[Activerdf] YARS connection error

[Eyal Oren]

On 07/19/06/07/06 14:34 +0200, Ingo Paulsen wrote:
>Hi,
>
>I've installed the yars.war file in my tomcat webapps directory.
sorry for the delay.

>When I'm trying to connect from irb to the yars data-store I got this 
>error message for the first time:
>
>irb(main):001:0> require 'active_rdf' >=> true
>irb(main):002:0> NodeFactory.connection( :adapter => :yars, :context => 
>'yars', :host => 'localhost' )
>NoMethodError: undefined method `size' for false:FalseClass from 
>/usr/local/lib/ruby/1.8/active_rdf/src/node_factory.rb:406:in 
>`construct_class_model' from 
>/usr/local/lib/ruby/1.8/active_rdf/src/node_factory.rb:155:in 
>`init_adapter' from 
>/usr/local/lib/ruby/1.8/active_rdf/src/node_factory.rb:109:in `connection'
>from (irb):2
>irb(main):003:0> NodeFactory.connection( :adapter => :yars, :context => 
>'yars', :host => 'localhost' )
>=> #<YarsAdapter:0x5d4364 @port=8080, @host="localhost", 
>@adapter_type=:yars, @yars=#<Net::HTTP localhost:8080 open=false>, 
>@context="yars", @query_language="n3">

>The second time it works. What's the reason for this behaviour?
>Am I missing some basic adjustment to have a connection to YARS?
No, I think this is a bug, either in YARS or in our adapter.
The error "undefined size for false:FalseClass" is because the YARS adapter 
cannot connect to the YARS database (it does not receive an HTTP::OK from 
YARS). Could you look into the log (should be at /tmp/activerdf.log) and 
try to locate the query response from YARS?

Another thing you could try is just connecting to YARS from a browser, 
http://localhost:8080/yars and see what you get. You should get a blank 
page (HTTP::NoContent) if the datastore is empty, otherwise you should just 
see the triples in the datastore.  That will tell us whether the problem is 
at the YARS-end or in ActiveRDF.

 -eyal