feat(sse): add new sse_client utils

Author: matthv

packages/forest_admin_datasource_rpc/lib/forest_admin_datasource_rpc/Utils/sse_client.rb

@@ -0,0 +1,66 @@
+require 'openssl'
+require 'json'
+require 'time'
+require 'ld-eventsource'
+
+module ForestAdminDatasourceRpc
+  module Utils
+    class SseClient
+      def initialize(uri, auth_secret)
+        @uri = uri
+        @auth_secret = auth_secret
+        start
+      end
+
+      def start
+        timestamp = Time.now.utc.iso8601
+        signature = generate_signature(timestamp)
+
+        headers = {
+          'Accept' => 'text/event-stream',
+          'X_TIMESTAMP' => timestamp,
+          'X_SIGNATURE' => signature
+        }
+
+        ForestAdminRpcAgent::Facades::Container.logger.log('Debug', "Connecting to SSE at #{@uri}.")
+
+        @client = SSE::Client.new(@uri, headers: headers) do |client|
+          Thread.new do
+            client.on_event do |event|
+              handle_event(event)
+            end
+          rescue StandardError => e
+            puts "[SSE] Connection closed or failed: #{e.class} - #{e.message}"
+            close
+          end
+        end
+      end
+
+      def close
+        return if @closed
+
+        @closed = true
+        @client&.close
+        puts '[SSE] Client closed'
+      end
+
+      private
+
+      def handle_event(event)
+        case event.type.to_s.strip
+        when 'heartbeat'
+          puts '[SSE] Heartbeat'
+        when 'RpcServerStop'
+          puts '[SSE] Server requested stop'
+          close
+        else
+          puts "[SSE] Unknown event: #{event.type} with payload: #{event.data}"
+        end
+      end
+
+      def generate_signature(timestamp)
+        OpenSSL::HMAC.hexdigest('SHA256', @auth_secret, timestamp)
+      end
+    end
+  end
+end