Include more detail in error messages. Closes #17

Author: Daniel15

src/React/Exceptions/ReactScriptLoadException.cs

@@ -0,0 +1,41 @@
+/*
+ *  Copyright (c) 2014, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant 
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+using System;
+using System.Runtime.Serialization;
+
+namespace React.Exceptions
+{
+	/// <summary>
+	/// Thrown when an error is encountered while loading a JavaScript file.
+	/// </summary>
+	[Serializable]
+	public class ReactScriptLoadException : ReactException
+	{
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ReactScriptLoadException"/> class.
+		/// </summary>
+		/// <param name="message">The message that describes the error.</param>
+		public ReactScriptLoadException(string message) : base(message) { }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ReactScriptLoadException"/> class.
+		/// </summary>
+		/// <param name="message">The error message that explains the reason for the exception.</param>
+		/// <param name="innerException">The exception that is the cause of the current exception, or a null reference (Nothing in Visual Basic) if no inner exception is specified.</param>
+		public ReactScriptLoadException(string message, Exception innerException)
+			: base(message, innerException) { }
+
+		/// <summary>
+		/// Used by deserialization
+		/// </summary>
+		protected ReactScriptLoadException(SerializationInfo info, StreamingContext context)
+			: base(info, context) { }
+	}
+}

src/React/Exceptions/ReactServerRenderingException.cs

@@ -0,0 +1,41 @@
+/*
+ *  Copyright (c) 2014, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant 
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+using System;
+using System.Runtime.Serialization;
+
+namespace React.Exceptions
+{
+	/// <summary>
+	/// Thrown when an error occurs during server rendering of a React component.
+	/// </summary>
+	[Serializable]
+	public class ReactServerRenderingException : ReactException
+	{
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ReactInvalidComponentException"/> class.
+		/// </summary>
+		/// <param name="message">The message that describes the error.</param>
+		public ReactServerRenderingException(string message) : base(message) { }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ReactInvalidComponentException"/> class.
+		/// </summary>
+		/// <param name="message">The error message that explains the reason for the exception.</param>
+		/// <param name="innerException">The exception that is the cause of the current exception, or a null reference (Nothing in Visual Basic) if no inner exception is specified.</param>
+		public ReactServerRenderingException(string message, Exception innerException)
+			: base(message, innerException) { }
+
+		/// <summary>
+		/// Used by deserialization
+		/// </summary>
+		protected ReactServerRenderingException(SerializationInfo info, StreamingContext context)
+			: base(info, context) { }
+	}
+}

src/React/IReactEnvironment.cs

@@ -41,6 +41,15 @@ public interface IReactEnvironment
 		/// <returns>Result of the JavaScript code</returns>
 		T Execute<T>(string code);
 
+		/// <summary>
+		/// Executes the provided JavaScript function, returning a result of the specified type.
+		/// </summary>
+		/// <typeparam name="T">Type to return</typeparam>
+		/// <param name="function">JavaScript function to execute</param>
+		/// <param name="args">Arguments to pass to function</param>
+		/// <returns>Result of the JavaScript code</returns>
+		T Execute<T>(string function, params object[] args);
+
 		/// <summary>
 		/// Attempts to execute the provided JavaScript code using the current engine. If an 
 		/// exception is thrown, retries the execution using a new thread (and hence a new engine)

src/React/JsxTransformer.cs

@@ -98,7 +98,19 @@ public string TransformJsxFile(string filename, bool? useHarmony = null)
 					}
 
 					// 3. Not cached, perform the transformation
-					return TransformJsxWithHeader(contents, hash, useHarmony);
+					try
+					{
+						return TransformJsxWithHeader(contents, hash, useHarmony);
+					}
+					catch (JsxException ex)
+					{
+						// Add the filename to the error message
+						throw new JsxException(string.Format(
+							"In file \"{0}\": {1}",
+							filename,
+							ex.Message
+						));
+					}
 				}
 			);
 		}

src/React/React.csproj

@@ -83,6 +83,8 @@
       <Link>Properties\SharedAssemblyVersionInfo.cs</Link>
     </Compile>
     <Compile Include="AssemblyRegistration.cs" />
+    <Compile Include="Exceptions\ReactScriptLoadException.cs" />
+    <Compile Include="Exceptions\ReactServerRenderingException.cs" />
     <Compile Include="SystemEnvironmentUtils.cs" />
     <Compile Include="Exceptions\JsxUnsupportedEngineException.cs" />
     <Compile Include="Exceptions\ReactConfigurationException.cs" />

src/React/ReactComponent.cs

@@ -9,6 +9,7 @@
 
 using System.Linq;
 using System.Text.RegularExpressions;
+using JavaScriptEngineSwitcher.Core;
 using Newtonsoft.Json;
 using React.Exceptions;
 
@@ -68,15 +69,27 @@ public ReactComponent(IReactEnvironment environment, string componentName, strin
 		public string RenderHtml()
 		{
 			EnsureComponentExists();
-			var html = _environment.Execute<string>(
-				string.Format("React.renderComponentToString({0})", GetComponentInitialiser())
-			);
-			// TODO: Allow changing of the wrapper tag element from a DIV to something else
-			return string.Format(
-				"<div id=\"{0}\">{1}</div>",
-				_containerId,
-				html
-			);
+			try
+			{
+				var html = _environment.Execute<string>(
+					string.Format("React.renderComponentToString({0})", GetComponentInitialiser())
+					);
+				// TODO: Allow changing of the wrapper tag element from a DIV to something else
+				return string.Format(
+					"<div id=\"{0}\">{1}</div>",
+					_containerId,
+					html
+					);
+			}
+			catch (JsRuntimeException ex)
+			{
+				throw new ReactServerRenderingException(string.Format(
+					"Error while rendering \"{0}\" to \"{2}\": {1}",
+					_componentName,
+					ex.Message,
+					_containerId
+				));
+			}
 		}
 
 		/// <summary>

src/React/ReactEnvironment.cs

@@ -14,6 +14,7 @@
 using System.Text;
 using System.Threading;
 using JavaScriptEngineSwitcher.Core;
+using React.Exceptions;
 
 namespace React
 {
@@ -169,7 +170,18 @@ private void EnsureUserScriptsLoaded()
 			foreach (var file in _config.Scripts)
 			{
 				var contents = JsxTransformer.TransformJsxFile(file);
-				Execute(contents);
+				try
+				{
+					Execute(contents);
+				}
+				catch (JsRuntimeException ex)
+				{
+					throw new ReactScriptLoadException(string.Format(
+						"Error while loading \"{0}\": {1}",
+						file,
+						ex.Message
+					));
+				}
 			}
 			Engine.SetVariableValue(USER_SCRIPTS_LOADED_KEY, true);
 		}
@@ -180,7 +192,14 @@ private void EnsureUserScriptsLoaded()
 		/// <param name="code">JavaScript to execute</param>
 		public void Execute(string code)
 		{
-			Engine.Execute(code);
+			try
+			{
+				Engine.Execute(code);
+			}
+			catch (JsRuntimeException ex)
+			{
+				throw WrapJavaScriptRuntimeException(ex);
+			}
 		}
 
 		/// <summary>
@@ -191,7 +210,33 @@ public void Execute(string code)
 		/// <returns>Result of the JavaScript code</returns>
 		public T Execute<T>(string code)
 		{
-			return Engine.Evaluate<T>(code);
+			try
+			{
+				return Engine.Evaluate<T>(code);
+			}
+			catch (JsRuntimeException ex)
+			{
+				throw WrapJavaScriptRuntimeException(ex);
+			}
+		}
+
+		/// <summary>
+		/// Executes the provided JavaScript function, returning a result of the specified type.
+		/// </summary>
+		/// <typeparam name="T">Type to return</typeparam>
+		/// <param name="function">JavaScript function to execute</param>
+		/// <param name="args">Arguments to pass to function</param>
+		/// <returns>Result of the JavaScript code</returns>
+		public T Execute<T>(string function, params object[] args)
+		{
+			try
+			{
+				return Engine.CallFunction<T>(function, args);
+			}
+			catch (JsRuntimeException ex)
+			{
+				throw WrapJavaScriptRuntimeException(ex);
+			}
 		}
 
 		/// <summary>
@@ -201,7 +246,14 @@ public T Execute<T>(string code)
 		/// <returns><c>true</c> if the variable exists; <c>false</c> otherwise</returns>
 		public bool HasVariable(string name)
 		{
-			return Engine.HasVariable(name);
+			try
+			{
+				return Engine.HasVariable(name);
+			}
+			catch (JsRuntimeException ex)
+			{
+				throw WrapJavaScriptRuntimeException(ex);
+			}
 		}
 
 		/// <summary>
@@ -278,7 +330,7 @@ public T ExecuteWithLargerStackIfRequired<T>(string function, params object[] ar
 		{
 			try
 			{
-				return Engine.CallFunction<T>(function, args);
+				return Execute<T>(function, args);
 			}
 			catch (Exception)
 			{
@@ -292,7 +344,7 @@ public T ExecuteWithLargerStackIfRequired<T>(string function, params object[] ar
 					try
 					{
 						// New engine will be created here (as this is a new thread)
-						result = Engine.CallFunction<T>(function, args);
+						result = Execute<T>(function, args);
 					}
 					catch (Exception threadEx)
 					{
@@ -336,5 +388,29 @@ public void Dispose()
 		{
 			_engineFactory.DisposeEngineForCurrentThread();
 		}
+
+		/// <summary>
+		/// Updates the Message of a <see cref="JsRuntimeException"/> to be more useful, containing
+		/// the line and column numbers.
+		/// </summary>
+		/// <param name="ex">Original exception</param>
+		/// <returns>New exception</returns>
+		private JsRuntimeException WrapJavaScriptRuntimeException(JsRuntimeException ex)
+		{
+			return new JsRuntimeException(string.Format(
+				"{0}\r\nLine: {1}\r\nColumn:{2}",
+				ex.Message,
+				ex.LineNumber,
+				ex.ColumnNumber
+			), ex.EngineName, ex.EngineVersion)
+			{
+				ErrorCode = ex.ErrorCode,
+				Category = ex.Category,
+				LineNumber = ex.LineNumber,
+				ColumnNumber = ex.ColumnNumber,
+				SourceFragment = ex.SourceFragment,
+				Source = ex.Source,
+			};
+		}
 	}
 }

src/React/Resources/shims.js

@@ -20,5 +20,9 @@ if (!Object.freeze) {
 }
 
 function ReactNET_transform(input, harmony) {
-	return global.JSXTransformer.transform(input, { harmony: !!harmony }).code;
+	try {
+		return global.JSXTransformer.transform(input, { harmony: !!harmony }).code;
+	} catch (ex) {
+		throw new Error(ex.message + " (at line " + ex.lineNumber + " column " + ex.column + ")");
+	}
 }