How can I establish communication with a Solargraph LSP instance.

[KarlHeitmann]

I want to know how an LSP works. Before coming here, I've tried to run rubocop --lsp and tried to build a script to send commands to that instance, but was unsuccessful (scarce documentation and examples on the source code). I decided to jump to Solargraph, but still I am unsuccessful to establish communication with the solargraph instance.

I want to know how an LSP works because I want to build a ruby CLI tool that communicates with LSP servers (can be either Solargraph or Rubocop).

I found this library language_server-protocol that rubocop uses when it is run as LSP. Can I use that gem to build a script to communicate with Solargraph? I've found this test file: spec/source_map/mapper_spec.rb that has some nice examples to know how the Solargraph code works, but I need to build something like this:

require 'language_server-protocol'
writer = LanguageServer::Protocol::Transport::Io::Writer.new(port: "xxxx", host: "localhost")
result = writer.send({ command: "autocomplete", path: "main.rb", extra: {user_input: "foo"} })

puts result
# I see on stdout the list of the auto complete menu

Any tips, hints and examples about establishing communication with the LSP server will be much appreciated.