add support for returning dev errors, improving diagnostics of most common failure cases

src/config/iisnode_schema.xml

@@ -47,5 +47,6 @@ Details at http://learn.iis.net/page.aspx/241/configuration-extensibility/
     <attribute name="maxLogFileSizeInKB" type="uint" defaultValue="128"/>
     <attribute name="loggingEnabled" type="bool" defaultValue="true"/>
     <attribute name="appendToExistingLog" type="bool" defaultValue="false"/>
+    <attribute name="devErrorsEnabled" type="bool" defaultValue="true"/>
   </sectionSchema>
 </configSchema>

src/config/iisnode_schema_x64.xml

@@ -47,5 +47,6 @@ Details at http://learn.iis.net/page.aspx/241/configuration-extensibility/
     <attribute name="maxLogFileSizeInKB" type="uint" defaultValue="128"/>
     <attribute name="loggingEnabled" type="bool" defaultValue="true"/>
     <attribute name="appendToExistingLog" type="bool" defaultValue="false"/>
+    <attribute name="devErrorsEnabled" type="bool" defaultValue="true"/>
   </sectionSchema>
 </configSchema>

src/iisnode/cmoduleconfiguration.cpp

@@ -429,6 +429,7 @@ HRESULT CModuleConfiguration::GetConfig(IHttpContext* context, CModuleConfigurat
 		CheckError(GetDWORD(section, L"maxLogFileSizeInKB", &c->maxLogFileSizeInKB));
 		CheckError(GetBOOL(section, L"loggingEnabled", &c->loggingEnabled));
 		CheckError(GetBOOL(section, L"appendToExistingLog", &c->appendToExistingLog));
+		CheckError(GetBOOL(section, L"devErrorsEnabled", &c->devErrorsEnabled));
 		CheckError(GetString(section, L"logDirectoryNameSuffix", &c->logDirectoryNameSuffix));
 		CheckError(GetBOOL(section, L"debuggingEnabled", &c->debuggingEnabled));
 		CheckError(GetString(section, L"node_env", &c->node_env));
@@ -585,6 +586,11 @@ LPWSTR CModuleConfiguration::GetNodeEnv(IHttpContext* ctx)
 	GETCONFIG(node_env)
 }
 
+BOOL CModuleConfiguration::GetDevErrorsEnabled(IHttpContext* ctx)
+{
+	GETCONFIG(devErrorsEnabled)
+}
+
 HRESULT CModuleConfiguration::GetDebugPortRange(IHttpContext* ctx, DWORD* start, DWORD* end)
 {
 	HRESULT hr;

src/iisnode/cmoduleconfiguration.h

@@ -30,6 +30,7 @@ private:
 	DWORD debugPortStart;
 	DWORD debugPortEnd;
 	LPWSTR node_env;
+	BOOL devErrorsEnabled;
 
 	static IHttpServer* server;
 	static HTTP_MODULE_ID moduleId;
@@ -67,6 +68,7 @@ public:
 	static BOOL GetDebuggingEnabled(IHttpContext* ctx);
 	static HRESULT GetDebugPortRange(IHttpContext* ctx, DWORD* start, DWORD* end);
 	static LPWSTR GetNodeEnv(IHttpContext* ctx);
+	static BOOL GetDevErrorsEnabled(IHttpContext* ctx);
 
 	static HRESULT CreateNodeEnvironment(IHttpContext* ctx, DWORD debugPort, PCH namedPipe, PCH* env);
 

src/iisnode/cnodeapplicationmanager.cpp

@@ -377,7 +377,7 @@ Error:
 	this->GetEventProvider()->Log(
 		L"iisnode failed to unpack debugger files", WINEVENT_LEVEL_ERROR);
 
-	return hr;
+	return IISNODE_ERROR_UNABLE_TO_CREATE_DEBUGGER_FILES;
 }
 
 BOOL CALLBACK CNodeApplicationManager::EnsureDebuggerFile(HMODULE hModule, LPCTSTR lpszType, LPTSTR lpszName, LONG_PTR lParam)

src/iisnode/cnodehttpmodule.cpp

@@ -58,54 +58,7 @@ Error:
 		}
 		CProtocolBridge::SendEmptyResponse(pHttpContext, 501, _T("Not Implemented"), hr);
 	}
-	else if (IISNODE_ERROR_UNRECOGNIZED_DEBUG_COMMAND == hr)
-	{
-		CProtocolBridge::SendSyncResponse(
-			pHttpContext, 
-			200, 
-			"OK", 
-			hr, 
-			TRUE, 
-			"Unrecognized debugging command. Supported commands are ?debug (default), ?brk, and ?kill.");
-	}
-	else if (IISNODE_ERROR_UNABLE_TO_FIND_DEBUGGING_PORT == hr)
-	{
-		CProtocolBridge::SendSyncResponse(
-			pHttpContext, 
-			200, 
-			"OK", 
-			hr, 
-			TRUE, 
-			"The debugger was unable to acquire a TCP port to establish communication with the debugee. "
-			"This may be due to lack of free TCP ports in the range specified in the system.webServer/iisnode/@debuggerPortRange configuration "
-			"section, or due to lack of permissions to create TCP listeners by the identity of the IIS worker process.");
-	}
-	else if (IISNODE_ERROR_UNABLE_TO_CONNECT_TO_DEBUGEE == hr)
-	{
-		CProtocolBridge::SendSyncResponse(
-			pHttpContext, 
-			200, 
-			"OK", 
-			hr, 
-			TRUE, 
-			"The debugger was unable to connect to the the debugee. "
-			"This may be due to the debugee process terminating during startup (e.g. due to an unhandled exception) or "
-			"failing to establish a TCP listener on the debugging port. ");
-	}
-	else if (IISNODE_ERROR_INSPECTOR_NOT_FOUND == hr)
-	{
-		CProtocolBridge::SendSyncResponse(
-			pHttpContext, 
-			200, 
-			"OK", 
-			hr, 
-			TRUE, 
-			"The version of iisnode installed on the server does not support remote debugging. "
-			"To use remote debugging, please update your iisnode installation on the server to one available from "
-			"<a href=""http://github.com/tjanczuk/iisnode/downloads"">http://github.com/tjanczuk/iisnode/downloads</a>. "
-			"We apologize for inconvenience.");
-	}
-	else
+	else if (!CProtocolBridge::SendIisnodeError(pHttpContext, hr))
 	{
 		CProtocolBridge::SendEmptyResponse(pHttpContext, 500, _T("Internal Server Error"), hr);
 	}

src/iisnode/cnodeprocess.cpp

@@ -170,7 +170,7 @@ HRESULT CNodeProcess::Initialize(IHttpContext* context)
 		flags |= CREATE_BREAKAWAY_FROM_JOB;
 	}
 	
-	ErrorIf(FALSE == CreateProcess(
+	if(!CreateProcess(
 			NULL,
 			fullCommandLine,
 			NULL,
@@ -180,8 +180,16 @@ HRESULT CNodeProcess::Initialize(IHttpContext* context)
 			newEnvironment,
 			currentDirectoryA,
 			&this->startupInfo,
-			&processInformation
-		), GetLastError());
+			&processInformation)) 
+	{
+		if (ERROR_FILE_NOT_FOUND == (hr = GetLastError()))
+		{
+			hr = IISNODE_ERROR_UNABLE_TO_START_NODE_EXE;
+		}
+
+		CheckError(hr);
+	}
+		
 
 	// duplicate stdout and stderr handles to allow flushing without regard for whether the node process exited
 	// closing of the original handles will be taken care of by the newly started process
@@ -490,6 +498,7 @@ HRESULT CNodeProcess::CreateStdHandles(IHttpContext* context)
 				this->GetProcessManager()->GetEventProvider()->Log(
 					L"iisnode failed to create directory to store log files for the node.exe process", WINEVENT_LEVEL_ERROR);
 
+				hr = IISNODE_ERROR_UNABLE_TO_CREATE_LOG_FILE;
 				CheckError(hr);
 			}
 		}
@@ -511,15 +520,18 @@ HRESULT CNodeProcess::CreateStdHandles(IHttpContext* context)
 	security.bInheritHandle = TRUE;
 	security.nLength = sizeof SECURITY_ATTRIBUTES;
 	
-	ErrorIf(INVALID_HANDLE_VALUE == (this->startupInfo.hStdOutput = CreateFileW(
+	if (INVALID_HANDLE_VALUE == (this->startupInfo.hStdOutput = CreateFileW(
 		this->loggingEnabled ? logName : L"NUL",
 		GENERIC_READ | GENERIC_WRITE,
 		FILE_SHARE_READ | FILE_SHARE_WRITE,
 		&security,
 		creationDisposition,
 		FILE_ATTRIBUTE_NORMAL | FILE_FLAG_WRITE_THROUGH,
-		NULL)), 
-		GetLastError());
+		NULL)))
+	{
+		hr = this->loggingEnabled ? IISNODE_ERROR_UNABLE_TO_CREATE_LOG_FILE : GetLastError();
+		CheckError(hr);
+	}
 
 	ErrorIf(0 == DuplicateHandle(
 		GetCurrentProcess(),

src/iisnode/cnodeprocessmanager.cpp

@@ -163,7 +163,10 @@ Error:
 		this->GetEventProvider()->Log(
 			L"iisnode failed to initiate processing of a request dequeued from the pending request queue", WINEVENT_LEVEL_ERROR);
 
-		CProtocolBridge::SendEmptyResponse(request, 503, _T("Service Unavailable"), hr);
+		if (!CProtocolBridge::SendIisnodeError(request, hr))
+		{
+			CProtocolBridge::SendEmptyResponse(request, 503, _T("Service Unavailable"), hr);
+		}
 	}
 
 	this->DecRef(); // incremented in CNodeProcessManager::PostDispatchOneRequest

src/iisnode/cprotocolbridge.cpp

@@ -10,10 +10,158 @@ HRESULT CProtocolBridge::PostponeProcessing(CNodeHttpStoredContext* context, DWO
 	return async->SetTimer(context->GetAsyncContext(), &delay);
 }
 
+BOOL CProtocolBridge::SendIisnodeError(IHttpContext* httpCtx, HRESULT hr)
+{
+	if (!CModuleConfiguration::GetDevErrorsEnabled(httpCtx))
+	{
+		return FALSE;
+	}
+
+	switch (hr) {
+
+	default: 
+		return FALSE;
+
+	case IISNODE_ERROR_UNRECOGNIZED_DEBUG_COMMAND:
+		CProtocolBridge::SendSyncResponse(
+			httpCtx, 
+			200, 
+			"OK", 
+			hr, 
+			TRUE, 
+			"Unrecognized debugging command. Supported commands are ?debug (default), ?brk, and ?kill.");
+		break;
+
+	case IISNODE_ERROR_UNABLE_TO_FIND_DEBUGGING_PORT:
+		CProtocolBridge::SendSyncResponse(
+			httpCtx, 
+			200, 
+			"OK", 
+			hr, 
+			TRUE, 
+			"The debugger was unable to acquire a TCP port to establish communication with the debugee. "
+			"This may be due to lack of free TCP ports in the range specified in the <a href=""https://github.com/tjanczuk/iisnode/blob/master/src/samples/configuration/web.config"">"
+			"system.webServer/iisnode/@debuggerPortRange</a> configuration "
+			"section, or due to lack of permissions to create TCP listeners by the identity of the IIS worker process.");
+		break;
+
+	case IISNODE_ERROR_UNABLE_TO_CONNECT_TO_DEBUGEE:
+		CProtocolBridge::SendSyncResponse(
+			httpCtx, 
+			200, 
+			"OK", 
+			hr, 
+			TRUE, 
+			"The debugger was unable to connect to the the debugee. "
+			"This may be due to the debugee process terminating during startup (e.g. due to an unhandled exception) or "
+			"failing to establish a TCP listener on the debugging port. ");
+		break;
+
+	case IISNODE_ERROR_INSPECTOR_NOT_FOUND:
+		CProtocolBridge::SendSyncResponse(
+			httpCtx, 
+			200, 
+			"OK", 
+			hr, 
+			TRUE, 
+			"The version of iisnode installed on the server does not support remote debugging. "
+			"To use remote debugging, please update your iisnode installation on the server to one available from "
+			"<a href=""http://github.com/tjanczuk/iisnode/downloads"">http://github.com/tjanczuk/iisnode/downloads</a>. "
+			"We apologize for inconvenience.");
+		break;
+
+	case IISNODE_ERROR_UNABLE_TO_CREATE_LOG_FILE:
+		CProtocolBridge::SendSyncResponse(
+			httpCtx, 
+			200, 
+			"OK", 
+			hr, 
+			TRUE, 
+			"The iisnode module is unable to create a log file to capture stdout and stderr output from node.exe. "
+			"Please check that the identity of the IIS application pool running the node.js application has read and write access "
+			"permissions to the directory on the server where the node.js application is located. Alternatively you can disable logging "
+			"by setting <a href=""https://github.com/tjanczuk/iisnode/blob/master/src/samples/configuration/web.config"">"
+			"system.webServer/iisnode/@loggingEnabled</a> element of web.config to 'false'.");
+		break;
+
+	case IISNODE_ERROR_UNABLE_TO_CREATE_DEBUGGER_FILES:
+		CProtocolBridge::SendSyncResponse(
+			httpCtx, 
+			200, 
+			"OK", 
+			hr, 
+			TRUE, 
+			"The iisnode module is unable to deploy supporting files necessary to initialize the debugger. "
+			"Please check that the identity of the IIS application pool running the node.js application has read and write access "
+			"permissions to the directory on the server where the node.js application is located.");
+		break;
+
+	case IISNODE_ERROR_UNABLE_TO_START_NODE_EXE:
+		LPCTSTR commandLine = CModuleConfiguration::GetNodeProcessCommandLine(httpCtx);
+		char* errorMessage;
+		if (NULL == (errorMessage = (char*)httpCtx->AllocateRequestMemory(strlen(commandLine) + 512)))
+		{
+			errorMessage = 
+				"The iisnode module is unable to start the node.exe process. Make sure the node.exe executable is available "
+				"at the location specified in the <a href=""https://github.com/tjanczuk/iisnode/blob/master/src/samples/configuration/web.config"">"
+				"system.webServer/iisnode/@nodeProcessCommandLine</a> element of web.config. "
+				"By default node.exe is expected to be installed in %ProgramFiles%\\nodejs folder on x86 systems and "
+				"%ProgramFiles(x86)%\\nodejs folder on x64 systems.";
+		}
+		else
+		{
+			sprintf(errorMessage, 
+				"The iisnode module is unable to start the node.exe process. Make sure the node.exe executable is available "
+				"at the location specified in the <a href=""https://github.com/tjanczuk/iisnode/blob/master/src/samples/configuration/web.config"">"
+				"system.webServer/iisnode/@nodeProcessCommandLine</a> element of web.config. "
+				"The command line iisnode attempted to run was:<br><br>%s", commandLine);
+		}
+
+		CProtocolBridge::SendSyncResponse(
+			httpCtx, 
+			200, 
+			"OK", 
+			hr, 
+			TRUE, 
+			errorMessage);
+		break;
+
+	};
+
+	return TRUE;
+}
+
+BOOL CProtocolBridge::SendIisnodeError(CNodeHttpStoredContext* ctx, HRESULT hr)
+{
+	if (CProtocolBridge::SendIisnodeError(ctx->GetHttpContext(), hr))
+	{
+		ctx->GetNodeApplication()->GetApplicationManager()->GetEventProvider()->Log(
+			L"iisnode request processing failed for reasons recognized by iisnode", WINEVENT_LEVEL_VERBOSE, ctx->GetActivityId());
+
+		if (INVALID_HANDLE_VALUE != ctx->GetPipe())
+		{
+			CloseHandle(ctx->GetPipe());
+			ctx->SetPipe(INVALID_HANDLE_VALUE);
+		}
+
+		CProtocolBridge::FinalizeResponseCore(
+			ctx, 
+			RQ_NOTIFICATION_FINISH_REQUEST, 
+			hr, 
+			ctx->GetNodeApplication()->GetApplicationManager()->GetEventProvider(),
+			L"iisnode posts completion from SendIisnodeError", 
+			WINEVENT_LEVEL_VERBOSE);
+
+		return TRUE;
+	}
+
+	return FALSE;
+}
+
 HRESULT CProtocolBridge::SendEmptyResponse(CNodeHttpStoredContext* context, USHORT status, PCTSTR reason, HRESULT hresult, BOOL disableCache)
 {
 	context->GetNodeApplication()->GetApplicationManager()->GetEventProvider()->Log(
-		L"iisnode request processing failed", WINEVENT_LEVEL_VERBOSE, context->GetActivityId());
+		L"iisnode request processing failed for reasons unrecognized by iisnode", WINEVENT_LEVEL_VERBOSE, context->GetActivityId());
 
 	if (INVALID_HANDLE_VALUE != context->GetPipe())
 	{

src/iisnode/cprotocolbridge.h

@@ -39,6 +39,8 @@ private:
 public:
 
 	static HRESULT InitiateRequest(CNodeHttpStoredContext* context);
+	static BOOL SendIisnodeError(IHttpContext* httpCtx, HRESULT hr);
+	static BOOL SendIisnodeError(CNodeHttpStoredContext* ctx, HRESULT hr);
 	static HRESULT SendEmptyResponse(CNodeHttpStoredContext* context, USHORT status, PCTSTR reason, HRESULT hresult, BOOL disableCache = FALSE);
 	static HRESULT SendSyncResponse(IHttpContext* httpCtx, USHORT status, PCTSTR reason, HRESULT hresult, BOOL disableCache, PCSTR htmlBody);
 	static void SendEmptyResponse(IHttpContext* httpCtx, USHORT status, PCTSTR reason, HRESULT hresult, BOOL disableCache = FALSE);

src/iisnode/errors.h

@@ -5,5 +5,8 @@
 #define IISNODE_ERROR_UNABLE_TO_FIND_DEBUGGING_PORT 1025L
 #define IISNODE_ERROR_UNABLE_TO_CONNECT_TO_DEBUGEE 1026L
 #define IISNODE_ERROR_INSPECTOR_NOT_FOUND 1027L
+#define IISNODE_ERROR_UNABLE_TO_START_NODE_EXE 1028L
+#define IISNODE_ERROR_UNABLE_TO_CREATE_LOG_FILE 1029L
+#define IISNODE_ERROR_UNABLE_TO_CREATE_DEBUGGER_FILES 1030L
 
 #endif

src/iisnode/iisnode.vcxproj

@@ -236,6 +236,7 @@ copy /y $(SolutionDir)\..\config\* $(SolutionDir)\..\..\build\$(Configuration)\$
     <None Include="..\..\test\functional\tests\109_helloworld_debug.js" />
     <None Include="..\..\test\functional\tests\110_log_size_quota.js" />
     <None Include="..\..\test\functional\tests\111_node_env.js" />
+    <None Include="..\..\test\functional\tests\112_dev_errors.js" />
     <None Include="..\..\test\functional\tests\200_samples.bat" />
     <None Include="..\..\test\functional\tests\node_modules\iisnodeassert.js" />
     <None Include="..\..\test\functional\tests\parts\106_autoupdate_first.js" />
@@ -265,6 +266,10 @@ copy /y $(SolutionDir)\..\config\* $(SolutionDir)\..\..\build\$(Configuration)\$
     <None Include="..\..\test\functional\www\110_log_size_quota\web.config" />
     <None Include="..\..\test\functional\www\111_node_env\hello.js" />
     <None Include="..\..\test\functional\www\111_node_env\web.config" />
+    <None Include="..\..\test\functional\www\112_dev_errors\off\hello.js" />
+    <None Include="..\..\test\functional\www\112_dev_errors\off\web.config" />
+    <None Include="..\..\test\functional\www\112_dev_errors\on\hello.js" />
+    <None Include="..\..\test\functional\www\112_dev_errors\on\web.config" />
     <None Include="..\config\iisnode_schema.xml" />
     <None Include="..\config\iisnode_schema_x64.xml" />
     <None Include="..\samples\configuration\hello.js" />

src/iisnode/iisnode.vcxproj.filters

@@ -90,6 +90,15 @@
     <Filter Include="Tests\functional\www\111_node_env">
       <UniqueIdentifier>{b806867c-572b-4438-a6d4-7d24825fc492}</UniqueIdentifier>
     </Filter>
+    <Filter Include="Tests\functional\www\112_dev_errors">
+      <UniqueIdentifier>{2d285139-9862-4a82-be6a-768c87f19c20}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Tests\functional\www\112_dev_errors\on">
+      <UniqueIdentifier>{5df8227d-9e97-4693-a70e-82e98c6bd301}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Tests\functional\www\112_dev_errors\off">
+      <UniqueIdentifier>{4242898e-a656-4ae5-bc35-eb202a42a304}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="main.cpp">
@@ -414,5 +423,20 @@
     <None Include="..\..\test\functional\tests\111_node_env.js">
       <Filter>Tests\functional\tests</Filter>
     </None>
+    <None Include="..\..\test\functional\tests\112_dev_errors.js">
+      <Filter>Tests\functional\tests</Filter>
+    </None>
+    <None Include="..\..\test\functional\www\112_dev_errors\off\hello.js">
+      <Filter>Tests\functional\www\112_dev_errors\off</Filter>
+    </None>
+    <None Include="..\..\test\functional\www\112_dev_errors\off\web.config">
+      <Filter>Tests\functional\www\112_dev_errors\off</Filter>
+    </None>
+    <None Include="..\..\test\functional\www\112_dev_errors\on\hello.js">
+      <Filter>Tests\functional\www\112_dev_errors\on</Filter>
+    </None>
+    <None Include="..\..\test\functional\www\112_dev_errors\on\web.config">
+      <Filter>Tests\functional\www\112_dev_errors\on</Filter>
+    </None>
   </ItemGroup>
 </Project>

src/samples/configuration/readme.htm

@@ -110,6 +110,10 @@ console.log('Application started at location ' + process.env.PORT);</pre>
       number starts; appending may be useful to diagnose unorderly node process terminations or recycling
       
     * logFileFlushInterval - interval in milliseconds for flushing logs to the log files
+
+    * devErrorsEnabled - controls how much information is sent back in the HTTP response to the browser when an error occurrs in iisnode; 
+      when true, error conditions in iisnode result in HTTP 200 response with the body containing error details; when false,
+      iisnode will return generic HTTP 5xx responses
       
     --&gt;
     
@@ -132,6 +136,7 @@ console.log('Application started at location ' + process.env.PORT);</pre>
       debuggerPathSegment="debug"
       maxLogFileSizeInKB="128"
       appendToExistingLog="false"
+      devErrorsEnabled="true"
      /&gt;
 
     &lt;!--     

src/samples/configuration/web.config

@@ -76,6 +76,10 @@
       number starts; appending may be useful to diagnose unorderly node process terminations or recycling
       
     * logFileFlushInterval - interval in milliseconds for flushing logs to the log files
+    
+    * devErrorsEnabled - controls how much information is sent back in the HTTP response to the browser when an error occurrs in iisnode; 
+      when true, error conditions in iisnode result in HTTP 200 response with the body containing error details; when false,
+      iisnode will return generic HTTP 5xx responses
       
     -->
     
@@ -99,6 +103,7 @@
       maxLogFileSizeInKB="128"
       appendToExistingLog="false"
       logFileFlushInterval="5000"
+      devErrorsEnabled="true"
      />
 
     <!--     

test/functional/tests/112_dev_errors.js

@@ -0,0 +1,10 @@
+/*
+When devErrorsEnabled="true", iis failures are reported as HTTP 200, otherwise 5xx
+*/
+
+var iisnodeassert = require("iisnodeassert");
+
+iisnodeassert.sequence([
+    iisnodeassert.get(10000, "/112_dev_errors/on/hello.js", 200),
+    iisnodeassert.get(10000, "/112_dev_errors/off/hello.js", 503)
+]);

test/functional/www/112_dev_errors/off/hello.js

@@ -0,0 +1,6 @@
+var http = require('http');
+
+http.createServer(function (req, res) {
+    res.writeHead(200, {'Content-Type': 'text/html'});
+    res.end('Hello, world!');
+}).listen(process.env.PORT);  

test/functional/www/112_dev_errors/off/web.config

@@ -0,0 +1,10 @@
+<configuration>
+  <system.webServer>
+    <handlers>
+      <add name="iisnode" path="hello.js" verb="*" modules="iisnode" />
+    </handlers>
+
+    <iisnode nodeProcessCommandLine="idontexist.exe" devErrorsEnabled="false" />
+
+  </system.webServer>
+</configuration>

test/functional/www/112_dev_errors/on/hello.js

@@ -0,0 +1,6 @@
+var http = require('http');
+
+http.createServer(function (req, res) {
+    res.writeHead(200, {'Content-Type': 'text/html'});
+    res.end('Hello, world!');
+}).listen(process.env.PORT);  

test/functional/www/112_dev_errors/on/web.config

@@ -0,0 +1,10 @@
+<configuration>
+  <system.webServer>
+    <handlers>
+      <add name="iisnode" path="hello.js" verb="*" modules="iisnode" />
+    </handlers>
+
+    <iisnode nodeProcessCommandLine="idontexist.exe" />
+
+  </system.webServer>
+</configuration>