In JavaScriptEngineSwitcher.Node added a handling of errors that occur when switching to multi-process mode of the Jering.Javascript.NodeJS library

Author: Taritsyn

src/JavaScriptEngineSwitcher.Node/JavaScriptEngineSwitcher.Node.csproj

@@ -15,7 +15,7 @@
 This package does not contain the `node.exe`. Therefore, you need to install the Node.js (https://nodejs.org) and add the `node.exe`'s directory to the `Path` environment variable (automatically done by the official installer).</Description>
     <PackageIcon>icon.png</PackageIcon>
     <PackageTags>JavaScriptEngineSwitcher;JavaScript;ECMAScript;Node.js;Jering.Javascript.NodeJS</PackageTags>
-    <PackageReleaseNotes>Jering.Javascript.NodeJS was updated to version 5.4.0.</PackageReleaseNotes>
+    <PackageReleaseNotes>Added a handling of errors that occur when switching to multi-process mode of the Jering.Javascript.NodeJS library.</PackageReleaseNotes>
   </PropertyGroup>
 
   <Import Project="../../build/common.props" />

src/JavaScriptEngineSwitcher.Node/NodeJsEngine.cs

@@ -18,6 +18,7 @@
 using WrapperRuntimeException = JavaScriptEngineSwitcher.Core.JsRuntimeException;
 using WrapperScriptException = JavaScriptEngineSwitcher.Core.JsScriptException;
 using WrapperTimeoutException = JavaScriptEngineSwitcher.Core.JsTimeoutException;
+using WrapperUsageException = JavaScriptEngineSwitcher.Core.JsUsageException;
 
 using JavaScriptEngineSwitcher.Node.Helpers;
 
@@ -286,6 +287,14 @@ private WrapperException WrapInvocationException(InvocationException originalExc
 					wrapperScriptException = new WrapperCompilationException(message, EngineName, _engineVersion,
 						originalException);
 				}
+				else if (type == "UsageError")
+				{
+					wrapperException = new WrapperUsageException(description, EngineName, _engineVersion,
+						originalException);
+					wrapperException.Description = description;
+
+					return wrapperException;
+				}
 				else
 				{
 					var errorLocationItems = new ErrorLocationItem[0];

src/JavaScriptEngineSwitcher.Node/Resources/engine-helpers.js

@@ -1,7 +1,30 @@
-const GENERATED_FUNCTION_CALL_FILE_NAME = "JavaScriptEngineSwitcher.Node.Resources.generated-function-call.js";
+/*jshint esversion: 6*/
+/*globals global, module, require*/
+const GENERATED_FUNCTION_CALL_FILE_NAME = "JavaScriptEngineSwitcher.Node.Resources.generated-function-call.js";
 let vm = require('vm');
 let contexts = new Map();
 
+class UsageError extends Error {
+	constructor(...args) {
+		super(...args);
+		this.name = 'UsageError';
+
+		Error.captureStackTrace(this, UsageError);
+	}
+}
+
+function getContext(engineId) {
+	if (!contexts.has(engineId)) {
+		throw new UsageError("JavaScriptEngineSwitcher.Node module cannot work correctly " +
+			"when the Node JS service is configured to work in the multi-process mode of " +
+			"Jering.Javascript.NodeJS library (https://github.com/JeringTech/Javascript.NodeJS#concurrency), " +
+			"because in this mode it is not possible to store a state of JS engine."
+		);
+	}
+
+	return contexts.get(engineId);
+}
+
 module.exports = {
 	addContext: (callback, engineId, useBuiltinLibrary) => {
 		let sandboxPrototype = useBuiltinLibrary ? global : null;
@@ -19,7 +42,7 @@ module.exports = {
 	},
 
 	evaluate: (callback, engineId, expression, documentName, timeout) => {
-		let context = contexts.get(engineId);
+		let context = getContext(engineId);
 		let options = { filename: documentName };
 		if (timeout > 0) {
 			options.timeout = timeout;
@@ -30,7 +53,7 @@ module.exports = {
 	},
 
 	execute: (callback, engineId, code, documentName, timeout) => {
-		let context = contexts.get(engineId);
+		let context = getContext(engineId);
 		let options = { filename: documentName };
 		if (timeout > 0) {
 			options.timeout = timeout;
@@ -42,7 +65,7 @@ module.exports = {
 	},
 
 	callFunction: (callback, engineId, functionName, args, timeout) => {
-		let context = contexts.get(engineId);
+		let context = getContext(engineId);
 		let result;
 
 		if (timeout <= 0) {
@@ -69,7 +92,7 @@ module.exports = {
 					expression += JSON.stringify(args[argIndex]);
 				}
 
-				expression += ');'
+				expression += ');';
 			}
 			else {
 				expression = `${functionName}();`;
@@ -82,28 +105,28 @@ module.exports = {
 	},
 
 	hasVariable: (callback, engineId, variableName) => {
-		let context = contexts.get(engineId);
+		let context = getContext(engineId);
 		let result = typeof context[variableName] !== 'undefined';
 
 		callback(null, result);
 	},
 
 	getVariableValue: (callback, engineId, variableName) => {
-		let context = contexts.get(engineId);
+		let context = getContext(engineId);
 		let result = context[variableName];
 
 		callback(null, result);
 	},
 
 	setVariableValue: (callback, engineId, variableName, value) => {
-		let context = contexts.get(engineId);
+		let context = getContext(engineId);
 		context[variableName] = value;
 
 		callback(null);
 	},
 
 	removeVariable: (callback, engineId, variableName) => {
-		let context = contexts.get(engineId);
+		let context = getContext(engineId);
 		if (typeof context[variableName] !== 'undefined') {
 			delete context[variableName];
 		}

src/JavaScriptEngineSwitcher.Node/readme.txt

@@ -22,7 +22,8 @@
    =============
    RELEASE NOTES
    =============
-   Jering.Javascript.NodeJS was updated to version 5.4.0.
+   Added a handling of errors that occur when switching to multi-process mode of
+   the Jering.Javascript.NodeJS library.
 
    =============
    DOCUMENTATION