ResponseCallback.java

/*
 * Copyright (c) 2015, 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.wso2.carbon.transport.http.netty.listener;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.http.DefaultHttpContent;
import io.netty.handler.codec.http.HttpContent;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.LastHttpContent;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.wso2.carbon.messaging.CarbonCallback;
import org.wso2.carbon.messaging.CarbonMessage;
import org.wso2.carbon.messaging.DefaultCarbonMessage;
import org.wso2.carbon.transport.http.netty.common.Constants;
import org.wso2.carbon.transport.http.netty.common.Util;
import org.wso2.carbon.transport.http.netty.internal.HTTPTransportContextHolder;
import org.wso2.carbon.transport.http.netty.message.HTTPCarbonMessage;

import java.nio.ByteBuffer;

/**
 * A Class responsible for handling the response.
 */
public class ResponseCallback implements CarbonCallback {

    private ChannelHandlerContext ctx;

    private static final Logger logger = LoggerFactory.getLogger(ResponseCallback.class);
    private RequestDataHolder requestDataHolder;

    public ResponseCallback(ChannelHandlerContext channelHandlerContext, CarbonMessage requestMsg) {
        this.ctx = channelHandlerContext;
        requestDataHolder = new RequestDataHolder(requestMsg);
    }

    public void done(CarbonMessage cMsg) {

        boolean connectionCloseAfterResponse = shouldConnectionClose(cMsg);

        Util.prepareBuiltMessageForTransfer(cMsg);
        Util.setupTransferEncodingForResponse(cMsg, requestDataHolder);

        if (HTTPTransportContextHolder.getInstance().getHandlerExecutor() != null) {
            HTTPTransportContextHolder.getInstance().getHandlerExecutor().executeAtSourceResponseReceiving(cMsg);
        }
        final HttpResponse response = Util.createHttpResponse(cMsg, connectionCloseAfterResponse);

        ctx.write(response);

        if (!cMsg.isBufferContent()) {
            cMsg.setWriter(new ResponseContentWriter(ctx));
        } else {
            if (cMsg instanceof HTTPCarbonMessage) {
                HTTPCarbonMessage nettyCMsg = (HTTPCarbonMessage) cMsg;
                while (true) {
                    if (nettyCMsg.isEndOfMsgAdded() && nettyCMsg.isEmpty()) {
                        ChannelFuture future = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
                        if (connectionCloseAfterResponse) {
                            future.addListener(ChannelFutureListener.CLOSE);
                        }
                        break;
                    }
                    HttpContent httpContent = nettyCMsg.getHttpContent();
                    if (httpContent instanceof LastHttpContent) {
                        ChannelFuture future = ctx.writeAndFlush(httpContent);
                        if (connectionCloseAfterResponse) {
                            future.addListener(ChannelFutureListener.CLOSE);
                        }
                        if (HTTPTransportContextHolder.getInstance().getHandlerExecutor() != null) {
                            HTTPTransportContextHolder.getInstance().getHandlerExecutor().
                                    executeAtSourceResponseSending(cMsg);
                        }
                        break;
                    }
                    ctx.write(httpContent);
                }
            } else if (cMsg instanceof DefaultCarbonMessage) {
                DefaultCarbonMessage defaultCMsg = (DefaultCarbonMessage) cMsg;
                if (defaultCMsg.isEndOfMsgAdded() && defaultCMsg.isEmpty()) {
                    ChannelFuture future = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
                    if (connectionCloseAfterResponse) {
                        future.addListener(ChannelFutureListener.CLOSE);
                    }
                    return;
                }
                while (true) {
                    ByteBuffer byteBuffer = defaultCMsg.getMessageBody();
                    ByteBuf bbuf = Unpooled.wrappedBuffer(byteBuffer);
                    DefaultHttpContent httpContent = new DefaultHttpContent(bbuf);
                    ctx.write(httpContent);
                    if (defaultCMsg.isEndOfMsgAdded() && defaultCMsg.isEmpty()) {
                        ChannelFuture future = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
                        if (HTTPTransportContextHolder.getInstance().getHandlerExecutor() != null) {
                            HTTPTransportContextHolder.getInstance().getHandlerExecutor().
                                    executeAtSourceResponseSending(cMsg);
                        }
                        if (connectionCloseAfterResponse) {
                            future.addListener(ChannelFutureListener.CLOSE);
                        }
                        break;
                    }
                }
            }
        }
    }

    // Decides whether to close the connection after sending the response
    private boolean shouldConnectionClose(CarbonMessage responseMsg) {
        String responseConnectionHeader = responseMsg.getHeader(Constants.HTTP_CONNECTION);
        String requestConnectionHeader = requestDataHolder.getConnectionHeader();
        if ((responseConnectionHeader != null &&
             Constants.CONNECTION_CLOSE.equalsIgnoreCase(responseConnectionHeader))
            || (requestConnectionHeader != null &&
                Constants.CONNECTION_CLOSE.equalsIgnoreCase(requestConnectionHeader))) {
            return true;
        }
        return false;
    }

}