[AG-TECH] AGTk Development: Can a Shared Application Run on a PC without a Venue Client?

[Allan Spale]

Justin,

Would it not be simpler to create a service (this is more of a
prove-why-I-am-wrong question rather than questioning your work and
approach)?  The shared application I need uses venue data (which makes it
usage as a shared application more obvious), but there is not any
collaboration using event channels (which seems to make its usage as a
shared application less obvious).  Having an AG service would just involve
implementing start, stop, configrure, and any other method that may be
relevant to the viewer because I do not programmatically manipulate the
viewer (as in SharedPresentation with going to next slide, going to
previous slide, etc.).  So, why would my viewer still be best implemented
as a shared application rather than a service? 

Thanks for your patience.


Allan

On Wed, 4 Jun 2003, Justin Binns wrote:

> Hmm, so I don't really have the VenueVNC stuff packaged in a way that I'd 
> be happy with other folks poking - I'll see if I can't get it wrapped up.  
> In the mean time, the process is really quite simple - I just set up a 
> little python script that runs as a daemon (completely outside AGTk) that 
> responds to remote proceedure calls (I used XMLRPC, you could use the 
> GSI-SOAP that comes with the AGTk if you'd like) by doing things like 
> spawning viewers, running programs, etc.  Then my shared app just has to 
> make the appropriate RPC calls, and the daemons run the bits I need.  The 
> Venue Client, after all, just executes the configured command in response 
> to a mime-type match, all I do is propagate that execution over the wire.  
> 
> Justin
> 
> On Wed, 4 Jun 2003, Allan Spale wrote:
> 
> > Justin,
> > 
> > I really appreciate your response.  I will take a look at the VNCWall and
> > XML stuff.  Is the code for VenueVNC posted somewhere that I could look at
> > how you addressed the problem?
> > 
> > In general, given that the world of shared applications is not as
> > straightforward for some cases, would a future version of the AGTk contain
> > some APIs that would make this process easier, or would it be possible for
> > me, as I am working (and if it would acutally be helpful to me), to create
> > some APIs off of the AGTk to facilitate people's future work in this
> > direction?
> > 
> > Thanks for your time.
> > 
> > 
> > Allan
> > 
> > On Wed, 4 Jun 2003, Justin Binns wrote:
> > 
> > > Allan,
> > > 	In my experience in coding the VenueVNC "shared application", I
> > > looked at similar problems (when integrating the tiled display).  The
> > > simple answer to your question is that the Venue Client is not necessary
> > > for the shared application to run, though an AGTk installation is, of
> > > course, required.  The way I did it with the Tiled Display with VenueVNC
> > > was to have a separate mechanism for interacting with the Tiled Display (a
> > > set of Python/XMLRPC applications/daemons that allowed operations similar
> > > to the VNCWall stuff from NCSA), and a separate client that knew how to 
> > > make use of the TD stuff to launch my client code remotely (on the Tiled 
> > > Display nodes) instead of locally.  Does that help?
> > > 
> > > Justin
> > > 
> > > On Wed, 4 Jun 2003, Allan Spale wrote:
> > > 
> > > > Hello,
> > > > 
> > > > In my efforts to try to further understand developing AG add-ons using the
> > > > AGTk, I was wondering if it is possible to run a shared application on a
> > > > PC in the group/cluster of PCs that encompass the AG node.  For instance,
> > > > I am trying to integrate a 3-D model viewer application into AG 2 as a
> > > > shared application.  After chatting with Tom Uram on the MUD (thanks, Tom)
> > > > about all my questions about the difference between an AG service and
> > > > shared application, it seemed like writing a shared application was the
> > > > way to go.
> > > > 
> > > > However, there are some wrinkles in this seemingly simple application. 
> > > > First, the shared app requires access to a file in the venue (provided by
> > > > specifying URLs to the actual location of the files) that consist of the
> > > > model being viewed or a set of files for viewing a series of models at one
> > > > time and a configuration file.  This is not a problem.  When I would
> > > > choose the file from the venue, it would have a MIME type associated with
> > > > the viewer application (the MIME type would be registered during the
> > > > installation of the viewer) on the PC running the venue client.  If there
> > > > is a need to share the same view of the model, it is provided through
> > > > using an event server created specifically for this 3-D model viewer (so I
> > > > am not using an event channel for the shared application, which seems
> > > > conterintutitive...it is a shared application, but the AGTk is not used to
> > > > announce events to the viewer application).
> > > > 
> > > > So, it seemed like I understood what I wanted to do until I realized
> > > > something...the 3-D model viewer application needs to run on another PC,
> > > > which would not run a venue client.  This leads to my question: can a
> > > > shared application running on a PC with a venue client launch the
> > > > application being shared on a PC where the venue client is not running?
> > > > This other PC, where the 3-D model viewer must run, is connected to a
> > > > passive stereo display (GeoWall).  Now, does this new requirement
> > > > prohibit me from integrating this viewer as a shared application and
> > > > necessitate that it is now a service?  Or, is it still a shared
> > > > application where the user would install the viewer executable (being
> > > > shared) on the PC connected to the passive stereo system and somehow the
> > > > shared program running on the PC with the venue client would know to
> > > > launch that application on the other PC through some programmatic means? 
> > > > 
> > > > Any help/advice would be appreciated.
> > > > 
> > > > 
> > > > Allan
> > > > EVL at UIC
> > > > Research Assistant
> > > > 
> > > > 
> > > > 
> > > 
> > 
> > 
>