/src/Elmah/Error.cs

#region License, Terms and Author(s)

//

// ELMAH - Error Logging Modules and Handlers for ASP.NET

// Copyright (c) 2004-9 Atif Aziz. All rights reserved.

//

//  Author(s):

//

//      Atif Aziz, http://www.raboof.com

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//    http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

//

#endregion



using System.Collections.Generic;



[assembly: Elmah.Scc("$Id: Error.cs 824 2011-05-03 21:25:06Z azizatif $")]



namespace Elmah

{

    #region Imports



    using System;

    using System.Diagnostics;

    using System.Security;

    using System.Security.Principal;

    using System.Web;

    using System.Xml;

    using Thread = System.Threading.Thread;

    using NameValueCollection = System.Collections.Specialized.NameValueCollection;



    #endregion



    /// <summary>

    /// Represents a logical application error (as opposed to the actual 

    /// exception it may be representing).

    /// </summary>



    public interface IExceptionWithData

    {

        NameValueCollection AdditionalData { get; } 

    }



    [ Serializable ]

    public sealed class Error : ICloneable

    {

        private readonly Exception _exception;

        private string _applicationName;

        private string _hostName;

        private string _typeName;

        private string _source;

        private string _message;

        private string _detail;

        private string _user;

        

        private DateTime _time;

        private int _statusCode;

        private string _webHostHtmlMessage;



        private NameValueCollection _serverVariables;

        private NameValueCollection _queryString;

        private NameValueCollection _form;

        private NameValueCollection _cookies;

        private NameValueCollection _addData;



        /// <summary>

        /// Initializes a new instance of the <see cref="Error"/> class.

        /// </summary>



        public Error() {}



        /// <summary>

        /// Initializes a new instance of the <see cref="Error"/> class

        /// from a given <see cref="Exception"/> instance.

        /// </summary>



        public Error(Exception e) : 

            this(e, null) {}



        /// <summary>

        /// Initializes a new instance of the <see cref="Error"/> class

        /// from a given <see cref="Exception"/> instance and 

        /// <see cref="HttpContext"/> instance representing the HTTP 

        /// context during the exception.

        /// </summary>



        public Error(Exception e, HttpContext context)

        {

            if (e == null)

                throw new ArgumentNullException("e");



            _exception = e;

            Exception baseException = e.GetBaseException();



            //

            // Load the basic information.

            //



            _hostName = Environment.TryGetMachineName(context);

            _typeName = baseException.GetType().FullName;

            _message = baseException.Message;

            _source = baseException.Source;

            _detail = e.ToString();

            _user = Mask.NullString(Thread.CurrentPrincipal.Identity.Name);

            _time = DateTime.Now;



            //

            // If this is an HTTP exception, then get the status code

            // and detailed HTML message provided by the host.

            //



            HttpException httpException = e as HttpException;



            if (httpException != null)

            {

                _statusCode = httpException.GetHttpCode();

                _webHostHtmlMessage = TryGetHtmlErrorMessage(httpException);

            }



            //

            // If the HTTP context is available, then capture the

            // collections that represent the state request as well as

            // the user.

            //



            if (context != null)

            {

                IPrincipal webUser = context.User;

                if (webUser != null 

                    && Mask.NullString(webUser.Identity.Name).Length > 0)

                {

                    _user = webUser.Identity.Name;

                }



                HttpRequest request = context.Request;



                _serverVariables = CopyCollection(request.ServerVariables);

                _queryString = CopyCollection(request.QueryString);

                _form = CopyCollection(request.Form);

                _cookies = CopyCollection(request.Cookies);

            }



            if (e is IExceptionWithData)

            {

                IExceptionWithData exceptionWithData = e as IExceptionWithData;

                _addData = CopyCollection(exceptionWithData.AdditionalData);

            }

        }



        private static string TryGetHtmlErrorMessage(HttpException e)

        {

            Debug.Assert(e != null);



            try

            {

                return e.GetHtmlErrorMessage();

            }

            catch (SecurityException se) 

            {

                // In partial trust environments, HttpException.GetHtmlErrorMessage() 

                // has been known to throw:

                // System.Security.SecurityException: Request for the 

                // permission of type 'System.Web.AspNetHostingPermission' failed.

                // 

                // See issue #179 for more background:

                // http://code.google.com/p/elmah/issues/detail?id=179

                

                Trace.WriteLine(se);

                return null;

            }

        }



        /// <summary>

        /// Gets the <see cref="Exception"/> instance used to initialize this

        /// instance.

        /// </summary>

        /// <remarks>

        /// This is a run-time property only that is not written or read 

        /// during XML serialization via <see cref="ErrorXml.Decode"/> and 

        /// <see cref="ErrorXml.Encode(Error,XmlWriter)"/>.

        /// </remarks>



        public Exception Exception

        {

            get { return _exception; }

        }



        /// <summary>

        /// Gets or sets the name of application in which this error occurred.

        /// </summary>



        public string ApplicationName

        { 

            get { return Mask.NullString(_applicationName); }

            set { _applicationName = value; }

        }



        /// <summary>

        /// Gets or sets name of host machine where this error occurred.

        /// </summary>

        

        public string HostName

        { 

            get { return Mask.NullString(_hostName); }

            set { _hostName = value; }

        }



        /// <summary>

        /// Gets or sets the type, class or category of the error.

        /// </summary>

        

        public string Type

        { 

            get { return Mask.NullString(_typeName); }

            set { _typeName = value; }

        }



        /// <summary>

        /// Gets or sets the source that is the cause of the error.

        /// </summary>

        

        public string Source

        { 

            get { return Mask.NullString(_source); }

            set { _source = value; }

        }



        /// <summary>

        /// Gets or sets a brief text describing the error.

        /// </summary>

        

        public string Message 

        { 

            get { return Mask.NullString(_message); }

            set { _message = value; }

        }



        /// <summary>

        /// Gets or sets a detailed text describing the error, such as a

        /// stack trace.

        /// </summary>



        public string Detail

        { 

            get { return Mask.NullString(_detail); }

            set { _detail = value; }

        }



        /// <summary>

        /// Gets or sets the user logged into the application at the time 

        /// of the error.

        /// </summary>

        

        public string User 

        { 

            get { return Mask.NullString(_user); }

            set { _user = value; }

        }



        /// <summary>

        /// Gets or sets the date and time (in local time) at which the 

        /// error occurred.

        /// </summary>

        

        public DateTime Time 

        { 

            get { return _time; }

            set { _time = value; }

        }



        /// <summary>

        /// Gets or sets the HTTP status code of the output returned to the 

        /// client for the error.

        /// </summary>

        /// <remarks>

        /// For cases where this value cannot always be reliably determined, 

        /// the value may be reported as zero.

        /// </remarks>

        

        public int StatusCode 

        { 

            get { return _statusCode; }

            set { _statusCode = value; }

        }



        /// <summary>

        /// Gets or sets the HTML message generated by the web host (ASP.NET) 

        /// for the given error.

        /// </summary>

        

        public string WebHostHtmlMessage

        {

            get { return Mask.NullString(_webHostHtmlMessage); }

            set { _webHostHtmlMessage = value; }

        }



        /// <summary>

        /// Gets a collection representing the Web server variables

        /// captured as part of diagnostic data for the error.

        /// </summary>

        

        public NameValueCollection ServerVariables 

        { 

            get { return FaultIn(ref _serverVariables);  }

        }



        /// <summary>

        /// Gets a collection representing the Web query string variables

        /// captured as part of diagnostic data for the error.

        /// </summary>

        

        public NameValueCollection QueryString 

        { 

            get { return FaultIn(ref _queryString); } 

        }



        /// <summary>

        /// Gets a collection representing the form variables captured as 

        /// part of diagnostic data for the error.

        /// </summary>

        

        public NameValueCollection Form 

        { 

            get { return FaultIn(ref _form); }

        }



        /// <summary>

        /// Gets a collection representing the client cookies

        /// captured as part of diagnostic data for the error.

        /// </summary>



        public NameValueCollection Cookies 

        {

            get { return FaultIn(ref _cookies); }

        }



        public NameValueCollection AdditionalData   

        {

            get { return FaultIn(ref _addData); }

        }



        /// <summary>

        /// Returns the value of the <see cref="Message"/> property.

        /// </summary>



        public override string ToString()

        {

            return this.Message;

        }



        /// <summary>

        /// Creates a new object that is a copy of the current instance.

        /// </summary>



        object ICloneable.Clone()

        {

            //

            // Make a base shallow copy of all the members.

            //



            Error copy = (Error) MemberwiseClone();



            //

            // Now make a deep copy of items that are mutable.

            //



            copy._serverVariables = CopyCollection(_serverVariables);

            copy._queryString = CopyCollection(_queryString);

            copy._form = CopyCollection(_form);

            copy._cookies = CopyCollection(_cookies);

            copy._addData = CopyCollection(_addData);



            return copy;

        }



        private static NameValueCollection CopyCollection(NameValueCollection collection)

        {

            if (collection == null || collection.Count == 0)

                return null;



            return new NameValueCollection(collection);

        }



        private static NameValueCollection CopyCollection(HttpCookieCollection cookies)

        {

            if (cookies == null || cookies.Count == 0)

                return null;



            NameValueCollection copy = new NameValueCollection(cookies.Count);



            for (int i = 0; i < cookies.Count; i++)

            {

                HttpCookie cookie = cookies[i];



                //

                // NOTE: We drop the Path and Domain properties of the 

                // cookie for sake of simplicity.

                //



                copy.Add(cookie.Name, cookie.Value);

            }



            return copy;

        }



        private static NameValueCollection FaultIn(ref NameValueCollection collection)

        {

            if (collection == null)

                collection = new NameValueCollection();



            return collection;

        }

    }

}