/**
 *  Copyright (c) 2009, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
 *
 *  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.
 */

package org.apache.synapse.transport.passthru;

import org.apache.axis2.context.MessageContext;
import org.apache.axis2.transport.base.threads.WorkerPool;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.ConnectionClosedException;
import org.apache.http.Header;
import org.apache.http.HttpException;
import org.apache.http.HttpHeaders;
import org.apache.http.HttpRequest;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.HttpVersion;
import org.apache.http.MethodNotSupportedException;
import org.apache.http.message.BasicHttpResponse;
import org.apache.http.nio.ContentDecoder;
import org.apache.http.nio.ContentEncoder;
import org.apache.http.nio.NHttpServerConnection;
import org.apache.http.nio.NHttpServerEventHandler;
import org.apache.http.nio.entity.ContentOutputStream;
import org.apache.http.nio.reactor.IOSession;
import org.apache.http.nio.util.ContentOutputBuffer;
import org.apache.http.nio.util.HeapByteBufferAllocator;
import org.apache.http.nio.util.SimpleOutputBuffer;
import org.apache.http.params.DefaultedHttpParams;
import org.apache.http.protocol.ExecutionContext;
import org.apache.http.protocol.HTTP;
import org.apache.http.protocol.HttpContext;
import org.apache.synapse.commons.CorrelationConstants;
import org.apache.synapse.commons.jmx.ThreadingView;
import org.apache.synapse.commons.logger.ContextAwareLogger;
import org.apache.synapse.commons.transaction.TranscationManger;
import org.apache.synapse.commons.util.MiscellaneousUtil;
import org.apache.synapse.transport.http.conn.LoggingNHttpClientConnection;
import org.apache.synapse.transport.http.conn.LoggingNHttpServerConnection;
import org.apache.synapse.transport.http.conn.Scheme;
import org.apache.synapse.transport.passthru.config.PassThroughConfiguration;
import org.apache.synapse.transport.passthru.config.PassThroughCorrelationConfigDataHolder;
import org.apache.synapse.transport.passthru.config.SourceConfiguration;
import org.apache.synapse.transport.passthru.connections.TargetConnections;
import org.apache.synapse.transport.passthru.jmx.LatencyCollector;
import org.apache.synapse.transport.passthru.jmx.LatencyView;
import org.apache.synapse.transport.passthru.jmx.PassThroughTransportMetricsCollector;

import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.UUID;
import javax.net.ssl.SSLException;
import javax.ws.rs.HttpMethod;

/**
 * This is the class where transport interacts with the client. This class
 * receives events for a particular connection. These events give information
 * about the message and its various states.
 */
public class SourceHandler implements NHttpServerEventHandler {
    private static Log log = LogFactory.getLog(SourceHandler.class);
    private PassThroughConfiguration conf = PassThroughConfiguration.getInstance();

    /** logger for correlation.log */
    private static final Log correlationLog = LogFactory.getLog(PassThroughConstants.CORRELATION_LOGGER);
    private static final Log transportLatencyLog = LogFactory.getLog(PassThroughConstants.TRANSPORT_LATENCY_LOGGER);

    private final SourceConfiguration sourceConfiguration;

    private PassThroughTransportMetricsCollector metrics = null;
    
    private LatencyView latencyView = null;
    
    private LatencyView s2sLatencyView = null;
    private  ThreadingView threadingView;

    private static boolean isMessageSizeValidationEnabled = false;

    private static int validMaxMessageSize = Integer.MAX_VALUE;

    public static final String PROPERTY_FILE = "passthru-http.properties";
    public static final String MESSAGE_SIZE_VALIDATION = "message.size.validation.enabled";
    public static final String VALID_MAX_MESSAGE_SIZE = "valid.max.message.size.in.bytes";

    private List<StreamInterceptor> streamInterceptors;
    private boolean interceptStream;
    private int noOfInterceptors;

    private static final String SSE_TARGET_CONNECTION = "SSE_TARGET_CONNECTION";
    private static final String SSE_TARGET_CONNECTIONS = "SSE_TARGET_CONNECTIONS";

    public SourceHandler(SourceConfiguration sourceConfiguration) {
        this(sourceConfiguration, new ArrayList<StreamInterceptor>());
    }

    public SourceHandler(SourceConfiguration sourceConfiguration, List<StreamInterceptor> streamInterceptors) {
        this.sourceConfiguration = sourceConfiguration;
        this.metrics = sourceConfiguration.getMetrics();
        this.streamInterceptors = streamInterceptors;
        this.interceptStream = !streamInterceptors.isEmpty();
        this.noOfInterceptors = streamInterceptors.size();

        String strNamePostfix = "";
        if (sourceConfiguration.getInDescription() != null &&
            sourceConfiguration.getInDescription().getName() != null) {
            strNamePostfix = "-" + sourceConfiguration.getInDescription().getName();
            Scheme scheme = sourceConfiguration.getScheme();
            boolean enableAdvancedForLatencyView = sourceConfiguration.getBooleanValue(
                    PassThroughConstants.SYNAPSE_PASSTHROUGH_LATENCY_ADVANCE_VIEW, false);
            boolean enableAdvancedForS2SView = sourceConfiguration.getBooleanValue(
                    PassThroughConstants.SYNAPSE_PASSTHROUGH_S2SLATENCY_ADVANCE_VIEW, false);
            this.latencyView = new LatencyView(PassThroughConstants.PASSTHROUGH_LATENCY_VIEW,
                                               scheme.isSSL(), strNamePostfix, enableAdvancedForLatencyView);
            this.s2sLatencyView = new LatencyView(PassThroughConstants.PASSTHROUGH_S2SLATENCY_VIEW, scheme.isSSL(),
                                                  strNamePostfix, enableAdvancedForS2SView);
            this.threadingView = new ThreadingView(PassThroughConstants.PASSTHOUGH_HTTP_SERVER_WORKER, true, 50);
        }

        Properties props = MiscellaneousUtil.loadProperties(PROPERTY_FILE);
        String validationProperty = MiscellaneousUtil.getProperty(props, MESSAGE_SIZE_VALIDATION, "false");
        String validMaxMessageSizeStr = MiscellaneousUtil
                .getProperty(props, VALID_MAX_MESSAGE_SIZE, String.valueOf(Integer.MAX_VALUE));
        isMessageSizeValidationEnabled = Boolean.valueOf(validationProperty);
        try {
            validMaxMessageSize = Integer.valueOf(validMaxMessageSizeStr);
        } catch (NumberFormatException e) {
            log.warn("Invalid max message size configured for property \"valid.max.message.size.in.bytes\", "
                    + "setting the Integer MAX_VALUE as the valid maximum message size", e);
            validMaxMessageSize = Integer.MAX_VALUE;
        }

    }

    public void connected(NHttpServerConnection conn) {
        // we have to have these two operations in order
        sourceConfiguration.getSourceConnections().addConnection(conn);
        SourceContext.create(conn, ProtocolState.REQUEST_READY, sourceConfiguration);
        metrics.connected();
    }

    public void requestReceived(NHttpServerConnection conn) {
        try {
            long requestArrivalTimestamp = 0L;
            if (transportLatencyLog.isDebugEnabled()) {
                requestArrivalTimestamp = System.currentTimeMillis();
            }
            HttpContext httpContext = conn.getContext();
            setCorrelationId(conn);
            if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                SourceContext sourceContext = (SourceContext)
                        conn.getContext().getAttribute(TargetContext.CONNECTION_INFORMATION);
                sourceContext.updateLastStateUpdatedTime();
            }
            httpContext.setAttribute(PassThroughConstants.REQ_ARRIVAL_TIME, System.currentTimeMillis());
            httpContext.setAttribute(PassThroughConstants.REQ_FROM_CLIENT_READ_START_TIME, System.currentTimeMillis());
            if (isMessageSizeValidationEnabled) {
                httpContext.setAttribute(PassThroughConstants.MESSAGE_SIZE_VALIDATION_SUM, 0);
            }
            SourceRequest request = getSourceRequest(conn);
            if (transportLatencyLog.isDebugEnabled()) {
                String method = request == null ? "null" : request.getMethod();
                String uri = request == null ? "null" : request.getUri();
                transportLatencyLog.debug(httpContext.getAttribute(CorrelationConstants.CORRELATION_ID) + "|" +
                        "Received Request from Client at time stamp: " + requestArrivalTimestamp +
                        " and Method/URL: " + method + "/" +uri);
            }
            if (request == null) {
                return;
            }

            String method = request.getRequest() != null ? request.getRequest().getRequestLine().getMethod().toUpperCase() : "";

            if (!request.isEntityEnclosing()) {
                conn.getContext().setAttribute(PassThroughConstants.REQ_FROM_CLIENT_READ_END_TIME, System.currentTimeMillis());
            }
            OutputStream os = getOutputStream(method, request);
            Object correlationId = conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID);
            if (correlationId != null) {
                WorkerPool workerPool = sourceConfiguration.getWorkerPool();
                ServerWorker serverWorker = new ServerWorker(request, sourceConfiguration, os,
                        System.currentTimeMillis(), correlationId.toString());
                conn.getContext().setAttribute(PassThroughConstants.SERVER_WORKER_REFERENCE, serverWorker);
                workerPool.execute(serverWorker);
            } else {
                WorkerPool workerPool = sourceConfiguration.getWorkerPool();
                ServerWorker serverWorker = new ServerWorker(request, sourceConfiguration, os);
                conn.getContext().setAttribute(PassThroughConstants.SERVER_WORKER_REFERENCE, serverWorker);
                workerPool.execute(serverWorker);
            }
            //increasing the input request metric
            metrics.requestReceived();
        } catch (HttpException e) {
            log.error("HttpException occurred when request is processing probably when creating SourceRequest", e);

            informReaderError(conn);

            SourceContext.updateState(conn, ProtocolState.CLOSED);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
        } catch (IOException e) {
            ProtocolState protocolState = SourceContext.getState(conn);
            Map<String, String> logDetails = getLoggingInfo(conn, protocolState);
            log.warn("STATE_DESCRIPTION = IO/Exception occurred when submitting response to request with header "
                    + "Expected: 100-receive, INTERNAL_STATE = " + protocolState + ", DIRECTION = " + logDetails
                    .get("direction") + ", " + "CAUSE_OF_ERROR = " + e.getMessage() + ", HTTP_URL = " + logDetails
                    .get("url") + ", " + "HTTP_METHOD = " + logDetails.get("method") + ", CLIENT_ADDRESS = "
                    + getClientConnectionInfo(conn)
                    + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID)
                    + ", CONNECTION " + conn);
            logIOException(conn, e);

            informReaderError(conn);

            SourceContext.updateState(conn, ProtocolState.CLOSED);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
        }
    }

    public void setCorrelationId(NHttpServerConnection conn) {
        HttpContext httpContext = conn.getContext();
        String correlationHeaderName = PassThroughConfiguration.getInstance().getCorrelationHeaderName();
        Header[] correlationHeader = conn.getHttpRequest().getHeaders(correlationHeaderName);
        String correlationId;
        if (correlationHeader.length != 0) {
            correlationId = correlationHeader[0].getValue();
        } else {
            correlationId = UUID.randomUUID().toString();
            conn.getHttpRequest().setHeader(correlationHeaderName, correlationId);
            httpContext.setAttribute(CorrelationConstants.SYSTEM_GENERATED_CORRELATION_ID, true);
        }
        httpContext.setAttribute(CorrelationConstants.CORRELATION_ID, correlationId);
    }

    public void inputReady(NHttpServerConnection conn,
                           ContentDecoder decoder) {
        try {
            long chunkReadStartTime = 0L;
            if (transportLatencyLog.isDebugEnabled()) {
                chunkReadStartTime = System.currentTimeMillis();
            }
            if (conn.getContext().getAttribute(PassThroughConstants.REQ_FROM_CLIENT_BODY_READ_START_TIME) == null) {
                conn.getContext().setAttribute(PassThroughConstants.REQ_FROM_CLIENT_BODY_READ_START_TIME, chunkReadStartTime);
            }
            ProtocolState protocolState = SourceContext.getState(conn);
            if (protocolState != ProtocolState.REQUEST_HEAD
                    && protocolState != ProtocolState.REQUEST_BODY) {
                // This logic is added specifically here to avoid a race condition that can occur when
                // inputReady is already called prior to suspendInput method is called in TargetHandler.
                SourceContext sourceContext = (SourceContext)
                        conn.getContext().getAttribute(TargetContext.CONNECTION_INFORMATION);
                if (sourceContext != null && sourceContext.isSourceRequestMarkedToBeDiscarded()) {
                    return;
                }
                handleInvalidState(conn, "Request message body data received");
                return;
            }

            SourceContext.updateState(conn, ProtocolState.REQUEST_BODY);

            SourceRequest request = SourceContext.getRequest(conn);

            int readBytes = 0;
            boolean interceptionEnabled = false;
            Boolean[] interceptorResults = new Boolean[noOfInterceptors];
            if (interceptStream) {
                int index = 0;
                for (StreamInterceptor interceptor : streamInterceptors) {
                    interceptorResults[index] = interceptor.interceptSourceRequest((MessageContext) conn.getContext()
                            .getAttribute(PassThroughConstants.REQUEST_MESSAGE_CONTEXT));
                    if (!interceptionEnabled && interceptorResults[index]) {
                        interceptionEnabled = true;
                    }
                    index++;
                }
                if (interceptionEnabled) {
                    ByteBuffer bytesSent = request.copyAndRead(conn, decoder);
                    if (bytesSent != null) {
                        readBytes = bytesSent.remaining();
                        index = 0;
                        for (StreamInterceptor interceptor : streamInterceptors) {
                            if (interceptorResults[index]) {
                                boolean proceed = interceptor.sourceRequest(bytesSent.duplicate().asReadOnlyBuffer(),
                                                                            (MessageContext) conn.getContext()
                                                                                    .getAttribute(
                                                                                            PassThroughConstants.REQUEST_MESSAGE_CONTEXT));
                                if (!proceed) {
                                    log.info("Dropping source connection since request is blocked by : " + interceptor
                                            .getClass().getName());
                                    dropSourceConnection(conn);
                                    conn.getContext().setAttribute(PassThroughConstants.SOURCE_CONNECTION_DROPPED,
                                                                   true);
                                    request.getPipe().forceProducerComplete(decoder);
                                    break;
                                }
                            }
                            index++;
                        }
                    }
                } else {
                    readBytes = request.read(conn, decoder);
                }
            } else {
                readBytes = request.read(conn, decoder);
            }

            long chunkReadEndTime = 0L;
            if (transportLatencyLog.isTraceEnabled()) {
                chunkReadEndTime = System.currentTimeMillis();
                String method = conn.getHttpRequest().getRequestLine().getMethod().toUpperCase();
                String uri = conn.getHttpRequest().getRequestLine().getUri();
                transportLatencyLog.trace(conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID) + "|" +
                        "Request chunk from Client with Method/URL: " + method + "/" + uri +
                        " reading completed at time stamp: " + System.currentTimeMillis() +
                        " and the time taken to read the chunk: " + (chunkReadEndTime - chunkReadStartTime));
            }
            if (decoder.isCompleted()) {
                if (transportLatencyLog.isDebugEnabled()) {
                    chunkReadEndTime = System.currentTimeMillis();
                    String method = conn.getHttpRequest().getRequestLine().getMethod().toUpperCase();
                    String uri = conn.getHttpRequest().getRequestLine().getUri();
                    long requestReadTime = chunkReadEndTime - (long) conn.getContext()
                            .getAttribute(PassThroughConstants.REQ_FROM_CLIENT_BODY_READ_START_TIME);
                    transportLatencyLog.debug(conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID) + "|" +
                            "Request from Client with Method/URL: " + method + "/" + uri +
                            " has been completely read at time stamp: " + chunkReadEndTime +
                            " and the time taken to read the request: " + requestReadTime);
                }
                conn.getContext().removeAttribute(PassThroughConstants.REQ_FROM_CLIENT_BODY_READ_START_TIME);
            }

            if (isMessageSizeValidationEnabled) {
                HttpContext httpContext = conn.getContext();
                //this is introduced as some transports which extends passthrough source handler which have overloaded
                //method requestReceived() Eg:- inbound http/https
                if (httpContext.getAttribute(PassThroughConstants.MESSAGE_SIZE_VALIDATION_SUM) == null) {
                    httpContext.setAttribute(PassThroughConstants.MESSAGE_SIZE_VALIDATION_SUM, 0);
                }
                int messageSizeSum = (int) httpContext.getAttribute(PassThroughConstants.MESSAGE_SIZE_VALIDATION_SUM);

                messageSizeSum += readBytes;

                if (messageSizeSum > validMaxMessageSize) {
                    log.warn("Payload exceeds valid payload size range, hence discontinuing chunk stream at "
                            + messageSizeSum + " bytes to prevent OOM.");
                    dropSourceConnection(conn);
                    metrics.exceptionOccured();
                    conn.getContext().setAttribute(PassThroughConstants.SOURCE_CONNECTION_DROPPED, true);
                    //stopped http chunk stream from here and mark producer complete
                    request.getPipe().forceProducerComplete(decoder);
                }
                httpContext.setAttribute(PassThroughConstants.MESSAGE_SIZE_VALIDATION_SUM, messageSizeSum);
            }

            if (readBytes > 0) {
                metrics.incrementBytesReceived(readBytes);
            }
        } catch (IOException e) {
            ProtocolState protocolState = SourceContext.getState(conn);
            Map<String, String> logDetails = getLoggingInfo(conn, protocolState);
            log.warn("STATE_DESCRIPTION = IO/Exception when reading bytes of request body from the underlying stream, "
                    + "INTERNAL_STATE" + " = " + protocolState + ", DIRECTION = " + logDetails.get("direction") + ", "
                    + "CAUSE_OF_ERROR = " + e.getMessage() + ", HTTP_URL = " + logDetails.get("url") + ", "
                    + "HTTP_METHOD = " + logDetails.get("method") + ", CLIENT_ADDRESS = " + getClientConnectionInfo(
                    conn) + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID)
                    + ", CONNECTION = " + conn);

            logIOException(conn, e);

            informReaderError(conn);
            //decrementing the request metric
            metrics.exceptionOccured();

            SourceContext.updateState(conn, ProtocolState.CLOSED);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
        }
    }

    /**
     * Closes the source side HTTP connection.
     *
     * @param conn HTTP server connection reference
     */
    private void dropSourceConnection(NHttpServerConnection conn) {
        try {
            HttpContext httpContext = conn.getContext();

            HttpResponse response = new BasicHttpResponse(HttpVersion.HTTP_1_1, HttpStatus.SC_REQUEST_TOO_LONG,
                    "Payload Too Large");
            response.setParams(new DefaultedHttpParams(sourceConfiguration.getHttpParams(), response.getParams()));
            response.addHeader(HTTP.CONN_DIRECTIVE, HTTP.CONN_CLOSE);

            httpContext.setAttribute(ExecutionContext.HTTP_CONNECTION, conn);
            httpContext.setAttribute(ExecutionContext.HTTP_REQUEST, null);
            httpContext.setAttribute(ExecutionContext.HTTP_RESPONSE, response);

            sourceConfiguration.getHttpProcessor().process(response, httpContext);

            conn.submitResponse(response);
            SourceContext.updateState(conn, ProtocolState.CLOSED);
            conn.close();
        } catch (Exception ex) {
            log.error(ex.getMessage(), ex);
            SourceContext.updateState(conn, ProtocolState.CLOSED);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
        }
    }

    public void responseReady(NHttpServerConnection conn) {
        try {
            ProtocolState protocolState = SourceContext.getState(conn);
            SourceContext sourceContext = (SourceContext)
                    conn.getContext().getAttribute(TargetContext.CONNECTION_INFORMATION);

            if (protocolState.compareTo(ProtocolState.CLOSING) >= 0) {
                informWriterError(conn);
                return;
            }
            if (sourceContext != null && sourceContext.isSourceRequestMarkedToBeDiscarded() && protocolState != ProtocolState.REQUEST_READY) {
                SourceContext.updateState(conn, ProtocolState.REQUEST_DONE);
            } else {
                if (protocolState.compareTo(ProtocolState.REQUEST_DONE) < 0) {
                    return;
                }
                if (protocolState != ProtocolState.REQUEST_DONE) {
                    handleInvalidState(conn, "Writing a response");
                    return;
                }
            }

            // because the duplex nature of http core we can reach hear without a actual response
            SourceResponse response = SourceContext.getResponse(conn);
            SourceRequest request = SourceContext.getRequest(conn);
            if (response != null) {
                if (SourceContext.get(conn).isShutDown()) {
                    response.setKeepAlive(false);
                }
                // Handle Http ETag
                String ifNoneMatchHeader =
                        SourceContext.getRequest(conn).getHeaders().get(HttpHeaders.IF_NONE_MATCH);
                if (ifNoneMatchHeader != null) {
                    String eTagHeader = response.getHeader(HttpHeaders.ETAG);
                    if (eTagHeader != null) {
                        for (String hashValue : ifNoneMatchHeader.split(",")) {
                            if (hashValue.trim().equals(eTagHeader)) {
                                response.setStatus(HttpStatus.SC_NOT_MODIFIED);
                                break;
                            }
                        }
                    }
                }

                response.start(conn);
                HttpContext context = conn.getContext();
                if (transportLatencyLog.isDebugEnabled()) {
                    String method = request == null ? "null" : request.getMethod();
                    String uri = request == null ? "null" : request.getUri();
                    transportLatencyLog.debug(context.getAttribute(CorrelationConstants.CORRELATION_ID) + "|" +
                            "Response writing started at timestamp: " + System.currentTimeMillis() +
                            " and Method/URL: " + method + "/" +uri);
                }
                context.setAttribute(PassThroughConstants.RES_TO_CLIENT_WRITE_START_TIME,
                        System.currentTimeMillis());
                metrics.incrementMessagesSent();
                if (!response.hasEntity()) {
                   // Update stats as outputReady will not be triggered for no entity responses
                    context = conn.getContext();
                    if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                        logCorrelationRoundTrip(context,request);
                    }
                    updateMetricsView(context);
                }
            }
        } catch (IOException e) {
            logIOException(conn, e);

            informWriterError(conn);

            SourceContext.updateState(conn, ProtocolState.CLOSING);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
        } catch (HttpException e) {
            log.error(e.getMessage(), e);

            informWriterError(conn);

            SourceContext.updateState(conn, ProtocolState.CLOSING);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
        }
    }

    public void outputReady(NHttpServerConnection conn,
                            ContentEncoder encoder) {
        try {
            long chunkWriteStartTime = 0L;
            if (transportLatencyLog.isDebugEnabled()) {
                chunkWriteStartTime = System.currentTimeMillis();
            }
            if (conn.getContext().getAttribute(PassThroughConstants.RES_TO_CLIENT_BODY_WRITE_START_TIME) == null) {
                conn.getContext().setAttribute(PassThroughConstants.RES_TO_CLIENT_BODY_WRITE_START_TIME, chunkWriteStartTime);
            }
            ProtocolState protocolState = SourceContext.getState(conn);
            
            //special case to handle WSDLs
            if(protocolState == ProtocolState.WSDL_RESPONSE_DONE){
                //decrement request count for wsdl responses
                metrics.requestServed();
                // we need to shut down if the shutdown flag is set
                HttpContext context = conn.getContext();
                ContentOutputBuffer outBuf = (ContentOutputBuffer) context.getAttribute(
                         "synapse.response-source-buffer");
                int bytesWritten = outBuf.produceContent(encoder);
                  if (metrics != null && bytesWritten > 0) {
                      metrics.incrementBytesSent(bytesWritten);
                  }
                
                  conn.requestInput();
                  if(outBuf instanceof SimpleOutputBuffer && !((SimpleOutputBuffer)outBuf).hasData()){
                      sourceConfiguration.getSourceConnections().releaseConnection(conn);
                  }
                  endTransaction(conn);
                return;
            }
            
                        
            if (protocolState != ProtocolState.RESPONSE_HEAD
                    && protocolState != ProtocolState.RESPONSE_BODY) {
                log.warn("Illegal incoming connection state: "
                        + protocolState + " . Possibly two send backs " +
                        "are happening for the same request");

                handleInvalidState(conn, "Trying to write response body");
                endTransaction(conn);
                return;
            }
            SourceRequest request = SourceContext.getRequest(conn);
            SourceContext.updateState(conn, ProtocolState.RESPONSE_BODY);

            SourceResponse response = SourceContext.getResponse(conn);

            int bytesSent = -1;
            boolean interceptionEnabled = false;
            Boolean[] interceptorResults = new Boolean[noOfInterceptors];
            if (interceptStream) {
                int index = 0;
                for (StreamInterceptor interceptor : streamInterceptors) {
                    interceptorResults[index] = interceptor.interceptSourceResponse((MessageContext) conn.getContext()
                            .getAttribute(PassThroughConstants.RESPONSE_MESSAGE_CONTEXT));
                    if (!interceptionEnabled && interceptorResults[index]) {
                        interceptionEnabled = true;
                    }
                    index++;
                }
                if (interceptionEnabled) {
                    ByteBuffer bytesWritten = response.copyAndWrite(conn, encoder);
                    if (bytesWritten != null) {
                        bytesSent = bytesWritten.remaining();
                        index = 0;
                        for (StreamInterceptor interceptor : streamInterceptors) {
                            if (interceptorResults[index]) {
                                interceptor.sourceResponse(bytesWritten.duplicate().asReadOnlyBuffer(),
                                                           (MessageContext) conn.getContext().getAttribute(
                                                                   PassThroughConstants.RESPONSE_MESSAGE_CONTEXT));
                            }
                            index++;
                        }
                    }
                } else {
                    bytesSent = response.write(conn, encoder);
                }
            } else {
                bytesSent = response.write(conn, encoder);
            }
            long chunkWriteEndTime = 0L;
            if (transportLatencyLog.isTraceEnabled()) {
                chunkWriteEndTime = System.currentTimeMillis();
                String method = request == null ? "null" : request.getMethod();
                String uri = request == null ? "null" : request.getUri();
                transportLatencyLog.trace(conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID) + "|" +
                        "Response chunk to Client with Method/URL: " + method + "/" + uri +
                        " writing completed at timestamp: " + chunkWriteEndTime +
                        " and the time taken to write chunk:" + (chunkWriteEndTime - chunkWriteStartTime));
            }
            if (encoder.isCompleted()) {
                HttpContext context = conn.getContext();
                chunkWriteEndTime = System.currentTimeMillis();
                if (transportLatencyLog.isDebugEnabled()) {
                    String method = request == null ? "null" : request.getMethod();
                    String uri = request == null ? "null" : request.getUri();
                    long responseWriteTime = chunkWriteEndTime - (long) context.getAttribute(PassThroughConstants.RES_TO_CLIENT_BODY_WRITE_START_TIME);
                    transportLatencyLog.debug(context.getAttribute(CorrelationConstants.CORRELATION_ID) + "|" +
                            "Response writing completed at timestamp: " + chunkWriteEndTime + " and Method/URL: " +
                            "Response with Method/URL: " + method + "/" + uri +
                            " has been completely written at timestamp: " + chunkWriteEndTime +
                            " and the time taken to write response:" + responseWriteTime);
                }
                context.removeAttribute(PassThroughConstants.RES_TO_CLIENT_BODY_WRITE_START_TIME);
                context.setAttribute(PassThroughConstants.RES_TO_CLIENT_WRITE_END_TIME, chunkWriteEndTime);
                context.setAttribute(PassThroughConstants.RES_DEPARTURE_TIME, chunkWriteEndTime);

                if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                    logCorrelationRoundTrip(context, request);
                }
                updateMetricsView(context);
            }
            endTransaction(conn);
            metrics.incrementBytesSent(bytesSent);
        } catch (IOException e) {
            logIOException(conn, e);

            informWriterError(conn);

            SourceContext.updateState(conn, ProtocolState.CLOSING);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
        }
    }

    private void logCorrelationRoundTrip(HttpContext context, SourceRequest request) {

        long startTime = (long) context.getAttribute(PassThroughConstants.REQ_ARRIVAL_TIME);
        ContextAwareLogger.getLogger(context, correlationLog, false)
                .info((System.currentTimeMillis() - startTime) + "|HTTP|" + context.getAttribute("http.connection")
                        + "|" + request.getMethod() + "|" + request.getUri() + "|ROUND-TRIP LATENCY ");
    }

    public void logIOException(NHttpServerConnection conn, IOException e) {
        // this check feels like crazy! But weird things happened, when load testing.
        if (e == null) {
            return;
        }
        if (e instanceof ConnectionClosedException || (e.getMessage() != null && (
                e.getMessage().toLowerCase().contains("connection reset by peer") ||
                e.getMessage().toLowerCase().contains("forcibly closed")))) {
            if (log.isDebugEnabled()) {
                log.debug(conn + ": I/O error (Probably the keepalive connection "
                        + "was closed):" + e.getMessage()
                        + "CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID));
            }
        } else if (e instanceof SSLException) {
            log.warn("I/O error: " + e.getMessage());
        }
        else if (e.getMessage() != null) {
            String msg = e.getMessage().toLowerCase();
            if (msg.indexOf("broken") != -1) {
                log.warn("I/O error (Probably the connection "
                        + "was closed by the remote party):" + e.getMessage()
                        + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID));
            } else {
                log.error("I/O error: " + e.getMessage() + ", CORRELATION_ID = "
                        + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID), e);
            }

            metrics.incrementFaultsReceiving();
        } else {
            log.error("Unexpected I/O error: " + e.getClass().getName()
                    + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID), e);

            metrics.incrementFaultsReceiving();
        }
    }

    public void timeout(NHttpServerConnection conn) {
        boolean isTimeoutOccurred = false;
        ProtocolState state = SourceContext.getState(conn);
        Map<String, String> logDetails = getLoggingInfo(conn, state);
        Object serverWorker = conn.getContext().getAttribute(
                PassThroughConstants.SERVER_WORKER_REFERENCE);
        Object messageDiscardWorker = conn.getContext().getAttribute(
                PassThroughConstants.MESSAGE_DISCARD_WORKER_REFERENCE);
        if (state == ProtocolState.REQUEST_READY || state == ProtocolState.RESPONSE_DONE) {
            if (log.isDebugEnabled()) {
                log.debug(conn + ": Keep-Alive connection was time out: ");
            }
        } else if (state == ProtocolState.REQUEST_BODY || state == ProtocolState.REQUEST_HEAD) {
            metrics.incrementTimeoutsReceiving();
            metrics.timeoutOccured();
            informReaderError(conn);
            isTimeoutOccurred = true;

            String logMessage = "STATE_DESCRIPTION = Socket Timeout occurred after reading the request "
                    + "headers but Server is "
                    + "still reading the request body, INTERNAL_STATE = " + state + ", DIRECTION = "
                    + logDetails.get("direction") + ", "
                    + "CAUSE_OF_ERROR = Connection between the client and the EI timeouts, HTTP_URL = "
                    + logDetails.get("url") + ", " + "HTTP_METHOD = " + logDetails.get("method") + ", SOCKET_TIMEOUT = "
                    + conn.getSocketTimeout() + ", CLIENT_ADDRESS = " + getClientConnectionInfo(conn)
                    + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID)
                    + ", CONNECTION = " + conn;
            if (isPrimaryWorkerPoolExhausted(serverWorker)) {
                log.warn(logMessage + ", Could not get a  PassThroughMessageProcessor thread to process the "
                        + "request message. The primary worker pool is exhausted.");
            } else {
                log.warn(logMessage + secondaryWorkerPoolExhaustedErrorMessage(messageDiscardWorker));
            }
            if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                logHttpRequestErrorInCorrelationLog(conn, "TIMEOUT in " + state.name());
            }
        } else if (state == ProtocolState.RESPONSE_BODY || state == ProtocolState.RESPONSE_HEAD) {
            informWriterError(conn);
            isTimeoutOccurred = true;
            metrics.timeoutOccured();
            String logMessage = "STATE_DESCRIPTION = Socket Timeout occurred after server writing the response"
                    + " headers to the "
                    + "client" + "but Server is still writing the response body, INTERNAL_STATE = " + state
                    + ", DIRECTION = " + logDetails.get("direction") + ", "
                    + "CAUSE_OF_ERROR = Connection between the client and the EI timeouts, HTTP_URL = "
                    + logDetails.get("url") + ", " + "HTTP_METHOD = " + logDetails.get("method") + ", SOCKET_TIMEOUT = "
                    + conn.getSocketTimeout() + ", CLIENT_ADDRESS = " + getClientConnectionInfo(conn)
                    + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID)
                    + ", CONNECTION = " + conn;

            if (isPrimaryWorkerPoolExhausted(serverWorker)) {
                log.warn(logMessage + ", Could not get a  PassThroughMessageProcessor thread to process the "
                        + "request message. The primary worker pool is exhausted.");
            } else {
                log.warn(logMessage + secondaryWorkerPoolExhaustedErrorMessage(messageDiscardWorker));
            }
            if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                logHttpRequestErrorInCorrelationLog(conn, "TIMEOUT in " + state.name());
            }
        } else if (state == ProtocolState.REQUEST_DONE) {
            informWriterError(conn);
            isTimeoutOccurred = true;
            metrics.timeoutOccured();
            String logMessage = "STATE_DESCRIPTION = Socket Timeout occurred after accepting the request"
                    + " headers and the request "
                    + "body, INTERNAL_STATE = "
                    + state + ", DIRECTION = " + logDetails.get("direction") + ", "
                    + "CAUSE_OF_ERROR = Connection between the client and the WSO2 server timeouts, HTTP_URL = "
                    + logDetails.get("url") + ", " + "HTTP_METHOD = " + logDetails.get("method")
                    + ", SOCKET_TIMEOUT = " + conn.getSocketTimeout() + ", CLIENT_ADDRESS = "
                    + getClientConnectionInfo(conn)
                    + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID)
                    + ", CONNECTION = " + conn;
            if (isPrimaryWorkerPoolExhausted(serverWorker)) {
                log.warn(logMessage + ", Could not get a  PassThroughMessageProcessor thread to process the "
                        + "request message. The primary worker pool is exhausted.");
            } else {
                log.warn(logMessage + secondaryWorkerPoolExhaustedErrorMessage(messageDiscardWorker));
            }
            if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                logHttpRequestErrorInCorrelationLog(conn, "TIMEOUT in " + state.name());
            }
        }

        SourceContext.updateState(conn, ProtocolState.CLOSED);

        if (conf.isTLSGracefulConnectionTerminationEnabled()) {
            sourceConfiguration.getSourceConnections().closeConnection(conn, true);
        } else {
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
        }

        if (isTimeoutOccurred) {
            rollbackTransaction(conn);
        }
    }

    private String secondaryWorkerPoolExhaustedErrorMessage(Object messageDiscardWorker) {
        String workerPoolExhaustedMessage = "";
        if (messageDiscardWorker == null) {
            return workerPoolExhaustedMessage;
        }
        MessageDiscardWorker msgDiscardWorker = (MessageDiscardWorker) messageDiscardWorker;
        if (WorkerState.CREATED == msgDiscardWorker.getWorkerState()) {
            workerPoolExhaustedMessage = ", Could not get a secondary worker thread to discard the request content. "
                    + "The secondary worker pool is exhausted.";
            return workerPoolExhaustedMessage;
        } else if (WorkerState.RUNNING == msgDiscardWorker.getWorkerState()) {
            workerPoolExhaustedMessage = ", The secondary worker thread which was discarding the request content"
                    + " has been released.";
            return workerPoolExhaustedMessage;
        }
        return workerPoolExhaustedMessage;
    }

    private boolean isPrimaryWorkerPoolExhausted(Object serverWorker) {
        if (serverWorker == null) {
            return false;
        }
        return WorkerState.RUNNING != ((ServerWorker)serverWorker).getWorkerState();
    }

    public void closed(NHttpServerConnection conn) {
        ProtocolState state = SourceContext.getState(conn);
        Map<String, String> logDetails = getLoggingInfo(conn, state);
        boolean isFault = false;
        if (state == ProtocolState.REQUEST_READY || state == ProtocolState.RESPONSE_DONE) {
            if (log.isDebugEnabled()) {
                log.debug(conn + ": Keep-Alive connection was closed: " +
                          getConnectionLoggingInfo(conn));
            }
        } else if (state == ProtocolState.REQUEST_BODY || state == ProtocolState.REQUEST_HEAD) {
            isFault = true;
            informReaderError(conn);
            log.warn("STATE_DESCRIPTION = Connection closed while server accepting request headers but prior to "
                    + "finish reading the request body, INTERNAL_STATE = " + state + ", DIRECTION = " + logDetails
                    .get("direction") + ", "
                    + "CAUSE_OF_ERROR = Connection between WSO2 Server and the Client has been closed, HTTP_URL = " + logDetails
                    .get("url") + ", " + "HTTP_METHOD = " + logDetails.get("method") + ", CLIENT_ADDRESS = "
                    + getClientConnectionInfo(conn)
                    + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID)
                    + ", CONNECTION = " + conn);
            if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                logHttpRequestErrorInCorrelationLog(conn, "Connection Closed in " + state.name());
            }
        } else if (state == ProtocolState.RESPONSE_BODY || state == ProtocolState.RESPONSE_HEAD) {
            isFault = true;
            informWriterError(conn);
            log.warn("STATE_DESCRIPTION = Connection closed while server writing the response headers or body, "
                    + "INTERNAL_STATE = " + state + ", DIRECTION = " + logDetails.get("direction") + ", "
                    + "CAUSE_OF_ERROR = Connection between WSO2 Server and the Client has been closed, HTTP_URL = " + logDetails
                    .get("url") + ", " + "HTTP_METHOD = " + logDetails.get("method") + ", CLIENT_ADDRESS = "
                    + getClientConnectionInfo(conn)
                    + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID)
                    + ", CONNECTION " + conn);
            if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                logHttpRequestErrorInCorrelationLog(conn, "Connection Closed in " + state.name());
            }
        } else if (state == ProtocolState.REQUEST_DONE) {
            isFault = true;
            informWriterError(conn);
            log.warn("STATE_DESCRIPTION = Connection closed after server accepting the request headers and the "
                    + "request body, INTERNAL_STATE = " + state + ", DIRECTION = " + logDetails.get("direction") + ", "
                    + "CAUSE_OF_ERROR = Connection between WSO2 Server and the Client has been closed, HTTP_URL = " + logDetails
                    .get("url") + ", " + "HTTP_METHOD = " + logDetails.get("method") + ", CLIENT_ADDRESS = "
                    + getClientConnectionInfo(conn)
                    + ", CORRELATION_ID = " + conn.getContext().getAttribute(CorrelationConstants.CORRELATION_ID)
                    + ", CONNECTION " + conn);
            if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                logHttpRequestErrorInCorrelationLog(conn, "Connection Closed in " + state.name());
            }
        }

        metrics.disconnected();

        SourceContext.updateState(conn, ProtocolState.CLOSED);
        
        if (conf.isTLSGracefulConnectionTerminationEnabled()) {
            sourceConfiguration.getSourceConnections().closeConnection(conn, isFault);
        } else {
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, isFault);
        }

        if (isFault) {
            rollbackTransaction(conn);
            metrics.exceptionOccured();
        }
    }

    public void endOfInput(NHttpServerConnection conn) throws IOException {
        conn.close();
    }

    public void exception(NHttpServerConnection conn, Exception ex) {
        boolean isFault = false;
        if (ex instanceof IOException) {
            /*
             * If the flow is SSE we have already set references to target connection and targetConnections
             * within the source connection so access them here and shut down target connection when source
             * connection is broken.
             * */
            if (conn != null && conn instanceof LoggingNHttpServerConnection) {
                LoggingNHttpClientConnection targetConnection =
                        (LoggingNHttpClientConnection) ((LoggingNHttpServerConnection) conn).getIOSession()
                                .getAttribute(SSE_TARGET_CONNECTION);
                TargetConnections targetConnections = (TargetConnections) ((LoggingNHttpServerConnection) conn)
                        .getIOSession().getAttribute(SSE_TARGET_CONNECTIONS);
                if (targetConnections != null && targetConnection != null) {
                    targetConnections.shutdownConnection(targetConnection, true);
                }
            }
            logIOException(conn, (IOException) ex);
            if (PassThroughCorrelationConfigDataHolder.isEnable()) {
                logHttpRequestErrorInCorrelationLog(conn, "IO Exception");
            }
            metrics.incrementFaultsReceiving();

            ProtocolState state = SourceContext.getState(conn);
            if (state == ProtocolState.REQUEST_BODY ||
                    state == ProtocolState.REQUEST_HEAD) {
                informReaderError(conn);
            } else if (state == ProtocolState.RESPONSE_BODY ||
                    state == ProtocolState.RESPONSE_HEAD) {
                informWriterError(conn);
            } else if (state == ProtocolState.REQUEST_DONE) {
                informWriterError(conn);
            } else if (state == ProtocolState.RESPONSE_DONE) {
                informWriterError(conn);
            }
            isFault = true;
            SourceContext.updateState(conn, ProtocolState.CLOSED);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
        } else if (ex instanceof MethodNotSupportedException) {
            isFault = generateHTTPErrorResponse(conn, ex, HttpVersion.HTTP_1_1, HttpStatus.SC_NOT_IMPLEMENTED,
                    "Not Implemented");
        } else if (ex instanceof HttpException) {
            isFault = generateHTTPErrorResponse(conn, ex, HttpVersion.HTTP_1_1, HttpStatus.SC_BAD_REQUEST,
                    "Bad request");
        } else {
            log.error("Unexpected error: " + ex.getMessage(), ex);
            SourceContext.updateState(conn, ProtocolState.CLOSED);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
            isFault = true;
        }

        if (isFault) {
            rollbackTransaction(conn);
        }
    }

    private boolean generateHTTPErrorResponse (NHttpServerConnection conn, Exception ex, HttpVersion version,
                                               int statusCode, String reason) {
        log.error("HttpException occurred ", ex);
        boolean isFault = false;
        if (PassThroughCorrelationConfigDataHolder.isEnable()) {
            logHttpRequestErrorInCorrelationLog(conn, "HTTP Exception");
        }
        try {
            if (conn.isResponseSubmitted()) {
                sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
                return false;
            }
            HttpContext httpContext = conn.getContext();

            HttpResponse response = new BasicHttpResponse(version, statusCode, reason);
            response.setParams(
                    new DefaultedHttpParams(sourceConfiguration.getHttpParams(), response.getParams()));
            response.addHeader(HTTP.CONN_DIRECTIVE, HTTP.CONN_CLOSE);

            // Pre-process HTTP request
            httpContext.setAttribute(ExecutionContext.HTTP_CONNECTION, conn);
            httpContext.setAttribute(ExecutionContext.HTTP_REQUEST, null);
            httpContext.setAttribute(ExecutionContext.HTTP_RESPONSE, response);

            sourceConfiguration.getHttpProcessor().process(response, httpContext);

            conn.submitResponse(response);
            SourceContext.updateState(conn, ProtocolState.CLOSED);
            informWriterError(conn);
            conn.close();
        } catch (Exception ex1) {
            log.error(ex1.getMessage(), ex1);
            SourceContext.updateState(conn, ProtocolState.CLOSED);
            sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
            isFault = true;
        }
        return isFault;
    }

    private Map<String, String> getLoggingInfo(NHttpServerConnection conn, ProtocolState state) {
        HashMap<String, String> logDetails = new HashMap<>();
        SourceContext sourceContext = SourceContext.get(conn);
        if (sourceContext != null) {
            String url = "", method = "";
            if (sourceContext.getRequest() != null) {
                url = sourceContext.getRequest().getUri();
                method = sourceContext.getRequest().getMethod();
            } else {
                HttpRequest httpRequest = conn.getHttpRequest();
                if (httpRequest != null) {
                    url = httpRequest.getRequestLine().getUri();
                    method = httpRequest.getRequestLine().getMethod();
                }
            }
            logDetails.put("url", url);
            logDetails.put("method", method);
        }
        if (state != null) {
            if (state.compareTo(ProtocolState.REQUEST_DONE) <= 0) {
                logDetails.put("direction", "REQUEST");
            } else {
                logDetails.put("direction", "RESPONSE");
            }
        }
        return logDetails;
    }

    private void handleInvalidState(NHttpServerConnection conn, String action) {
        log.warn(action + " while the handler is in an inconsistent state " +
                SourceContext.getState(conn));
        SourceContext.updateState(conn, ProtocolState.CLOSED);
        sourceConfiguration.getSourceConnections().shutDownConnection(conn, true);
    }

    public void informReaderError(NHttpServerConnection conn) {
        Pipe reader = SourceContext.get(conn).getReader();

        metrics.incrementFaultsReceiving();

        if (reader != null) {
            reader.producerError();
        } else {
            log.info("Reader null when calling informReaderError");
        }
    }

    public void informWriterError(NHttpServerConnection conn) {
        Pipe writer = SourceContext.get(conn).getWriter();

        metrics.incrementFaultsSending();

        if (writer != null) {
            writer.consumerError();
        } else {
            log.info("Writer null when calling informWriterError");
        }
    }
    
    /**
     * Commit the response to the connection. Processes the response through the configured
     * HttpProcessor and submits it to be sent out. This method hides any exceptions and is targetted
     * for non critical (i.e. browser requests etc) requests, which are not core messages
     * @param conn the connection being processed
     * @param response the response to commit over the connection
     */
    public void commitResponseHideExceptions(
            final NHttpServerConnection conn, final HttpResponse response) {
        try {
            conn.suspendInput();
            sourceConfiguration.getHttpProcessor().process(response, conn.getContext());
            conn.submitResponse(response);
        } catch (HttpException e) {
            handleException("Unexpected HTTP protocol error : " + e.getMessage(), e, conn);
        } catch (IOException e) {
            handleException("IO error submiting response : " + e.getMessage(), e, conn);
        }
    }
    /**
     * Shutting down the thread pools.
     */
    public void stop() {
        latencyView.destroy();
        s2sLatencyView.destroy();
        threadingView.destroy();
        try {
            if (sourceConfiguration.getWorkerPool() != null) {
                sourceConfiguration.getWorkerPool().shutdown(1000);
            }
        } catch (InterruptedException e) {
            log.warn("Error while shutting down worker thread pool. " + e.getMessage());
        }
    }
    
    // ----------- utility methods -----------

    private void handleException(String msg, Exception e, NHttpServerConnection conn) {
        log.error(msg, e);
        if (conn != null) {
            //shutdownConnection(conn);
        }
    }


    private void updateMetricsView(HttpContext context) {
        metrics.requestServed();
        if (context == null) {
            return;
        }
        latencyView.notifyTimes(new LatencyCollector(context, false));
        s2sLatencyView.notifyTimes(new LatencyCollector(context, true));
        LatencyCollector.clearTimestamps(context);
    }
    

    /**
     * Create synapse.response-source-buffer for GET and HEAD Http methods
     * @param method  Http Method
     * @param request Source Request
     * @return OutputStream
     */
    public OutputStream getOutputStream(String method,SourceRequest request){
        OutputStream os=null;
        if (HttpMethod.GET.equals(method) || HttpMethod.HEAD.equals(method)) {
            HttpContext context = request.getConnection().getContext();
            ContentOutputBuffer outputBuffer = new SimpleOutputBuffer(
                    sourceConfiguration.getIOBufferSize(), new HeapByteBufferAllocator());
            context.setAttribute("synapse.response-source-buffer",outputBuffer);
            os = new ContentOutputStream(outputBuffer);
        }
        return os;
    }

    /**
     * Create SourceRequest from NHttpServerConnection conn
     * @param conn the connection being processed
     * @return SourceRequest
     * @throws IOException
     * @throws HttpException
     */
    public SourceRequest getSourceRequest(NHttpServerConnection conn) throws IOException, HttpException {
        HttpContext context = conn.getContext();
        context.setAttribute(PassThroughConstants.REQ_ARRIVAL_TIME, System.currentTimeMillis());

        if (!SourceContext.assertState(conn, ProtocolState.REQUEST_READY) && !SourceContext.assertState(conn, ProtocolState.WSDL_RESPONSE_DONE)) {
            handleInvalidState(conn, "Request received");
            return null;
        }
        // we have received a message over this connection. So we must inform the pool
        sourceConfiguration.getSourceConnections().useConnection(conn);

        // at this point we have read the HTTP Headers
        SourceContext.updateState(conn, ProtocolState.REQUEST_HEAD);

        SourceRequest request = new SourceRequest(
                sourceConfiguration, conn.getHttpRequest(), conn);
        SourceContext.setRequest(conn, request);
        request.start(conn);
        metrics.incrementMessagesReceived();
        return request;
    }

    private void rollbackTransaction(NHttpServerConnection conn) {
        try {
            Long serverWorkerThreadId = (Long) conn.getContext().getAttribute(
                    PassThroughConstants.SERVER_WORKER_THREAD_ID);
            if (serverWorkerThreadId != null) {
                TranscationManger.rollbackTransaction(false,
                        serverWorkerThreadId);
            }
        } catch (Exception ex) {
            log.warn("Transaction rollback error after Connection closed "
                    + ex.getMessage() + conn);
        }
    }

    private void endTransaction(NHttpServerConnection conn) {
        try {
            Long serverWorkerThreadId = (Long) conn.getContext().getAttribute(
                    PassThroughConstants.SERVER_WORKER_THREAD_ID);
            if (serverWorkerThreadId != null) {
                TranscationManger.endTransaction(false, serverWorkerThreadId);
            }
        } catch (Exception ex) {
            log.warn("Transaction rollback error after Connection closed "
                    + ex.getMessage() + conn);
        }
    }

    private String getConnectionLoggingInfo(NHttpServerConnection conn) {
        if (conn instanceof LoggingNHttpServerConnection) {
            IOSession session = ((LoggingNHttpServerConnection) conn).getIOSession();
            if (session != null) {
                return " Remote Address : " + session.getRemoteAddress();
            }
        }
        return "";
    }

    private String getClientConnectionInfo(NHttpServerConnection conn) {
        if (conn instanceof LoggingNHttpServerConnection) {
            IOSession session = ((LoggingNHttpServerConnection) conn).getIOSession();
            if (session != null && session.getRemoteAddress() != null) {
                return session.getRemoteAddress().toString();
            }
        }
        return "";
    }

    private void logHttpRequestErrorInCorrelationLog(NHttpServerConnection conn, String state) {

        SourceContext sourceContext = SourceContext.get(conn);
        if (sourceContext != null) {
            String url = "", method = "";
            if (sourceContext.getRequest() != null) {
                url = sourceContext.getRequest().getUri();
                method = sourceContext.getRequest().getMethod();
            } else {
                HttpRequest httpRequest = conn.getHttpRequest();
                if (httpRequest != null) {
                    url = httpRequest.getRequestLine().getUri();
                    method = httpRequest.getRequestLine().getMethod();
                }
            }
            if ((method.length() != 0) && (url.length() != 0)) {
                if (conn.getContext().getAttribute(PassThroughConstants.REQ_ARRIVAL_TIME) != null) {
                    long startTime = (long) conn.getContext().getAttribute(PassThroughConstants.REQ_ARRIVAL_TIME);
                    ContextAwareLogger.getLogger(conn.getContext(), correlationLog, false).info(
                            (System.currentTimeMillis() - startTime) + "|HTTP|" + conn.getContext()
                                    .getAttribute("http.connection") + "|" + method + "|" + url + "|" + state);
                } else {
                    ContextAwareLogger.getLogger(conn.getContext(), correlationLog, false).info(
                            "|HTTP|" + conn.getContext().getAttribute("http.connection") + "|" + method + "|" + url
                                    + "|" + state);
                }
            }
        }
    }
}
