Can't add ncWMS endpoint to ESRI web app

[rsignell-usgs]

I tried going to the Wetlands Synthesis Portal at http://arcg.is/2nZ0A1Q (built with ESRI App Builder), clicked the "Add Data" icon and tried to add this THREDDS ncWMS endpoint:

http://geoport-dev.whoi.edu/thredds/wms/sand/usgs/users/zdefne/run076/00_dir_roms.ncml?SERVICE=WMS&REQUEST=GetCapabilities&VERSION=1.3.0

The app gives a 500 error, and using the developer tools shows that it's issuing this request:
https://usgs.maps.arcgis.com/sharing/proxy?http://geoport-dev.whoi.edu/thredds/wms/sand/usgs/users/zdefne/run076/00_dir_roms.ncml?SERVICE=WMS&REQUEST=GetCapabilities&VERSION=1.3.0

@zdefne-usgs, can you try to figure out why?

[zdefne-usgs]

The address of the layer to add is http, but the resulting request generated automatically is for https.

[rsignell-usgs]

Ah, interesting. I wonder why App Builder is doing that. Can you do a google search to see if that's a known bug and report back here?

[zdefne-usgs]

I did a bit of a web search on it, but couldn't come across anything related. Left a comment for Esri on the tool's page...

[zdefne-usgs]

Actually, this looks related...
"Yes. Web AppBuilder supports SSL-enabled access to online organizations or Portal for ArcGIS. The HTTPS request is required when the URL to the organization or Portal for ArcGIS is specified."
https://developers.arcgis.com/web-appbuilder/guide/faqs.htm