LogErrorAttribute.cs

using System;
using System.Collections.Specialized;
using System.Text;
using System.Web;
using System.Web.Mvc;
using log4net;

  /// <summary>
  /// Filter pro logování vyjímek pomocí log4net.
  /// </summary>
  public class LogErrorAttribute : ActionFilterAttribute {

    private readonly ILog _log = log4net.LogManager.GetLogger(typeof(LogErrorAttribute));

    /// <inheritdoc />
    public override void OnActionExecuted(ActionExecutedContext filterContext) {

      if (filterContext.Exception != null) {
        string errorMessage = CreateErrorMessage(filterContext);
        _log.Fatal(errorMessage, filterContext.Exception);
      }

    }

    private static string CreateErrorMessage(ActionExecutedContext filterContext) {
      HttpRequestBase request = filterContext.HttpContext.Request;
      StringBuilder builder = new StringBuilder();

      builder.AppendFormat("Computer: {0}\n", System.Net.Dns.GetHostName());
      builder.AppendFormat("Path: {0}\n", request.Path);
      builder.AppendFormat("Url: {0}\n", request.Url);
      builder.AppendFormat("RawUrl: {0}\n", request.RawUrl);
      builder.AppendFormat("Referer: {0}\n", request.ServerVariables["HTTP_REFERER"]);
      builder.AppendFormat("User: {0}\n", filterContext.HttpContext.User.Identity != null ? filterContext.HttpContext.User.Identity.Name : String.Empty);
      builder.AppendLine("----------------------------------------");
      builder.AppendLine("Headers:");
      AppendCollectionData(request.Headers, builder);
      builder.AppendLine("----------------------------------------");
      builder.AppendLine("Forms:");
      AppendCollectionData(request.Form, builder);
      builder.AppendLine("----------------------------------------");
      builder.AppendLine("Application:");
      AppendApplicationData(filterContext.HttpContext.Application, builder);
      builder.AppendLine("----------------------------------------");
      builder.AppendLine("Cookies:");
      AppendCookies(request.Cookies, builder);
      builder.AppendLine("----------------------------------------");

      return builder.ToString();
    }

    private static void AppendCollectionData(NameValueCollection collection, StringBuilder builder) {
      foreach (string key in collection.AllKeys) {
        builder.AppendFormat("{0} = {1}\n", key, collection[key]);
      }
    }

    private static void AppendApplicationData(HttpApplicationStateBase application, StringBuilder builder) {
      foreach (string key in application.AllKeys) {
        builder.AppendFormat("{0} = {1}\n", key, application[key]);
      }
    }

    private static void AppendCookies(HttpCookieCollection cookies, StringBuilder builder) {
      foreach (string key in cookies.AllKeys) {
        builder.AppendFormat("{0} = {1}\n", key, cookies[key].Value);
      }
    }
}