Fix connection drops

Changelog.md

@@ -3,10 +3,14 @@ This project uses [semantic versioning](http://semver.org/spec/v2.0.0.html). Ref
 *[Semantic Versioning in Practice](https://www.jering.tech/articles/semantic-versioning-in-practice)*
 for an overview of semantic versioning.
 
-## [Unreleased](https://github.com/JeringTech/Javascript.NodeJS/compare/5.2.0...HEAD)
+## [Unreleased](https://github.com/JeringTech/Javascript.NodeJS/compare/5.2.1...HEAD)
 
-## [5.2.0](https://github.com/JeringTech/Javascript.NodeJS/compare/5.1.1...5.2.0) - Dec 4, 2019
+## [5.2.1](https://github.com/JeringTech/Javascript.NodeJS/compare/5.2.0...5.2.1) - Dec 6, 2019
 ### Fixes
+- Improved HTTP connection stability and error logging. ([#61](https://github.com/JeringTech/Javascript.NodeJS/pull/61)).
+
+## [5.2.0](https://github.com/JeringTech/Javascript.NodeJS/compare/5.1.1...5.2.0) - Dec 4, 2019
+### Changes
 - Expanded API. ([#57](https://github.com/JeringTech/Javascript.NodeJS/pull/57)). Added `INodeJSService` members for invocations without return values and 
   atomic/simplified caching-invoking:
   - `Task InvokeFromFileAsync(string modulePath, string exportName = null, object[] args = null, CancellationToken cancellationToken = default);`

src/NodeJS/Javascript/Servers/OutOfProcess/Http/HttpServer.ts

@@ -23,8 +23,19 @@ patchLStat();
 // Set by NodeJSProcessFactory
 let projectDir = process.cwd();
 
+// Create server
+const server = http.createServer(serverOnRequestListener);
+
+// In Node.js v13+ this is the default, however for earlier versions it is 120 seconds.
+server.setTimeout(0);
+
+// Send client error details to client for debugging
+server.on('clientError', serverOnClientError);
+
 // Start server
-const server = http.createServer((req, res) => {
+server.listen(parseInt(args.port), 'localhost', serverOnListeningListener);
+
+function serverOnRequestListener(req, res) {
     let bodyChunks = [];
     req.
         on('data', chunk => bodyChunks.push(chunk)).
@@ -158,12 +169,25 @@ const server = http.createServer((req, res) => {
                 respondWithError(res, error);
             }
         });
-}).listen(parseInt(args.port), 'localhost', function () {
+}
+
+// Send error details to client for debugging - https://nodejs.org/api/http.html#http_event_clienterror
+function serverOnClientError(error: Error, socket: stream.Duplex) {
+    let errorJson = JSON.stringify({
+        errorMessage: error.message,
+        errorStack: error.stack
+    });
+
+    let httpResponseMessage = `HTTP/1.1 500 Internal Server Error\r\nContent-Length: ${Buffer.byteLength(errorJson, 'utf8')}\r\nContent-Type: text/html\r\n\r\n${errorJson}`;
+    socket.end(httpResponseMessage);
+}
+
+function serverOnListeningListener() {
     // Signal to HttpNodeHost which loopback IP address (IPv4 or IPv6) and port it should make its HTTP connections on
     // and that we are ready to process invocations.
     let info = server.address() as AddressInfo;
     console.log(`[Jering.Javascript.NodeJS: Listening on IP - ${info.address} Port - ${info.port}]`);
-});
+}
 
 function getTempIdentifier(invocationRequest: InvocationRequest): string {
     if (invocationRequest.newCacheIdentifier == null) {

test/NodeJS/HttpNodeJSServiceIntegrationTests.cs

@@ -6,7 +6,11 @@
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
+using System.Net;
+using System.Net.Http;
+using System.Net.Sockets;
 using System.Text;
+using System.Text.Json;
 using System.Threading;
 using Xunit;
 using Xunit.Abstractions;
@@ -954,6 +958,31 @@ public static IEnumerable<object[]> AllInvokeMethods_ReceiveAndLogStderrOutput_D
             };
         }
 
+        [Fact]
+        public async void AllInvokeMethods_HandleHttpClientErrorsSuchAsMalformedRequests()
+        {
+            // Arrange
+            HttpNodeJSService testSubject = CreateHttpNodeJSService();
+            await testSubject.InvokeFromStringAsync("module.exports = callback => callback();").ConfigureAwait(false); // Starts the Node.js process
+            Uri dummyEndpoint = testSubject.Endpoint;
+            var dummyJsonService = new JsonService();
+
+            // Act
+            using (var dummyHttpClient = new HttpClient())
+            // Send a request with an invalid HTTP method. NodeJS drops the connection halfway through and fires the clientError event - https://nodejs.org/api/http.html#http_event_clienterror
+            using (var dummyHttpRequestMessage = new HttpRequestMessage(new HttpMethod("INVALID"), dummyEndpoint))
+            using (HttpResponseMessage dummyHttpResponseMessage = await dummyHttpClient.SendAsync(dummyHttpRequestMessage).ConfigureAwait(false))
+            using (Stream dummyStream = await dummyHttpResponseMessage.Content.ReadAsStreamAsync().ConfigureAwait(false))
+            {
+                InvocationError result = await dummyJsonService.DeserializeAsync<InvocationError>(dummyStream).ConfigureAwait(false);
+
+                // Assert
+                Assert.Equal(HttpStatusCode.InternalServerError, dummyHttpResponseMessage.StatusCode);
+                Assert.False(string.IsNullOrWhiteSpace(result.ErrorMessage));
+                Assert.False(string.IsNullOrWhiteSpace(result.ErrorStack));
+            }
+        }
+
         /// <summary>
         /// Specify <paramref name="loggerStringBuilder"/> for access to all logging output.
         /// </summary>