# LoggingStreamInterceptor.java

    /*
     * Copyright (c) 2021, 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.transport.passthru;

    import org.apache.axis2.context.MessageContext;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;

    import java.nio.ByteBuffer;
    import java.nio.charset.Charset;

    /**
     * Sample stream interceptor, which intercepts source and target request to print the stream passing via the engine.
     * <pre>
     * {@code
     * <interceptors xmlns:svns="http://org.wso2.securevault/configuration">
     *     <interceptor class="org.apache.synapse.transport.passthru.LoggingStreamInterceptor">
     *         <parameter name="charset" value="ISO-8859-1"/>
     *         <parameter name="enableInterception" value="true"/>
     *     </interceptor>
     * </interceptors>
     * }
     * </pre>
     */
    public class LoggingStreamInterceptor extends DefaultStreamInterceptor {

        private static final Log log = LogFactory.getLog(LoggingStreamInterceptor.class);

        private static final String INPUT = ">>>";
        private static final String OUTPUT = "<<<";

        private String charset = Charset.defaultCharset().toString();
        private boolean enableInterception = false;

        @Override
        public boolean interceptSourceRequest(MessageContext axisCtx) {
            return enableInterception;
        }

        @Override
        public boolean sourceRequest(ByteBuffer buffer, MessageContext ctx) {
            printStream(buffer, INPUT);
            return true;
        }

        @Override
        public boolean interceptTargetRequest(MessageContext axisCtx) {
            return enableInterception;
        }

        @Override
        public void targetRequest(ByteBuffer buffer, MessageContext ctx) {
            printStream(buffer, OUTPUT);
        }

        @Override
        public boolean interceptTargetResponse(MessageContext axisCtx) {
            return enableInterception;
        }

        @Override
        public boolean targetResponse(ByteBuffer buffer, MessageContext ctx) {
            printStream(buffer, INPUT);
            return true;
        }

        @Override
        public boolean interceptSourceResponse(MessageContext axisCtx) {
            return enableInterception;
        }

        @Override
        public void sourceResponse(ByteBuffer buffer, MessageContext ctx) {
            printStream(buffer, OUTPUT);
        }

        private void printStream(ByteBuffer stream, String direction) {

            Charset charsetValue = Charset.forName(this.charset);
            String text = charsetValue.decode(stream).toString();
            log.info(direction + " " + text);
        }

        public void setCharset(String charset) {

            this.charset = charset;
            if (log.isDebugEnabled()) {
                log.debug("Charset : " + charset);
            }
        }

        public void setEnableInterception(boolean enableInterception) {
            this.enableInterception = enableInterception;
        }
    }