krpc.py

   1 ## Copyright 2002-2003 Andrew Loewenstern, All Rights Reserved
   2 # see LICENSE.txt for license information
   3
   4 from bencode import bencode, bdecode
   5 from time import asctime
   6 import sys
   7 from traceback import format_exception
   8
   9 from twisted.internet.defer import Deferred
  10 from twisted.internet import protocol
  11 from twisted.internet import reactor
  12
  13 KRPC_TIMEOUT = 20
  14
  15 KRPC_ERROR = 1
  16 KRPC_ERROR_METHOD_UNKNOWN = 2
  17 KRPC_ERROR_RECEIVED_UNKNOWN = 3
  18 KRPC_ERROR_TIMEOUT = 4
  19
  20 # commands
  21 TID = 't'
  22 REQ = 'q'
  23 RSP = 'r'
  24 TYP = 'y'
  25 ARG = 'a'
  26 ERR = 'e'
  27
  28 class hostbroker(protocol.DatagramProtocol):
  29     def __init__(self, server):
  30         self.server = server
  31         # this should be changed to storage that drops old entries
  32         self.connections = {}
  33
  34     def datagramReceived(self, datagram, addr):
  35         #print `addr`, `datagram`
  36         #if addr != self.addr:
  37         c = self.connectionForAddr(addr)
  38         c.datagramReceived(datagram, addr)
  39         #if c.idle():
  40         #    del self.connections[addr]
  41
  42     def connectionForAddr(self, addr):
  43         if addr == self.addr:
  44             raise Exception
  45         if not self.connections.has_key(addr):
  46             conn = self.protocol(addr, self.server, self.transport)
  47             self.connections[addr] = conn
  48         else:
  49             conn = self.connections[addr]
  50         return conn
  51
  52     def makeConnection(self, transport):
  53         protocol.DatagramProtocol.makeConnection(self, transport)
  54         tup = transport.getHost()
  55         self.addr = (tup.host, tup.port)
  56
  57 ## connection
  58 class KRPC:
  59     noisy = 1
  60     def __init__(self, addr, server, transport):
  61         self.transport = transport
  62         self.factory = server
  63         self.addr = addr
  64         self.tids = {}
  65         self.mtid = 0
  66
  67     def datagramReceived(self, str, addr):
  68         # bdecode
  69         try:
  70             msg = bdecode(str)
  71         except Exception, e:
  72             if self.noisy:
  73                 print "response decode error: " + `e`
  74         else:
  75             #if self.noisy:
  76             #    print msg
  77             # look at msg type
  78             if msg[TYP]  == REQ:
  79                 ilen = len(str)
  80                 # if request
  81                 #       tell factory to handle
  82                 f = getattr(self.factory ,"krpc_" + msg[REQ], None)
  83                 msg[ARG]['_krpc_sender'] =  self.addr
  84                 if f and callable(f):
  85                     try:
  86                         ret = apply(f, (), msg[ARG])
  87                     except Exception, e:
  88                         ## send error
  89                         out = bencode({TID:msg[TID], TYP:ERR, ERR :`format_exception(type(e), e, sys.exc_info()[2])`})
  90                         olen = len(out)
  91                         self.transport.write(out, addr)
  92                     else:
  93                         if ret:
  94                             #   make response
  95                             out = bencode({TID : msg[TID], TYP : RSP, RSP : ret})
  96                         else:
  97                             out = bencode({TID : msg[TID], TYP : RSP, RSP : {}})
  98                         #       send response
  99                         olen = len(out)
 100                         self.transport.write(out, addr)
 101
 102                 else:
 103                     if self.noisy:
 104                         print "don't know about method %s" % msg[REQ]
 105                     # unknown method
 106                     out = bencode({TID:msg[TID], TYP:ERR, ERR : KRPC_ERROR_METHOD_UNKNOWN})
 107                     olen = len(out)
 108                     self.transport.write(out, addr)
 109                 if self.noisy:
 110                     print "%s %s >>> %s - %s %s %s" % (asctime(), addr, self.factory.node.port,
 111                                                     ilen, msg[REQ], olen)
 112             elif msg[TYP] == RSP:
 113                 # if response
 114                 #       lookup tid
 115                 if self.tids.has_key(msg[TID]):
 116                     df = self.tids[msg[TID]]
 117                     #   callback
 118                     del(self.tids[msg[TID]])
 119                     df.callback({'rsp' : msg[RSP], '_krpc_sender': addr})
 120                 else:
 121                     print 'timeout ' + `msg[RSP]['id']`
 122                     # no tid, this transaction timed out already...
 123             elif msg[TYP] == ERR:
 124                 # if error
 125                 #       lookup tid
 126                 if self.tids.has_key(msg[TID]):
 127                     df = self.tids[msg[TID]]
 128                     #   callback
 129                     df.errback(msg[ERR])
 130                     del(self.tids[msg[TID]])
 131                 else:
 132                     # day late and dollar short
 133                     pass
 134             else:
 135                 print "unknown message type " + `msg`
 136                 # unknown message type
 137                 df = self.tids[msg[TID]]
 138                 #       callback
 139                 df.errback(KRPC_ERROR_RECEIVED_UNKNOWN)
 140                 del(self.tids[msg[TID]])
 141
 142     def sendRequest(self, method, args):
 143         # make message
 144         # send it
 145         msg = {TID : chr(self.mtid), TYP : REQ,  REQ : method, ARG : args}
 146         self.mtid = (self.mtid + 1) % 256
 147         str = bencode(msg)
 148         d = Deferred()
 149         self.tids[msg[TID]] = d
 150         def timeOut(tids = self.tids, id = msg[TID]):
 151             if tids.has_key(id):
 152                 df = tids[id]
 153                 del(tids[id])
 154                 print ">>>>>> KRPC_ERROR_TIMEOUT"
 155                 df.errback(KRPC_ERROR_TIMEOUT)
 156         reactor.callLater(KRPC_TIMEOUT, timeOut)
 157         self.transport.write(str, self.addr)
 158         return d
 159