Mongrel users - Feb 2007 - Passing XMLRPC errors on to clients

Hi,

I''m experimenting with using Mongrel to serve XMLRPC, and I''m
having
trouble passing the XMLRPC errors on to the client.

In my webrick implementation, I just raise the XMLRPC error and the  
client receives it and can handle it like a normal exception.  With  
Mongrel, when I raise the error, Mongrel catches it and just closes  
the client connection, which means the client gets a very  
uninformative EOF instead of a useful error message.

Has anyone on the list found a way to effectively pass the error on  
to the client?  If not, can someone recommend a place for me to start  
looking at how to do it?

It looks like I could try overriding the ''process_client''
method in
the HttpServer class, but I''d still need to know how to convert the  
error into a valid XMLRPC error, which somehow the webrick stuff just  
does for me.  Clearly this might be a necessity, but I''m hoping I can  
leave the error handling to the libraries instead of doing it myself.

If anyone is interested in how I''m doing it right now, you can check  
the source of the mongrel class I''ve written[1] and the xmlrpc_server  
class[2].  I''m not going to say any of this code is "good",
but I''ve
seen a dearth of examples and I''m doing what I can.

Any help is muchly appreciated.

1 - https://reductivelabs.com/trac/puppet/browser/branches/ 
webserver_portability/lib/puppet/network/server/mongrel.rb
2 - https://reductivelabs.com/trac/puppet/browser/branches/ 
webserver_portability/lib/puppet/network/xmlrpc_server.rb

  --
  Sometimes I think we''re alone. Sometimes I think we''re not.
In
  either case, the thought is staggering.   --R. Buckminster Fuller
  ---------------------------------------------------------------------
  Luke Kanies | http://reductivelabs.com | http://madstop.com

On Sun, 18 Feb 2007 14:46:36 -0600
Luke Kanies <luke at madstop.com> wrote:
> Hi,
> 
> I''m experimenting with using Mongrel to serve XMLRPC, and
I''m having
> trouble passing the XMLRPC errors on to the client.
> 
> In my webrick implementation, I just raise the XMLRPC error and the  
> client receives it and can handle it like a normal exception.  With  
> Mongrel, when I raise the error, Mongrel catches it and just closes  
> the client connection, which means the client gets a very  
> uninformative EOF instead of a useful error message.
The contract a handler has with Mongrel is the handler must handle
*all* exceptions.  If any are leaked to Mongrel it''s bad news and the
connection is closed.  Period.

If you look at your webrick code you''ve got several places where you
catch the exceptions you want, but none of this code in the Mongrel
version.

Since XMLRPC requires that exceptions be translated into an XML fault
format, you''ll have to write that.  Mongrel can''t do it.

Hope that helps.

-- 
Zed A. Shaw, MUDCRAP-CE Master Black Belt Sifu
http://www.zedshaw.com/
http://www.awprofessional.com/title/0321483502 -- The Mongrel Book
http://mongrel.rubyforge.org/
http://www.lingr.com/room/3yXhqKbfPy8 -- Come get help.