#! /usr/bin/python

from twisted.spread import pb, jelly
from twisted.python import log
from twisted.internet import reactor

class MyException(pb.Error): pass
class MyOtherException(pb.Error): pass

class ScaryObject:
    # not safe for serialization
    pass

def worksLike(obj):
    # the callback/errback sequence in class One works just like an
    # asynchronous version of the following:
    try:
        response = obj.callMethod(name, arg)
    except pb.DeadReferenceError:
        print " stale reference: the client disconnected or crashed"
    except jelly.InsecureJelly:
        print " InsecureJelly: you tried to send something unsafe to them"
    except (MyException, MyOtherException):
        print " remote raised a MyException" # or MyOtherException
    except:
        print " something else happened"
    else:
        print " method successful, response:", response

class One:
    def worked(self, response):
        print " method successful, response:", response
    def check_InsecureJelly(self, failure):
        failure.trap(jelly.InsecureJelly)
        print " InsecureJelly: you tried to send something unsafe to them"
        return None
    def check_MyException(self, failure):
        which = failure.trap(MyException, MyOtherException)
        if which == MyException:
            print " remote raised a MyException"
        else:
            print " remote raised a MyOtherException"
        return None
    def catch_everythingElse(self, failure):
        print " something else happened"
        log.err(failure)
        return None

    def doCall(self, explanation, arg):
        print explanation
        try:
            deferred = self.remote.callRemote("fooMethod", arg)
            deferred.addCallback(self.worked)
            deferred.addErrback(self.check_InsecureJelly)
            deferred.addErrback(self.check_MyException)
            deferred.addErrback(self.catch_everythingElse)
        except pb.DeadReferenceError:
            print " stale reference: the client disconnected or crashed"

    def callOne(self):
        self.doCall("callOne: call with safe object", "safe string")
    def callTwo(self):
        self.doCall("callTwo: call with dangerous object", ScaryObject())
    def callThree(self):
        self.doCall("callThree: call that raises remote exception", "panic!")
    def callShutdown(self):
        print "telling them to shut down"
        self.remote.callRemote("shutdown")
    def callFour(self):
        self.doCall("callFour: call on stale reference", "dummy")
        
    def got_obj(self, obj):
        self.remote = obj
        reactor.callLater(1, self.callOne)
        reactor.callLater(2, self.callTwo)
        reactor.callLater(3, self.callThree)
        reactor.callLater(4, self.callShutdown)
        reactor.callLater(5, self.callFour)
        reactor.callLater(6, reactor.stop)
        
deferred = pb.getObjectAt("localhost", 8800, 30)
deferred.addCallback(One().got_obj)
reactor.run()