BeWoPlaner/Service/ServiceBehavior/JsonError/JsonErrorHandler.cs

using BeWo.Data.Access;
using BeWo.Service.Core;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.IO;
using System.Linq;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Json;
using System.ServiceModel.Channels;
using System.ServiceModel.Dispatcher;
using System.Text;
using System.Threading.Tasks;
using System.Xml;

namespace BeWo.Service.ServiceBehavior.JsonError
{
	[DataContract]
	public class JsonError
	{
		[DataMember]
		public string Message { get; set; }

		[DataMember]
		public string StackTrace { get; set; }

		[DataMember]
		public string ExceptionType { get; set; }
	}

	public class JsonErrorHandler : IErrorHandler
	{
		public void ProvideFault(Exception error, MessageVersion version, ref Message fault)
		{
			// Logge in File
			ServiceHelper.JsonErrorLogger.LogError(error);

			// Erstelle eine JSON-Fehlermeldung
			var jsonError = new JsonError
			{
				Message = error.Message,
				ExceptionType = error.GetType().Name
			};

			// Fügt StackTrace hinzu (AppSettings)
			string val = ConfigurationManager.AppSettings["AdminServiceEnableStackTrace"];
			if(bool.TryParse(val, out bool res) && res)
			{
				jsonError.StackTrace = error.StackTrace;
			}

			// Serialisiere das JSON-Objekt
			var serializer = new DataContractJsonSerializer(typeof(JsonError));
			using (var stream = new MemoryStream())
			{
				serializer.WriteObject(stream, jsonError);
				stream.Position = 0;

				using (var reader = new StreamReader(stream))
				{
					string jsonString = reader.ReadToEnd();

					fault = Message.CreateMessage(version, null, new JsonBodyWriter(jsonString));
				}
			}

			// Setze den Content-Type auf application/json
			var webBodyFormat = WebBodyFormatMessageProperty.Name;
			if (!fault.Properties.ContainsKey(webBodyFormat))
			{
				fault.Properties.Add(webBodyFormat, new WebBodyFormatMessageProperty(WebContentFormat.Raw));
			}

			var httpResponse = new HttpResponseMessageProperty
			{
				StatusCode = System.Net.HttpStatusCode.InternalServerError,
				StatusDescription = "Internal Server Error",
			};
			httpResponse.Headers["Content-Type"] = "application/json";
			fault.Properties.Add(HttpResponseMessageProperty.Name, httpResponse);
		}

		public bool HandleError(Exception error)
		{
			// Gib an, ob der Fehler behandelt wurde
			return true;
		}
	}

	public class JsonBodyWriter : BodyWriter
	{
		private readonly string _json;

		public JsonBodyWriter(string json) : base(true)
		{
			_json = json;
		}

		protected override void OnWriteBodyContents(System.Xml.XmlDictionaryWriter writer)
		{
			writer.WriteStartElement("Binary");
			byte[] jsonBytes = Encoding.UTF8.GetBytes(_json);
			writer.WriteBase64(jsonBytes, 0, jsonBytes.Length);
			writer.WriteEndElement();
		}
	}
}