What happened

Accidentally omitting document content returns 500 Internal Server Error with a body of {"message":"Internal error","uri":"/new_index"}

What was expected

Emitting any kind of helpful message would be helpful. Also, in my experience, when the client receives a 500 response, there is usually something informative on the server-side. But in this case, the server e

I have dropped this feature when porting Thinlet UI to JavaFX (later, replaced by Swing.)

Thinlet Lule has "Tools > Export" menu. This wiki describes the feature.
https://github.com/DmitryKey/luke/wiki/Exporting-index-to-xml

I would like to re-think this feature (but cannot take enough time for this now.)
When (re)implementing this feature, file format selection (e.g. export to xml, json o

Describe the issue

#90 and #94 introduced example apps, but the build pipeline was not updated.

The azure-pipelines.yml needs to updated to make sure they compile.