src/main/include/log4cxx/net/telnetappender.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

#ifndef _LOG4CXX_NET_TELNET_APPENDER_H
#define _LOG4CXX_NET_TELNET_APPENDER_H

#include <log4cxx/appenderskeleton.h>
#include <log4cxx/helpers/socket.h>

namespace LOG4CXX_NS
{
namespace helpers
{
class ByteBuffer;
}
namespace net
{

/**
The TelnetAppender writes log messages to
clients that connect to the TCP port.

This allows logging output to be monitored using TCP/IP.
To receive log data, use telnet to connect to the configured port number.

TelnetAppender is most useful as a secondary appender,
especially when monitoring a servlet remotely.

If no layout is provided, the log message only is sent to attached client(s).

See TelnetAppender::setOption() for the available options.

*/
class LOG4CXX_EXPORT TelnetAppender : public AppenderSkeleton
{
	private:
		static const int DEFAULT_PORT;
		static const int MAX_CONNECTIONS;

	public:
		DECLARE_LOG4CXX_OBJECT(TelnetAppender)
		BEGIN_LOG4CXX_CAST_MAP()
		LOG4CXX_CAST_ENTRY(TelnetAppender)
		LOG4CXX_CAST_ENTRY_CHAIN(AppenderSkeleton)
		END_LOG4CXX_CAST_MAP()

		TelnetAppender();
		~TelnetAppender();

		/**
		If no layout is provided, sends only the log message to attached client(s).
		*/
		bool requiresLayout() const override;

		/**
		The current encoding value.

		\sa setOption
		 */
		LogString getEncoding() const;
		/**
		Set the encoding to \c value.

		\sa setOption
		 */
		void setEncoding(const LogString& value);


		/**
		\copybrief AppenderSkeleton::activateOptions()

		Create the socket handler and wait for connections.
		*/
		void activateOptions(helpers::Pool& p) override;


		/**
		\copybrief AppenderSkeleton::setOption()

		Supported options | Supported values | Default value
		-------------- | ---------------- | ---------------
		Port | {int} | 23
		MaxConnections | {int} | 20
		Encoding | C,UTF-8,UTF-16,UTF-16BE,UTF-16LE,646,US-ASCII,ISO646-US,ANSI_X3.4-1968,ISO-8859-1,ISO-LATIN-1 | UTF-8

		\sa AppenderSkeleton::setOption()
		*/
		void setOption(const LogString& option, const LogString& value) override;

		/**
		The TCP <b>Port</b> number on which to accept connections.
		*/
		int getPort() const;

		/**
		Use \c newValue as the TCP port number on which to accept connections.
		*/
		void setPort(int newValue);

		/**
		The number of allowed concurrent connections.

		\sa setOption
		 */
		int getMaxConnections() const;

		/**
		Set the number of allowed concurrent connections to \c newValue.

		\sa setOption
		 */
		void setMaxConnections(int newValue);


		/** Shutdown this appender. */
		void close() override;

	protected:
		/** Send \c event to each connected client.
		*/
		void append(const spi::LoggingEventPtr& event, helpers::Pool& p) override;

	private:
		//   prevent copy and assignment statements
		TelnetAppender(const TelnetAppender&);
		TelnetAppender& operator=(const TelnetAppender&);

		void write(helpers::ByteBuffer&);
		void writeStatus(const helpers::SocketPtr& socket, const LogString& msg, helpers::Pool& p);
		void acceptConnections();

		struct TelnetAppenderPriv;
}; // class TelnetAppender

LOG4CXX_PTR_DEF(TelnetAppender);
} // namespace net
} // namespace log4cxx

#endif // _LOG4CXX_NET_TELNET_APPENDER_H