Improve module error handling. Output exception details in debug and …

…error placeholder or nothing in release.

lib/PageRendererBase.js

@@ -38,14 +38,23 @@ var moduleContextHelper = require('./helpers/moduleContextHelper');
  * Creates new instance of base page renderer.
  * @param {ModuleLoader} $moduleLoader Module loader to get modules.
  * @param {Logger} $logger Logger to log messages.
+ * @param {boolean} isRelease Is current application mode release.
  * @constructor
  */
-function PageRendererBase($moduleLoader, $logger) {
+function PageRendererBase($moduleLoader, $logger, isRelease) {
 	this._modulesByNames = $moduleLoader.getModulesByNames();
 	this._logger = $logger;
 	this._initializeTemplates();
+	this._isRelease = Boolean(isRelease);
 }
 
+/**
+ * Is current application mode release.
+ * @type {boolean}
+ * @private
+ */
+PageRendererBase.prototype._isRelease = false;
+
 /**
  * Set of modules by names.
  * @type {Object}

lib/client/ModuleLoader.js

@@ -118,11 +118,20 @@ ModuleLoader.prototype.getModulesByNames = function () {
 			self._templateProvider.registerCompiled(fullName,
 				placeholder.compiledSource);
 
-			module.placeholders[placeholder.name] = placeholder;
+			if (moduleContextHelper.isRootPlaceholder(placeholder.name)) {
+				return;
+			}
 
 			placeholder.getTemplateStream = function (data) {
 				return self._templateProvider.getStream(fullName, data);
 			};
+
+			if (moduleContextHelper.isErrorPlaceholder(placeholder.name)) {
+				module.errorPlaceholder = placeholder;
+			} else {
+				module.placeholders[placeholder.name] = placeholder;
+			}
+
 			self._logger.info(util.format(INFO_PLACEHOLDER_LOADED,
 				placeholder.name,
 				placeholder.moduleName

lib/client/PageRenderer.js

@@ -43,18 +43,20 @@ util.inherits(PageRenderer, PageRendererBase);
 var TRACE_RENDER_PLACEHOLDER = 'Render placeholder "%s" of module "%s"',
 	ID_ATTRIBUTE_NAME = 'id',
 	LOADING_CLASS_NAME = 'loading',
-	BODY_ELEMENT_NAME = 'BODY';
+	BODY_ELEMENT_NAME = 'BODY',
+	ERROR_FORMAT = '%s<br/>%s';
 
 /**
  * Creates instance of client-side page renderer.
  * @param {ModuleLoader} $moduleLoader Module loader to load modules set.
  * @param {Window} $window Browser window to render content.
  * @param {Logger} $logger Logger to log messages.
+ * @param {boolean} isRelease Is application mode release.
  * @constructor
  * @extends PageRendererBase
  */
-function PageRenderer($moduleLoader, $window, $logger) {
-	PageRendererBase.call(this, $moduleLoader, $logger);
+function PageRenderer($moduleLoader, $window, $logger, isRelease) {
+	PageRendererBase.call(this, $moduleLoader, $logger, isRelease);
 	this._window = $window;
 }
 
@@ -126,6 +128,9 @@ PageRenderer.prototype.renderModule =
 				if (moduleContextHelper.isRootPlaceholder(placeholderName)) {
 					return;
 				}
+				if (moduleContextHelper.isErrorPlaceholder(placeholderName)) {
+					return;
+				}
 				// now search root of rendering for each placeholder
 				// of changed module
 				var id = moduleContextHelper.joinModuleNameAndContext(
@@ -215,6 +220,38 @@ PageRenderer.prototype._getIterationAction =
 				currentParameters = parameters[currentItem.moduleName] || {},
 				currentModule = self._modulesByNames[currentItem.moduleName];
 
+			var errorHandler = function (error) {
+				self._logger.error(error);
+				if (!self._isRelease && error instanceof Error) {
+					currentItem.element.empty();
+					currentItem.element.html(util.format(ERROR_FORMAT,
+						error.message, error.stack));
+					currentItem.element.removeClass(LOADING_CLASS_NAME);
+					endCheckAction();
+				} else if (currentModule.errorPlaceholder) {
+					streamHandler(
+						currentModule.errorPlaceholder.getTemplateStream(error));
+				} else {
+					currentItem.element.empty();
+					currentItem.element.removeClass(LOADING_CLASS_NAME);
+				}
+			};
+
+			var streamHandler = function (stream) {
+				currentItem.element.empty();
+				stream.on('data', function (chunk) {
+					currentItem.element.append(chunk);
+				});
+				stream.on('error', function (error) {
+					errorHandler(error);
+					endCheckAction();
+				});
+				stream.on('end', function () {
+					currentItem.element.removeClass(LOADING_CLASS_NAME);
+					checkInner();
+				});
+			};
+
 			// checks if placeholder has something to render inside itself
 			var checkInner = function () {
 				self._placeholderIds
@@ -240,14 +277,12 @@ PageRenderer.prototype._getIterationAction =
 			// module render data handler
 			var dataHandler = function (error, data) {
 				if (error) {
-					self._logger.error(error);
-					currentItem.element.removeClass(LOADING_CLASS_NAME);
-					endCheckAction();
+					errorHandler(error);
 					return;
 				}
 
 				// if module do not wish to render itself again
-				if (!data) {
+				if (!error && !data) {
 					currentItem.element.removeClass(LOADING_CLASS_NAME);
 					checkInner();
 					return;
@@ -256,20 +291,7 @@ PageRenderer.prototype._getIterationAction =
 				self._logger.trace(util.format(TRACE_RENDER_PLACEHOLDER,
 					currentItem.name, currentItem.moduleName));
 
-				currentItem.element.empty();
-				var stream = currentItem.getTemplateStream(data);
-				stream.on('data', function (chunk) {
-					currentItem.element.append(chunk);
-				});
-				stream.on('error', function (error) {
-					self._logger.error(error);
-					currentItem.element.removeClass(LOADING_CLASS_NAME);
-					endCheckAction();
-				});
-				stream.on('end', function () {
-					currentItem.element.removeClass(LOADING_CLASS_NAME);
-					checkInner();
-				});
+				streamHandler(currentItem.getTemplateStream(data));
 			};
 
 			try {
@@ -283,7 +305,7 @@ PageRenderer.prototype._getIterationAction =
 				currentModule.implementation.render(currentItem.name,
 					currentParameters, dataHandler);
 			} catch (e) {
-				self._logger.error(e);
+				errorHandler(e);
 				endCheckAction();
 			}
 		};

lib/helpers/moduleContextHelper.js

@@ -35,7 +35,8 @@ var url = require('url');
 var SLASH_REPLACE_REGEXP = /(^(\/|\\))|((\/|\\)$)/g,
 	MODULE_CONTEXT_PARAMETER_REGEXP = /^\w+_.+$/i,
 	MODULE_CONTEXT_PREFIX_SEPARATOR = '_',
-	ROOT_PLACEHOLDER_NAME = '__index';
+	ROOT_PLACEHOLDER_NAME = '__index',
+	ERROR_PLACEHOLDER_NAME = '__error';
 
 module.exports = {
 
@@ -48,6 +49,15 @@ module.exports = {
 		return placeholderName.toLowerCase() === ROOT_PLACEHOLDER_NAME;
 	},
 
+	/**
+	 * Determines if specified placeholder name is a error placeholder name.
+	 * @param {string} placeholderName Name of placeholder.
+	 * @returns {boolean}
+	 */
+	isErrorPlaceholder: function (placeholderName) {
+		return placeholderName.toLowerCase() === ERROR_PLACEHOLDER_NAME;
+	},
+
 	/**
 	 * Parses query string parameters grouping by modules and globals.
 	 * @param {string} urlText HTTP request URL.

lib/server/ClientBundleBuilder.js

@@ -37,6 +37,7 @@ var path = require('path'),
 	UglifyJS = require('uglify-js'),
 	fs = require('fs'),
 	browserify = require('browserify'),
+	moduleContextHelper = require('../helpers/moduleContextHelper'),
 	packageDescriptionPath = path.join(process.cwd(), 'package.json'),
 	packageDescription;
 
@@ -81,7 +82,7 @@ function ClientBundleBuilder($config, $logger, $templateProvider, $moduleLoader,
 	this._templateProvider = $templateProvider;
 	this._clientTemplateEnginePath = $config.clientTemplateEnginePath;
 	this._moduleLoader = $moduleLoader;
-	this._isRelease = $config.isRelease;
+	this._isRelease = Boolean($config.isRelease);
 	this._serviceLocator = $serviceLocator;
 	if (!fs.existsSync(this._publicPath)) {
 		fs.mkdirSync(this._publicPath);
@@ -232,22 +233,30 @@ ClientBundleBuilder.prototype._generateRequiresForModules = function () {
  * @private
  */
 ClientBundleBuilder.prototype._generatePlaceholders = function () {
-	var placeholders = Object
+	var self = this,
+		results = [];
+	Object
 		.keys(this._templateProvider.compiledSources)
-		.map(function (fullName) {
-			var underscoreIndex = fullName.indexOf('_'),
-				moduleName = fullName.substring(0, underscoreIndex),
-				placeholderName = fullName.substring(underscoreIndex + 1);
-			return {
-				moduleName: moduleName,
-				name: placeholderName,
-				compiledSource: this._templateProvider
+		.forEach(function (fullName) {
+			var moduleAndContext =
+				moduleContextHelper.splitModuleNameAndContext(fullName);
+
+			// we do not need root templates at client-side
+			if (!moduleAndContext ||
+				moduleContextHelper.isRootPlaceholder(moduleAndContext.context)) {
+				return;
+			}
+
+			results.push({
+				moduleName: moduleAndContext.moduleName,
+				name: moduleAndContext.context,
+				compiledSource: self._templateProvider
 					.compiledSources[fullName].toString()
-			};
-		}, this);
+			});
+		});
 
 	return JSON
-		.stringify(placeholders)
+		.stringify(results)
 		.replace(BRACKETS_REGEXP, '');
 };
 

lib/server/ModuleLoader.js

@@ -205,6 +205,11 @@ function loadModule(modulePath, context) {
 				return;
 			}
 
+			if (moduleContextHelper.isErrorPlaceholder(name)) {
+				module.errorPlaceholder = placeholder;
+				return;
+			}
+
 			module.placeholders[name] = placeholder;
 		});
 

lib/server/PageRenderer.js

@@ -53,11 +53,12 @@ util.inherits(PageRenderer, PageRendererBase);
  * @param {ModuleLoader} $moduleLoader Module loader to get modules.
  * @param {ResourceBuilder} $resourceBuilder Resource builder for assets.
  * @param {Logger} $logger Logger to log errors and trace.
+ * @param {boolean} isRelease Is application mode release.
  * @constructor
  * @extends PageRendererBase
  */
-function PageRenderer($moduleLoader, $resourceBuilder, $logger) {
-	PageRendererBase.call(this, $moduleLoader, $logger);
+function PageRenderer($moduleLoader, $resourceBuilder, $logger, isRelease) {
+	PageRendererBase.call(this, $moduleLoader, $logger, isRelease);
 	initializePlaceholders(this);
 	$resourceBuilder.on('built', function () {
 		$logger.info(INFO_READY_TO_HANDLE_REQUESTS);
@@ -83,6 +84,7 @@ PageRenderer.prototype.render =
 			util.format(TRACE_RENDERING_PAGE, pageName));
 		try {
 			context = {
+				isRelease: this._isRelease,
 				parameters: parameters,
 				modulesByNames: this._modulesByNames,
 				placeholderIds: this._placeholderIds,
@@ -94,12 +96,10 @@ PageRenderer.prototype.render =
 
 			renderStream.on('error', function (error) {
 				self._logger.error(error);
-				next(error);
 			});
 
 			transformStream.on('error', function (error) {
 				self._logger.error(error);
-				next(error);
 			});
 
 			renderStream.render();

lib/server/streams/ModuleReadable.js

@@ -38,22 +38,33 @@ var stream = require('stream'),
 
 util.inherits(ModuleReadable, stream.PassThrough);
 
+var ERROR_FORMAT = '%s<br/>%s';
+
 /**
  * Creates new instance of module placeholder rendering stream.
  * @param {Object} module Module which will render placeholder.
  * @param {Object} placeholder Placeholder to render.
  * @param {Object} parameters Set of request parameters.
+ * @param {boolean} isRelease Is application mode release.
  * @constructor
  * @extends PassThrough
  */
-function ModuleReadable(module, placeholder, parameters) {
+function ModuleReadable(module, placeholder, parameters, isRelease) {
 	stream.PassThrough.call(this);
 
 	this._placeholder = placeholder;
 	this._parameters = parameters;
 	this._module = module;
+	this._isRelease = Boolean(isRelease);
 }
 
+/**
+ * Is current application mode release.
+ * @type {boolean}
+ * @private
+ */
+ModuleReadable.prototype._isRelease = false;
+
 /**
  * If module rendering in progress this value is true.
  * @type {boolean}
@@ -100,10 +111,11 @@ ModuleReadable.prototype.render = function () {
 			ownParameters,
 			function (error, content) {
 				if (error) {
-					self.emit('error', error);
+					self._errorHandler(error);
+					return;
 				}
 
-				if (error || !content) {
+				if (!content) {
 					self.end();
 					return;
 				}
@@ -115,7 +127,33 @@ ModuleReadable.prototype.render = function () {
 				contentStream.pipe(self);
 			});
 	} catch (e) {
-		this.emit('error', e);
-		this.end();
+		this._errorHandler(e);
 	}
+};
+
+/**
+ * Handles all errors.
+ * @param {Error} error
+ * @private
+ */
+ModuleReadable.prototype._errorHandler = function (error) {
+	var self = this;
+	setImmediate(function () {
+		self.emit('error', error);
+		// if application in debug mode then render
+		// error text in placeholder
+		if (!self._isRelease && error instanceof Error) {
+			var errorStream = new ContentReadable(
+				util.format(ERROR_FORMAT,
+					error.message, error.stack));
+			errorStream.pipe(self);
+		} else if (self._module.errorPlaceholder) {
+			var errorPlaceholderStream =
+				self._module.errorPlaceholder.getTemplateStream(error);
+			errorPlaceholderStream.pipe(self);
+		} else {
+			self.end();
+		}
+	});
+
 };

lib/server/streams/ParserDuplex.js

@@ -162,7 +162,6 @@ ParserDuplex.prototype._read = function () {
 			}
 			this._replaceStream = this.foundTagIdHandler(tagId);
 			if (this._replaceStream) {
-				this._replaceStream.on('error', this._errorHandler.bind(this));
 				this._replaceStream.on('readable',
 					this._replaceHandler.bind(this));
 				this._replaceStream.on('end',