How to implement an intermediate completing read before running the selected code action?

[chahak13]

Hello! Thank you for working on eglot!

Some contex:

I'm working on a simple SQL Language Server and one feature that I want to include is the ability to switch the database connection that the query on point executes in (think test database, eval database etc.). I am exposing this Switch Connection function as a code action from the Language Server.

Question:

The workflow that I want to achieve looks something like this -

1. The user selects switchConnections code action
2. eglot requests the server for the response to showConnectionAliases and shows the responses in a completing-read menu
3. The user selects the connection alias they want
4. eglot sends the switchConnections action with the selected alias as an argument to the language server.

I'm not sure how to go about this in eglot. Any suggestions or guidance would be very helpful!

Or more generally, if I want to extend or advice eglot to provide extra functionality for a language server, how should I do that? I can then share those as separate patches without having to add those server specific changes to eglot :)