Re: [Taverna-users] Do I have to connect input data to every input port ?

[Stian Soiland-R. <soi...@cs...>]

On Fri, Sep 30, 2011 at 11:11, Sureerat Kaewkeeree <ma...@gm...> wrote:

> I've used gSoap to create web service server and gSoap supports using
> default values for omitted data.

> The problem is do I have to connect input data to every workflow input ports

As Christian points out, to workflow input ports [1] you will need to
provide every input as we've not got a mechanism for default workflow
values. This applies both when running a workflow (which could suggest
example values [2]), and when using the workflow as a nested workflow
- in which case all input ports need to be connected in the mother
workflow.


However on the service-level the reality is a bit different.  Some
services require you to provide a value for all inputs, and others
find reasonable defaults. If you have not connected a port to a WSDL
service, Taverna will try to avoid sending the required parameter if
it's allowed by the schema of the service, alternatively it will send
xsi:nil - and failing that it will send an empty string. (since
Taverna 2.2 - earlier versions might have always sent an empty strings
- even if say an xsd:int was expected)

If you want to force sending null to a WSDL service or an XML Input
Splitter (say as part of an input list), you can connect the input
port to a string constant with the magical value "xsi:nil" (without
the quotes). [3]  If you want to send a regular string, modify the
string constant or connect the port to an additional workflow port or
upstream service output port.

(Note that the xsi:nil trick only works for WSDL services and XML
input splitters - other services don't have a standardized way to
represent "null" or "nothing". )

[1] http://www.mygrid.org.uk/dev/wiki/display/taverna/Workflow+inputs+and+outputs
[2] http://www.mygrid.org.uk/dev/wiki/display/taverna/Example+values
[3] http://www.taverna.org.uk/documentation/faq/building-workflows/how-to-pass-null-to-a-web-service/


> I've also tried not to connect the input port to the workflow but it didn't
> work.

You might also have to delete the workflow input port if that's what
you are thinking off, although if it's not connected to anything in
the workflow it should not matter.

-- 
Stian Soiland-Reyes, myGrid team
School of Computer Science
The University of Manchester