@51:         if response.isError:
morrowa@51:             # remote refused to close
morrowa@51:             if self.onCloseRefused:
morrowa@51:                 self.onCloseRefused(response)
morrowa@51:             self.status = kOpen
morrowa@51:         else:
morrowa@51:             # now wait until everything has finished sending, then actually close
morrowa@51:             log.info("No refusal, actually closing...")
morrowa@51:             self._closeWhenPossible = True
morrowa@51:     
morrowa@51:     def _closeIfReady(self):
morrowa@51:         """Checks if all transmissions are complete and then closes the actual socket."""
morrowa@51:         if self._closeWhenPossible and len(self.outBox) == 0 and len(self.pendingRequests) == 0 and len(self.pendingResponses) == 0:
morrowa@51:             # self._closeWhenPossible = False
morrowa@51:             log.debug("_closeIfReady closing.")
morrowa@51:             asynchat.async_chat.close(self)
morrowa@51:     
morrowa@51:     def handle_close(self):
morrowa@51:         """Called when the socket actually closes."""
morrowa@51:         log.info("Connection closed!")
morrowa@51:         self.pendingRequests = self.pendingResponses = None
morrowa@51:         self.outBox = None
morrowa@51:         if self.status == kClosing:
morrowa@51:             self.status = kClosed
morrowa@51:         else:
morrowa@51:             self.status = kDisconnected
morrowa@53:         asyncore.dispatcher.close(self)
jens@11: 
jens@12: 
jens@13: ### MESSAGE CLASSES:
jens@11: 
jens@11: 
jens@11: class Message (object):
jens@12:     "Abstract superclass of all request/response objects"
jens@12:     
jens@13:     def __init__(self, connection, body=None, properties=None):
jens@11:         self.connection = connection
jens@13:         self.body = body
jens@11:         self.properties = properties or {}
jens@13:         self.requestNo = None
jens@11:     
jens@11:     @property
jens@11:     def flags(self):
jens@12:         if self.isResponse:
morrowa@51:             if self.isError:
morrowa@51:                 flags = kMsgType_Error
morrowa@51:             else:
morrowa@51:                 flags = kMsgType_Response
jens@12:         else:
jens@12:             flags = kMsgType_Request
jens@11:         if self.urgent:     flags |= kMsgFlag_Urgent
jens@11:         if self.compressed: flags |= kMsgFlag_Compressed
jens@11:         if self.noReply:    flags |= kMsgFlag_NoReply
jens@13:         if self._moreComing:flags |= kMsgFlag_MoreComing
morrowa@51:         if self._meta:      flags |= kMsgFlag_Meta
jens@11:         return flags
jens@11:     
jens@11:     def __str__(self):
jens@13:         s = "%s[" %(type(self).__name__)
jens@13:         if self.requestNo != None:
jens@13:             s += "#%i" %self.requestNo
jens@11:         if self.urgent:     s += " URG"
jens@11:         if self.compressed: s += " CMP"
jens@11:         if self.noReply:    s += " NOR"
jens@13:         if self._moreComing:s += " MOR"
morrowa@51:         if self._meta:      s += " MET"
jens@11:         if self.body:       s += " %i bytes" %len(self.body)
jens@11:         return s+"]"
jens@11:     
jens@11:     def __repr__(self):
jens@11:         s = str(self)
jens@11:         if len(self.properties): s += repr(self.properties)
jens@11:         return s
jens@12:     
jens@13:     @property
jens@11:     def isResponse(self):
jens@12:         "Is this message a response?"
jens@11:         return False
jens@12:     
jens@13:     @property
jens@12:     def contentType(self):
jens@12:         return self.properties.get('Content-Type')
jens@12:     
jens@12:     def __getitem__(self, key):     return self.properties.get(key)
jens@12:     def __contains__(self, key):    return key in self.properties
jens@12:     def __len__(self):              return len(self.properties)
jens@12:     def __nonzero__(self):          return True
jens@12:     def __iter__(self):             return self.properties.__iter__()
jens@11: 
jens@11: 
jens@11: class IncomingMessage (Message):
jens@12:     "Abstract superclass of incoming messages."
jens@12:     
jens@11:     def __init__(self, connection, requestNo, flags):
jens@11:         super(IncomingMessage,self).__init__(connection)
jens@11:         self.requestNo  = requestNo
morrowa@51:         self._updateFlags(flags)
morrowa@51:         self.frames     = []
morrowa@51:     
morrowa@51:     def _updateFlags(self, flags):
jens@12:         self.urgent     = (flags & kMsgFlag_Urgent) != 0
jens@11:         self.compressed = (flags & kMsgFlag_Compressed) != 0
jens@11:         self.noReply    = (flags & kMsgFlag_NoReply) != 0
jens@13:         self._moreComing= (flags & kMsgFlag_MoreComing) != 0
morrowa@51:         self._meta      = (flags & kMsgFlag_Meta) != 0
morrowa@51:         self.isError    = (flags & kMsgType_Error) != 0
jens@11:     
jens@11:     def _beginFrame(self, flags):
jens@13:         """Received a frame header."""
jens@13:         self._moreComing = (flags & kMsgFlag_MoreComing)!=0
jens@12:     
jens@11:     def _receivedData(self, data):
jens@13:         """Received data from a frame."""
jens@11:         self.frames.append(data)
jens@11:     
jens@11:     def _finished(self):
jens@13:         """The entire message has been received; now decode it."""
jens@11:         encoded = "".join(self.frames)
jens@11:         self.frames = None
jens@11:         
jens@11:         # Decode the properties:
jens@11:         if len(encoded) < 2: raise MessageException, "missing properties length"
jens@11:         propSize = 2 + struct.unpack('!H',encoded[0:2])[0]
jens@11:         if propSize>len(encoded): raise MessageException, "properties too long to fit"
jens@11:         if propSize>2 and encoded[propSize-1] != '\000': raise MessageException, "properties are not nul-terminated"
jens@11:         
morrowa@51:         if propSize > 2:
morrowa@51:             proplist = encoded[2:propSize-1].split('\000')
morrowa@51:         
morrowa@51:             if len(proplist) & 1: raise MessageException, "odd number of property strings"
morrowa@51:             for i in xrange(0,len(proplist),2):
morrowa@51:                 def expand(str):
morrowa@51:                     if len(str)==1:
morrowa@51:                         str = IncomingMessage.__expandDict.get(str,str)
morrowa@51:                     return str
morrowa@51:                 self.properties[ expand(proplist[i])] = expand(proplist[i+1])
morrowa@51:         
jens@11:         encoded = encoded[propSize:]
jens@11:         # Decode the body:
jens@11:         if self.compressed and len(encoded)>0:
jens@11:             try:
jens@11:                 encoded = zlib.decompress(encoded,31)   # window size of 31 needed for gzip format
jens@11:             except zlib.error:
jens@11:                 raise MessageException, sys.exc_info()[1]
jens@11:         self.body = encoded
jens@11:     
jens@11:     __expandDict= {'\x01' : "Content-Type",
jens@11:                    '\x02' : "Profile",
jens@11:                    '\x03' : "application/octet-stream",
jens@11:                    '\x04' : "text/plain; charset=UTF-8",
jens@11:                    '\x05' : "text/xml",
jens@11:                    '\x06' : "text/yaml",
jens@11:                    '\x07' : "Channel",
jens@11:                    '\x08' : "Error-Code",
jens@11:                    '\x09' : "Error-Domain"}
jens@12: 
jens@11: 
jens@11: class OutgoingMessage (Message):
jens@12:     "Abstract superclass of outgoing requests/responses."
jens@12:     
jens@13:     def __init__(self, connection, body=None, properties=None):
jens@13:         Message.__init__(self,connection,body,properties)
morrowa@51:         self.urgent = self.compressed = self.noReply = self._meta = self.isError = False
jens@13:         self._moreComing = True
jens@12:     
jens@12:     def __setitem__(self, key,val):
jens@12:         self.properties[key] = val
jens@12:     def __delitem__(self, key):
jens@12:         del self.properties[key]
jens@11:     
jens@13:     @property
jens@13:     def sent(self):
jens@16:         return hasattr(self,'encoded')
jens@13:     
jens@13:     def _encode(self):
jens@13:         "Generates the message's encoded form, prior to sending it."
jens@11:         out = StringIO()
jens@12:         for (key,value) in self.properties.iteritems():
jens@13:             def _writePropString(s):
jens@13:                 out.write(str(s))    #FIX: Abbreviate
jens@11:                 out.write('\000')
jens@12:             _writePropString(key)
jens@12:             _writePropString(value)
jens@13:         propertiesSize = out.tell()
jens@13:         assert propertiesSize<65536     #FIX: Return an error instead
jens@11:         
morrowa@51:         body = self.body or ""
jens@11:         if self.compressed:
jens@13:             z = zlib.compressobj(6,zlib.DEFLATED,31)   # window size of 31 needed for gzip format
jens@13:             out.write(z.compress(body))
jens@13:             body = z.flush()
jens@13:         out.write(body)
jens@13:         
jens@13:         self.encoded = struct.pack('!H',propertiesSize) + out.getvalue()
jens@13:         out.close()
jens@12:         log.debug("Encoded %s into %u bytes", self,len(self.encoded))
jens@11:         self.bytesSent = 0
jens@11:     
jens@14:     def _sendNextFrame(self, maxLen):
jens@11:         pos = self.bytesSent
jens@11:         payload = self.encoded[pos:pos+maxLen]
jens@11:         pos += len(payload)
jens@13:         self._moreComing = (pos < len(self.encoded))
jens@13:         if not self._moreComing:
jens@13:             self.encoded = None
jens@12:         log.debug("Sending frame of %s; bytes %i--%i", self,pos-len(payload),pos)
jens@12:         
jens@14:         header = struct.pack(kFrameHeaderFormat, kFrameMagicNumber,
jens@12:                                                    self.requestNo,
jens@12:                                                    self.flags,
jens@14:                                                    kFrameHeaderSize+len(payload))
jens@11:         self.bytesSent = pos
jens@14:         return header + payload
jens@11: 
jens@11: 
jens@12: class Request (object):
jens@12:     @property
jens@12:     def response(self):
jens@12:         "The response object for this request."
jens@13:         if self.noReply:
jens@13:             return None
jens@12:         r = self.__dict__.get('_response')
jens@12:         if r==None:
jens@12:             r = self._response = self._createResponse()
jens@12:         return r
jens@12: 
jens@11: 
jens@11: class Response (Message):
jens@13:     def _setRequest(self, request):
jens@12:         assert not request.noReply
jens@12:         self.request = request
jens@12:         self.requestNo = request.requestNo
jens@12:         self.urgent = request.urgent
jens@12:     
jens@11:     @property
jens@11:     def isResponse(self):
jens@11:         return True
jens@11: 
jens@11: 
jens@11: class IncomingRequest (IncomingMessage, Request):
jens@12:     def _createResponse(self):
jens@12:         return OutgoingResponse(self)
jens@11: 
jens@13: 
jens@11: class OutgoingRequest (OutgoingMessage, Request):
jens@12:     def _createResponse(self):
jens@12:         return IncomingResponse(self)
jens@13:     
jens@13:     def send(self):
jens@13:         self._encode()
jens@13:         return self.connection._sendRequest(self) and self.response
jens@13: 
jens@11: 
jens@11: class IncomingResponse (IncomingMessage, Response):
jens@12:     def __init__(self, request):
jens@13:         IncomingMessage.__init__(self,request.connection,None,0)
jens@13:         self._setRequest(request)
jens@12:         self.onComplete = None
jens@12:     
jens@12:     def _finished(self):
jens@12:         super(IncomingResponse,self)._finished()
jens@12:         if self.onComplete:
jens@12:             try:
jens@12:                 self.onComplete(self)
jens@12:             except Exception, x:
jens@12:                 log.error("Exception dispatching response: %s", traceback.format_exc())
jens@13: 
jens@13: 
jens@11: class OutgoingResponse (OutgoingMessage, Response):
jens@12:     def __init__(self, request):
jens@12:         OutgoingMessage.__init__(self,request.connection)
jens@13:         self._setRequest(request)
jens@13:     
jens@13:     def send(self):
jens@13:         self._encode()
jens@13:         return self.connection._sendMessage(self)
jens@11: 
jens@11: 
jens@13: """
jens@13:  Copyright (c) 2008, Jens Alfke <jens@mooseyard.com>. All rights reserved.
jens@13:  
jens@13:  Redistribution and use in source and binary forms, with or without modification, are permitted
jens@13:  provided that the following conditions are met:
jens@13:  
jens@13:  * Redistributions of source code must retain the above copyright notice, this list of conditions
jens@13:  and the following disclaimer.
jens@13:  * Redistributions in binary form must reproduce the above copyright notice, this list of conditions
jens@13:  and the following disclaimer in the documentation and/or other materials provided with the
jens@13:  distribution.
jens@13:  
jens@13:  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
jens@13:  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 
jens@13:  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRI-
jens@13:  BUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
jens@13:  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
jens@13:   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
jens@13:  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 
jens@13:  THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
jens@13: """