MsmqAppender.cs :  » Logging-Tools » log4net » SampleAppendersApp » Appender » C# / CSharp Open Source

#region Copyright & License
//
// Copyright 2001-2005 The Apache Software Foundation
//
// 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;
using System.Messaging;

using log4net.Core;

namespace SampleAppendersApp.Appender{
  /// <summary>
  /// Appender writes to a Microsoft Message Queue
  /// </summary>
  /// <remarks>
  /// This appender sends log events via a specified MSMQ queue.
  /// The queue specified in the QueueName (e.g. .\Private$\log-test) must already exist on
  /// the source machine.
  /// The message label and body are rendered using separate layouts.
  /// </remarks>
  public class MsmqAppender : log4net.Appender.AppenderSkeleton
  {
    private MessageQueue m_queue;
    private string m_queueName;
    private log4net.Layout.PatternLayout m_labelLayout;

    public MsmqAppender()
    {
    }

    public string QueueName
    {
      get { return m_queueName; }
      set { m_queueName = value; }
    }

    public log4net.Layout.PatternLayout LabelLayout
    {
      get { return m_labelLayout; }
      set { m_labelLayout = value; }
    }

    override protected void Append(LoggingEvent loggingEvent) 
    {
      if (m_queue == null)
      {
        if (MessageQueue.Exists(m_queueName))
        {
          m_queue = new MessageQueue(m_queueName);
        }
        else
        {
          ErrorHandler.Error("Queue ["+m_queueName+"] not found");
        }
      }

      if (m_queue != null)
      {
        Message message = new Message();

        message.Label = RenderLabel(loggingEvent);

        using(System.IO.MemoryStream stream = new System.IO.MemoryStream())
        {
          System.IO.StreamWriter writer = new System.IO.StreamWriter(stream, new System.Text.UTF8Encoding(false, true));
          base.RenderLoggingEvent(writer, loggingEvent);
          writer.Flush();
          stream.Position = 0;
          message.BodyStream = stream;

          m_queue.Send(message);
        }
      }
    }

    private string RenderLabel(LoggingEvent loggingEvent)
    {
      if (m_labelLayout == null)
      {
        return null;
      }

      System.IO.StringWriter writer = new System.IO.StringWriter();
      m_labelLayout.Format(writer, loggingEvent);

      return writer.ToString();
    }
  }
}