[Twisted-Python] Twisted Enterprise (newbie question)

[Steve Waterbury]

Glyph Lefkowitz wrote:
> 
> From: Steve Waterbury <steve.waterbury at gsfc.nasa.gov>
> Subject: Re: [Twisted-Python] Twisted Enterprise (newbie question)
> Date: Thu, 23 May 2002 11:36:48 -0400
> 
> > So I created a "runQuery" method for adbapi.ConnectionPool:
> >
> >     def runQuery(self, *args, **kw):
> >         d = defer.Deferred()
> >         apply(self.query, (d.callback,d.errback)+args, kw)
> >         return d
> >
> > ... and now my script works!  (Has adbapi.ConnectionPool been fixed yet
> > in the CVS version?)
> 
> You probably want to be using adbapi.Augmentation; which, curiously enough, has
> a method "runQuery" ...
> 
> 
>     def runQuery(self, *args, **kw):
>         d = defer.Deferred()
>         apply(self.dbpool.query, (d.callback, d.errback)+args, kw)
>         return d
> 
> ... that looks an awful lot like what you want :-)  ...

Oops ... I *was* using Augmentation (as did the example):

Steve Waterbury wrote:
> Here's the new version of my script (assumes the process owner's
> login name is also a database user):
> --------------------------------------------------------------------------
> from twisted.internet import main
> from twisted.enterprise import adbapi
> import sys
> class TestDatabase(adbapi.Augmentation):
>     ...

... but when I looked in adbapi, I forgot which one I was looking at!
My script works just fine with the original adbapi ... doh!  
  
So adbapi is okay, but the example in "Introduction to Twisted Enterprise" 
( http://twistedmatrix.com/documents/howto/enterprise ) should be 
corrected, I think:

    class AgeDatabase(adbapi.Augmentation): 
        """A simple example that can retrieve an age from the database""" 
        def getAge(self, name): 
            # Define the query 
            sql = """SELECT Age FROM People WHERE name = ?""" 
            # Run the query, and return a Deferred to the caller to add 
            # callbacks to. 
HERE >>     return self.runOperation(sql, name) 
                        ^^^^^^^^^^^^
....................... should be "runQuery", in order for "resultlist" to work,
and ...

    def gotAge(resultlist, name): 
        """Callback for handling the result of the query""" 
        age = resultlist[0][0]          # First field of first record 
        print "%s is %d years old" % (name, age) 

HERE >>
    db = MyDatabase(dbpool) 
         ^^^^^^^^^^
........ should be "AgeDatabase"
 
    # These will *not* block.  Hooray! 
    db.getAge("Andrew").addCallbacks(gotAge, db.operationError, 
                                     callbackArgs=name).arm() 
    db.getAge("Glyph").addCallbacks(gotAge, db.operationError, 
                                    callbackArgs=name).arm() 

-- Steve.

Stephen C. Waterbury  http://misspiggy.gsfc.nasa.gov/people/waterbug.html
    "An idiot with a computer is a faster, better idiot." - Rick Julius