ServiceObject.IsValid() method

[Ivan R. Judson]

Another thing that comes to mind that would make the venue server startup
easier would be some call (perhaps via the hosting environment) to return
the authorization information of the user running the process.

This I'd see as useful for the first time a venue server is run,
automatically filling in the adminstrators list with the first
administrator.

Thoughts?

--Ivan

PS -- Thoughts on my previous email below?

> -----Original Message-----
> From: owner-ag-dev at mcs.anl.gov 
> [mailto:owner-ag-dev at mcs.anl.gov] On Behalf Of Ivan R. Judson
> Sent: Saturday, February 08, 2003 4:35 PM
> To: 'Robert Olson'; 'AG Dev'
> Subject: RE: ServiceObject.IsValid() method
> 
> 
> 
> Because validating a url connects to an object is a more 
> direct solution than handling an error on an enter call (oh, 
> you can't enter *that*, that's not a valid client proxy.
> 
> Fwiw, if the get_proxy() isn't validating that the url points 
> to a real object, there are some serious semantic 
> ramifications -- that is you *never* know if the client proxy 
> is actually valid -- which seems fundamentally wrong, doesn't 
> it? If the url passed to Client().get_proxy() isn't valid 
> shouldn't it at least throw an exception? Or return None?
> 
> Look at bin\VenueClient.py -> GoToNewVenue(..args..), where 
> this all started from.
> 
> --Ivan
> 
> > -----Original Message-----
> > From: Robert Olson [mailto:olson at mcs.anl.gov]
> > Sent: Saturday, February 08, 2003 2:56 PM
> > To: judson at mcs.anl.gov; 'AG Dev'
> > Subject: RE: ServiceObject.IsValid() method
> > 
> > 
> > At 02:50 PM 2/8/2003 -0600, Ivan R. Judson wrote:
> > 
> > >Yeah, I don't expect this is one of those 'use it all the
> > time' things,
> > >but for example to verify that a venue url actually maps to
> > a venue the
> > >first time would make the code a lot less twisty and turny.
> > 
> > I don't see how it'd be less turny to call IsWhatever and
> > handle the error 
> > case than to call the method you want and handle the exception.
> > 
> > >I can't think of any other cases, actually.
> > >
> > >--Ivan
> > >
> > > > -----Original Message-----
> > > > From: Robert Olson [mailto:olson at mcs.anl.gov]
> > > > Sent: Saturday, February 08, 2003 2:33 PM
> > > > To: judson at mcs.anl.gov; 'AG Dev'
> > > > Subject: RE: ServiceObject.IsValid() method
> > > >
> > > >
> > > > Hm. The price you pay is an expensive roundtrip to verify if you
> > > > have the object you're looking for, rather than just 
> handling the
> > > > exception when you
> > > > have it wrong.
> > > >
> > > > --bob
> > > >
> > > > At 01:55 PM 2/8/2003 -0600, Ivan R. Judson wrote:
> > > >
> > > > >I don't know. The behavior I'm trying to avoid is that a
> > > > client object
> > > > >(result of ...get_proxy() isn't really anything until a call
> > > > is made,
> > > > >but if that call fails your down the error handling path
> > -- you'd
> > > > >really like to know if the handle is valid ahead of 
> time in some
> > > > >cases...
> > > > >
> > > > >Does that make it any more clear?  The words that come to
> > > > mind are "you
> > > > >want to know you have a valid proxy object before you use
> > > > it", but I'm
> > > > >not sure that helps make it more clear :-)
> > > > >
> > > > >--Ivan
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Robert Olson [mailto:olson at mcs.anl.gov]
> > > > > > Sent: Saturday, February 08, 2003 1:38 PM
> > > > > > To: judson at mcs.anl.gov; 'AG Dev'
> > > > > > Subject: Re: ServiceObject.IsValid() method
> > > > > >
> > > > > >
> > > > > > is that doing the same thing as isinstance(obj,
> > ServiceObject) ?
> > > > > >
> > > > > > At 01:32 PM 2/8/2003 -0600, Ivan R. Judson wrote:
> > > > > > >I propose we add amethod IsValid() to the service object
> > > > > > that returns
> > > > > > >true. Then you can verify that your handle is good *before*
> > > > > > you try to
> > > > > > >use it. This makes it significantly easier to handle cases
> > > > > > like venue
> > > > > > >entering...
> > > > > > >
> > > > > > >Thoughts?
> > > > > >
> > > >
> > 
>