Show appropriate offline messages when no internet connection

Summary

There is no distinction between the "resource not found" state (solved in !41 (merged) / #76 (closed) ) of the app and the "cannot load the resource because of no internet connection".

Steps to reproduce

  1. Open the app (after !41 (merged) merged or in !41 (merged))
  2. Go to search
  3. Open developer tools in the browser, go to network tab and switch from online to offline
  4. Click any item in the search list

What is the current bug behavior?

"Not found" message appears although the resource exists and only cannot be loaded as there is no internet connection.

What is the expected correct behavior?

The app should behave differently when there is no internet connection and is not sure that a resource is a existing one or not.

Relevant logs and/or screenshots

not-found

Possible fixes

  1. The app should try to load the resource
  2. the app should show the message that there is currently no internet connection
  3. the app should try connecting/loading the resource and succeed when there is internet connection again