first commit

Packages/com.singularitygroup.hotreload/Runtime/ServerHealthCheck.cs

@@ -0,0 +1,58 @@
+#if ENABLE_MONO && (DEVELOPMENT_BUILD || UNITY_EDITOR)
+using System;
+using System.Threading.Tasks;
+
+namespace SingularityGroup.HotReload {
+    internal class ServerHealthCheck : IServerHealthCheck {
+        private static readonly TimeSpan heartBeatTimeout = TimeSpan.FromMilliseconds(5001);
+        public static readonly ServerHealthCheck I = new ServerHealthCheck();
+
+        private Uri healthCheckEndpoint = null;
+        private Task<bool> healthCheck = null;
+        private DateTime healthOkayAt = DateTime.MinValue;
+
+        public void SetServerInfo(PatchServerInfo serverInfo) {
+            if (serverInfo == null) {
+                Log.Debug("ServerHealthCheck SetServerInfo to null");
+                healthCheckEndpoint = null;
+            } else {
+                var url = RequestHelper.CreateUrl(serverInfo) + "/ping";
+                Log.Debug("ServerHealthCheck SetServerInfo using url {0}", url);
+                healthCheckEndpoint = new Uri(url);
+            }
+            healthCheck = null;
+            healthOkayAt = DateTime.MinValue;
+        }
+
+        public bool IsServerHealthy => DateTime.UtcNow - healthOkayAt < heartBeatTimeout;
+
+        /// Is it confirmed the server has been running before? 
+        public bool WasServerResponding => healthOkayAt != DateTime.MinValue;
+
+        // any thread
+        public async Task CheckHealthAsync() {
+            if (healthCheckEndpoint == null
+                // wait for existing healthcheck to finish
+                || healthCheck?.IsCompleted == false
+            ) {
+                return;
+            }
+            healthCheck = CheckHealthAsync(healthCheckEndpoint);
+            if (await healthCheck) {
+                healthOkayAt = DateTime.UtcNow;
+            }
+        }
+
+        public static async Task<bool> CheckHealthAsync(PatchServerInfo info) {
+            var url = RequestHelper.CreateUrl(info) + "/ping";
+            return await CheckHealthAsync(new Uri(url));
+        }
+        
+        public static async Task<bool> CheckHealthAsync(Uri uri) {
+            var ping = RequestHelper.PingServer(uri);
+            await Task.WhenAny(ping, Task.Delay(heartBeatTimeout));
+            return ping.IsCompleted && ping.Result;
+        }
+    }
+}
+#endif