Performance fix

- Usage of resolved loopback IP address instead of 'localhost'

Addresses #1588

src/Microsoft.AspNetCore.NodeServices/Content/Node/entrypoint-http.js

@@ -121,8 +121,8 @@
 	var parsedArgs = ArgsUtil_1.parseArgs(process.argv);
 	var requestedPortOrZero = parsedArgs.port || 0; // 0 means 'let the OS decide'
 	server.listen(requestedPortOrZero, 'localhost', function () {
-	    // Signal to HttpNodeHost which port it should make its HTTP connections on
+	    // Signal to HttpNodeHost which loopback IP address (IPv4 or IPv6) and port it should make its HTTP connections on
-	    console.log('[Microsoft.AspNetCore.NodeServices.HttpNodeHost:Listening on port ' + server.address().port + '\]');
+	    console.log('[Microsoft.AspNetCore.NodeServices.HttpNodeHost:Listening on {' + server.address().address + '} port ' + server.address().port + '\]');
 	    // Signal to the NodeServices base class that we're ready to accept invocations
 	    console.log('[Microsoft.AspNetCore.NodeServices:Listening]');
 	});

src/Microsoft.AspNetCore.NodeServices/HostingModels/HttpNodeInstance.cs

@@ -21,8 +21,8 @@ namespace Microsoft.AspNetCore.NodeServices.HostingModels
     /// <seealso cref="Microsoft.AspNetCore.NodeServices.HostingModels.OutOfProcessNodeInstance" />
     internal class HttpNodeInstance : OutOfProcessNodeInstance
     {
-        private static readonly Regex PortMessageRegex =
+        private static readonly Regex EndpointMessageRegex =
-            new Regex(@"^\[Microsoft.AspNetCore.NodeServices.HttpNodeHost:Listening on port (\d+)\]$");
+            new Regex(@"^\[Microsoft.AspNetCore.NodeServices.HttpNodeHost:Listening on {(.*?)} port (\d+)\]$");
 
         private static readonly JsonSerializerSettings jsonSerializerSettings = new JsonSerializerSettings
         {
@@ -32,7 +32,7 @@ namespace Microsoft.AspNetCore.NodeServices.HostingModels
 
         private readonly HttpClient _client;
         private bool _disposed;
-        private int _portNumber;
+        private string _endpoint;
 
         public HttpNodeInstance(NodeServicesOptions options, int port = 0)
         : base(
@@ -63,7 +63,7 @@ namespace Microsoft.AspNetCore.NodeServices.HostingModels
         {
             var payloadJson = JsonConvert.SerializeObject(invocationInfo, jsonSerializerSettings);
             var payload = new StringContent(payloadJson, Encoding.UTF8, "application/json");
-            var response = await _client.PostAsync("http://localhost:" + _portNumber, payload, cancellationToken);
+            var response = await _client.PostAsync(_endpoint, payload, cancellationToken);
 
             if (!response.IsSuccessStatusCode)
             {
@@ -111,13 +111,19 @@ namespace Microsoft.AspNetCore.NodeServices.HostingModels
 
         protected override void OnOutputDataReceived(string outputData)
         {
-            // Watch for "port selected" messages, and when observed, store the port number
+            // Watch for "port selected" messages, and when observed, 
+            // store the IP (IPv4/IPv6) and port number
             // so we can use it when making HTTP requests. The child process will always send
             // one of these messages before it sends a "ready for connections" message.
-            var match = _portNumber != 0 ? null : PortMessageRegex.Match(outputData);
+            var match = string.IsNullOrEmpty(_endpoint) ? EndpointMessageRegex.Match(outputData) : null;
             if (match != null && match.Success)
             {
-                _portNumber = int.Parse(match.Groups[1].Captures[0].Value);
+                var port = int.Parse(match.Groups[2].Captures[0].Value);
+                var resolvedIpAddress = match.Groups[1].Captures[0].Value;
+
+                //IPv6 must be wrapped with [] brackets
+                resolvedIpAddress = resolvedIpAddress == "::1" ? $"[{resolvedIpAddress}]" : resolvedIpAddress;
+                _endpoint = $"http://{resolvedIpAddress}:{port}";
             }
             else
             {

src/Microsoft.AspNetCore.NodeServices/TypeScript/HttpNodeInstanceEntryPoint.ts

@@ -70,8 +70,8 @@ const server = http.createServer((req, res) => {
 const parsedArgs = parseArgs(process.argv);
 const requestedPortOrZero = parsedArgs.port || 0; // 0 means 'let the OS decide'
 server.listen(requestedPortOrZero, 'localhost', function () {
-    // Signal to HttpNodeHost which port it should make its HTTP connections on
+    // Signal to HttpNodeHost which loopback IP address (IPv4 or IPv6) and port it should make its HTTP connections on
-    console.log('[Microsoft.AspNetCore.NodeServices.HttpNodeHost:Listening on port ' + server.address().port + '\]');
+    console.log('[Microsoft.AspNetCore.NodeServices.HttpNodeHost:Listening on {' + server.address().address + '} port ' + server.address().port + '\]');
 
     // Signal to the NodeServices base class that we're ready to accept invocations
     console.log('[Microsoft.AspNetCore.NodeServices:Listening]');