[Twisted-Python] dbapi and pb question

Sean Riley sean at twistedmatrix.com
Sat Aug 3 00:31:23 EDT 2002


looks to me like the method "perspective_echo" should return the defered
that the method "getAge" gets from  the dbapi.

Try changing:

   def perspective_echo(self, text):
        print 'echoing',text
        self.db.getAge(text).addCallback(self.gotAge,text)

to

   def perspective_echo(self, text):
        print 'echoing',text
        return self.db.getAge(text).addCallback(self.gotAge,text)


-----Original Message-----
From: twisted-python-admin at twistedmatrix.com
[mailto:twisted-python-admin at twistedmatrix.com]On Behalf Of Fredrik
Sent: Thursday, August 01, 2002 5:22 AM
To: twisted-python at twistedmatrix.com
Subject: [Twisted-Python] dbapi and pb question


I am a newbie to this  and i try to connect a database to pb,
when trying this code i dont get any response from the server (running
pbgtk.py)but the server outputs the print statement, how do I send bacdk a
callback to the client ??



from twisted.enterprise import adbapi
from twisted.spread import pb
from twisted.internet import app


class AgeDatabase(adbapi.Augmentation):
    """A simple example that can retrieve an age from the database"""

    def getAAge(self):
        sql = """SELECT age FROM person """
        return self.runQuery(sql)

    def getAge(self, name):
        sql = """SELECT age FROM person where name = %s """
        return self.runQuery(sql, name)

class DefinedError(pb.Error):
    pass

class SimplePerspective(pb.Perspective):
    db = AgeDatabase(adbapi.ConnectionPool("MySQLdb", db='test'))

    def perspective_echo(self, text):
        print 'echoing',text
        self.db.getAge(text).addCallback(self.gotAge,text)

    def perspective_error(self):
        raise DefinedError("exception!")

    #########################################
    # the next function wont return to client

    def gotAge(self,resultlist, name):
        age = resultlist[0][0]          # First field of first record
        print "%s is %d years old" % (name, age)
        return str(age)


class SimpleService(pb.Service):
    def getPerspectiveNamed(self, name):
        p = SimplePerspective(name)
        p.setService(self)
        return p

if __name__ == '__main__':
    import pbecho
    appl = app.Application("pbecho")

pbecho.SimpleService("pbecho",appl).getPerspectiveNamed("guest").makeIdentit
y("guest")
    appl.listenTCP(pb.portno, pb.BrokerFactory(pb.AuthRoot(appl)))
    appl.run()
    #appl.save("start")



Fredrik Bjornsson
info at cleosan.com


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