Molecule Widget (Labs) not working on KNIME Server 4.16.5

Hi everybody,
As described in this thread, the Molecule Widget (Labs) node has advantages compared to the Molecule Widget node.

As described on the mentioned thread, the Molecule Widget (Labs) should work on the KNIME Server 4.16.5. Unfortunately we updated to this version of the server and we found that the node it’s not working.

The following errors are triggered in the WebPortal (see also attached screenshot):

  • Ketcher object not defined.
  • ERROR: Molecule Widget (Labs)
  • View validation failed.

Does anybody have any suggestions to make the Molecule Widget (Labs) node working on the KNIME Server?



Hi @gcincilla

That doesn’t look good, let me look into that. I’ll keep you updated

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@gcincilla What’s the executor version that you are on? Mine is 5.1 and I get this:

Which is another problem, but not what you are seeing, so right now I cannot replicate your issue.

@Alice_Krebs, thanks for your prompt reply and help. We’re currently using version 4.7 of the executor. Will updating to the 5.1 solve the problem?
The javascript view you’re getting is exactly the one I got. If you try to click next, then probably you’ll see the error messages I uploaded with my screenshot.
Your help is greatly appreciated.

@gcincilla Just FYI, I’m on it, but that will probably bleed into next week. Keeping you posted :slight_smile:

Great @Alice_Krebs , thanks for letting me know!

Hey @gcincilla,

you also need to have 5.1 as executor, otherwise it cannot work.
Let me know if this fixes the problem :slight_smile:


Thank you Daniel. I’ll try to update the executor and will report the result on this thread.

Hey @gcincilla,

I just noticed a different problem, which is probably the main cause you are seeing this error. With the new sketcher version they now require/use webworkers to allow the full functionality. These webworkers are not allowed by our default CSP header we set for the KNIME server. To allow this there is a configuration option in the KNIME server config called: “com.knime.server.webportal.csp” where you have to allow these types here: worker-src ‘unsafe-inline’ ‘unsafe-eval’ ‘self’ blob:; connect-src data: ‘self’;
an example CSP could look something like this:
com.knime.server.webportal.csp: default-src 'self'; script-src 'unsafe-inline' 'unsafe-eval' 'self'; style-src 'unsafe-inline' 'self'; img-src 'self' data:; worker-src 'unsafe-inline' 'unsafe-eval' 'self' blob:; connect-src data: 'self';



(which for me meant simply adding worker-src 'unsafe-inline' 'unsafe-eval' 'self' blob:; connect-src data: 'self'; at the end to what was already there)


Thank you @DanielBog for noticing this and @Alice_Krebs for following this issue.
In this case I’ll try to configure the server in that way and running with the old (v.4.7) executor.
I’ll post the result in this thread.

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Hi @DanielBog and @Alice_Krebs, I apologise for the delay.
I can confirm that the solution provided by Daniel solves the problem and allows us to use Molecule Widget (Labs) on the KNIME server.
Thank you very much for this! I appreciated it very much.


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