Harvesting client not compatible with servers using HTTP

Hello,

I tried to harvest an OAI server compatible with the HTTP protocol,
e.g. : http://cds.unistra.fr/registry/?verb=ListIdentifiers&metadataPrefix=oai_dc

When creating a harvesting client, Dataverse seems to say that HTTP is supported:

Tested with the devleop branch, it is not possible to fill in an OAI server with the HTTP protocol :

It is however possible to declare a harvesting client with the API and fill in an OAI server with the HTTP protocol.
In this case, an error is raised during harvesting :

Caused By Exception.................... java.nio.channels.UnresolvedAddressException null
StackTrace: 
java.base/sun.nio.ch.Net.checkAddress(Unknown Source)
java.base/sun.nio.ch.Net.checkAddress(Unknown Source)
java.base/sun.nio.ch.SocketChannelImpl.checkRemote(Unknown Source)

Two choices are possible:

1. Support HTTP protocol
2. Indicate that the url must start with https://...

Any related open or closed issues to this bug report?
https://github.com/IQSS/dataverse/issues/4831

Are you thinking about creating a pull request for this issue?
This is not planned by the team at the moment !

Reproduce the harvesting-client flow with the HTTP OAI server URL from the report, then trace both client creation and the harvesting request that produces UnresolvedAddressException. Review related issue #4831 and determine whether HTTP should work or be rejected with an explicit HTTPS requirement. Done means the chosen behavior is consistent in the UI, API, and harvesting path.