Prototype LSP Rails runner

lib/ruby_lsp/ruby_lsp_rails/addon.rb

@@ -6,6 +6,7 @@
 require_relative "rails_client"
 require_relative "hover"
 require_relative "code_lens"
+require "open3"
 
 module RubyLsp
   module Rails
@@ -20,10 +21,52 @@ def client
       sig { override.params(message_queue: Thread::Queue).void }
       def activate(message_queue)
         client.check_if_server_is_running!
+        @stdin, @stdout, @stderr, @wait_thread = Open3.popen3("bin/rails runner lib/ruby_lsp/ruby_lsp_rails/server.rb")
+
+        @stdin.binmode
+        @stdout.binmode
       end
 
       sig { override.void }
-      def deactivate; end
+      def deactivate
+        make_request("shutdown")
+
+        @stdin.close
+        @stdout.close
+        @stderr.close
+      end
+
+      def make_request(request, params = nil)
+        send_request(request, params)
+        read_response(request)
+      end
+
+      def send_request(request, params = nil)
+        hash = {
+          id: rand(100),
+          method: request,
+        }
+
+        hash[:params] = params if params
+        json = hash.to_json
+        @stdin.write("Content-Length: #{json.length}\r\n\r\n")
+        @stdin.write(json)
+      end
+
+      def read_response(request)
+        Timeout.timeout(5) do
+          # Read headers until line breaks
+          headers = @stdout.gets("\r\n\r\n")
+
+          # Read the response content based on the length received in the headers
+          raw_response = @stdout.read(headers[/Content-Length: (\d+)/i, 1].to_i)
+
+          json = JSON.parse(raw_response, symbolize_names: true)
+          warn("*** response ***: #{json}")
+        end
+      rescue Timeout::Error
+        raise "Request #{request} timed out. Is the request returning a response?"
+      end
 
       # Creates a new CodeLens listener. This method is invoked on every CodeLens request
       sig do

lib/ruby_lsp/ruby_lsp_rails/server.rb

@@ -0,0 +1,30 @@
+# typed: false
+# frozen_string_literal: true
+
+require "json"
+
+running = true
+while running
+  # Read headers until line breaks
+  headers = $stdin.gets("\r\n\r\n")
+
+  # Read the response content based on the length received in the headers
+  request = $stdin.read(headers[/Content-Length: (\d+)/i, 1].to_i)
+
+  json = JSON.parse(request, symbolize_names: true)
+
+  request_method = json.fetch(:method)
+  params = json[:params]
+
+  response_json = nil
+  case request_method
+  when "shutdown"
+    # returning the column names just to illustrate we have access the Rails app
+    response_json = { result: "ok", columns: User.column_names }.to_json
+
+    running = false
+  end
+
+  $stdout.write("Content-Length: #{response_json.length}\r\n\r\n")
+  $stdout.write(response_json)
+end