# HttpResponseProcessHandler.java

    /*
     * Copyright (c) 2019, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
     *
     * WSO2 Inc. 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.
     */

    package org.apache.synapse.commons.emulator.http.consumer;

    import io.netty.buffer.ByteBuf;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelInboundHandlerAdapter;
    import io.netty.handler.codec.http.*;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.synapse.commons.emulator.http.dsl.HttpConsumerContext;

    import static io.netty.handler.codec.http.HttpResponseStatus.CONTINUE;
    import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;

    public class HttpResponseProcessHandler extends ChannelInboundHandlerAdapter {
        private static final Log log = LogFactory.getLog(HttpResponseProcessHandler.class);
        private HttpRequestContext httpRequestContext;
        private HttpRequestInformationProcessor httpRequestInformationProcessor;
        private HttpResponseProcessor httpResponseProcessor;
        private HttpConsumerContext consumerContext;

        public HttpResponseProcessHandler(HttpConsumerContext consumerContext) {
            this.consumerContext = consumerContext;
        }

        @Override
        public void channelActive(ChannelHandlerContext ctx) throws Exception {
        }

        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) {
            if (msg instanceof HttpRequest) {
                readingDelay(consumerContext.getReadingDelay());
                this.httpRequestContext = new HttpRequestContext();
                this.httpRequestInformationProcessor = new HttpRequestInformationProcessor();
                this.httpResponseProcessor = new HttpResponseProcessor(consumerContext);
                HttpRequest httpRequest = (HttpRequest) msg;

                if (HttpHeaders.is100ContinueExpected(httpRequest)) {
                    send100Continue(ctx);
                }
                httpRequestInformationProcessor.process(httpRequest, httpRequestContext);
            } else {
                if (msg instanceof HttpContent) {
                    HttpContent httpContent = (HttpContent) msg;
                    ByteBuf content = httpContent.content();
                    if (content.isReadable()) {
                        httpRequestInformationProcessor.appendDecoderResult(httpRequestContext, httpContent, content);
                    }
                }

                if (msg instanceof LastHttpContent) {
                    ctx.fireChannelReadComplete();
                }
            }
        }

        @Override
        public void channelReadComplete(ChannelHandlerContext ctx) {
            if (httpResponseProcessor != null) {
                waitingDelay(consumerContext.getWritingDelay());
                this.httpResponseProcessor.process(httpRequestContext, ctx);
            }
            ctx.flush();
        }

        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
            log.error("Exception occurred while processing the response", cause);
            ctx.close();
        }

        private static void send100Continue(ChannelHandlerContext ctx) {
            FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, CONTINUE);
            ctx.write(response);
        }

        private void readingDelay(int delay) {
            try {
                if (delay > 0) {
                    Thread.sleep(delay);
                }
            } catch (InterruptedException e) {
                log.error("Exception occurred while processing the reading delay", e);
            }
        }

        private void waitingDelay(int delay) {
            try {
                if (delay > 0) {
                    Thread.sleep(delay);
                }
            } catch (InterruptedException e) {
                log.error("Exception occurred while processing the waiting delay", e);
            }
        }
    }