Continue workflow when node is inactive

Dear KNIMERs,
I am facing a problem with inactive nodes which I thought is easy to deal with, but I failed to find a solution. I have a workflow where a user can select several files, one for each of a replicated analysis. The workflow is enwrapped in a component and the user can upload up to three files. But I would like the workflow to continue if only two files are uploaded. In the latter case one of the file upload nodes produces an inactive branch. I tried to use “if switches”, “error catches” etc. - in order to trigger the workflow to produce an error message in case that the file uploads fails and to continue the workflow with an error message. I.e. this error message would be included in a concatenated table that combines or joines with the information from the uploaded files.
Is there any switch that allows to trigger a node in case of an inactive branch? Or is there a variable that can be extracted from an inactive branch to provide a value for a case switch?
Thanks for your help in advance
Stefan
I have uploaded an example workflow.
Read one or more files.knwf (116.3 KB)

If the user has to upload one you can use a case switch end

Hi Iris,
this looks indeed like a very simple solution. It works on KNIME analytical platform, but it fails when I try this on KNIME server or KNIME portal, respectively. Is there any possibility to implement this for a workflow that is used via KNIME portal? I.e. the user would be offered theoretically more than 1 possibility for file upload but the workflow should not fail when only on file is uploaded.
Thanks for any hint in advance.
Stefan
Read one or more files case switch

Hi @sscholz

on which KNIME Server Version are you?
Because you are using Quickforms and I wanted to check before changing this to widgets.
Best, Iris

Hi Iris,
I think we are using the latest version (compatible with KNIME Analytics Platform 4.2.4, not compatible with 4.3). I tried with widgets as well, but the problem is the same.
Stefan

Hi @sscholz

I made you an example

I need to check with the dev team, but you need to provide a default file when the file is optional. What I did is writing an empty file in the workflow and use this in case none is selected. You could also just read a file on the server as default. The workflow above allowed me to upload only one of the three filles.

I would read the files after the upload component. That makes it easier to debug if any problem appears.

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Hi Iris,
unfortunately I cannot reproduce the workflow provided as it seems to be in a different (Knime 4.3) version. I have only create temp dir available and also not the path to string (variable) is not available. I tried to setup the workfow similar using the knime 4.2.4 nodes. The workflow is running without errors but I do not get any data, i.e. the subsequent table view nodes do not show up when I use the dummy files. Can a version compatible to 4.2.4 (Knime Analytics) be provided to make sure I have the correct configurations?
Kind regards
Stefan

Hi Stefan,

I’m sorry it took this long, but maybe also for future readers I tried myself at a 4.2.4 compatible version:

Kind regards
Marvin

Hi @sscholz,
i have i similar problem with multiple data sources which not in all cases return data. I solved that issue by using of the empty table switch node followed by an end if node.

BR

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