[Rails] (no subject)

[Scott Willson]

My application has one central database + Rails server and many  
distributed GUI clients. The remote clients need to read and update  
different collections of ActiveRecords. They also need to submit  
fairly demanding calculation + database update requests.

Have you designed a similar Ruby application? What did you do?

I'll try to summarize the approachs I'm considering without putting  
you to sleep with the details.

Rails Web Service. Built in to the Rails framework. Interoperable  
with other applications. Easy to get through firewalls/proxy. But I  
don't care about interoperability. How fast is XML marshaling/ 
unmarshaling? Probably requires that I recreate a subset of my domain  
model in Structs.

DRb + DRbUndumped. Send ActiveRecords across as remote proxies. Easy  
to set up. Faster than XML. Can re-use ActiveRecord. A bit tricky to  
get right -- where is that method being called? Won't every method  
call be a remote call in this design? This fine-grained remote  
interface approach didn't pan out so well with remote EJBs, to say  
the least.

DRb + pass ActiveRecords by value. DRb creates a local copy of each  
remote ActiveRecord. Coarse-grained remote interface. Can use  
ActiveRecord methods locally for formatting, calculations, etc. Big  
drawback: ActiveRecord expects a working database connection. It uses  
the database connection to "magically" add association methods at  
runtime. Requires considerable ActiveRecord hacking.

DRb + custom remote models. Use "service" classes that convert  
ActiveRecords to and from remote-friendly domain classes. Precise  
control of what is sent to the remote client. Doesn't try to force  
ActiveRecord into something it's not. But we're back to recreating  
our domain model again. Maybe I should just crack open my Core J2EE  
Patterns book.

XML-RPC/SOAP. XML marshalling and SOAP complexity with all the  
drawbacks of the DRb approach.

There's not a lot out there, but the best summary I've found is this  
PDF:
http://www.vanruby.com/system/files?file=20051025-soap4r- 
emil_marceta.pdf

Thanks for any thoughts or feedback!
Scott