# RelayUtils.java

    /*
     *  Copyright (c) 2005-2010, 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.util;

    import com.google.gson.JsonParser;
    import org.apache.axiom.om.OMElement;
    import org.apache.axis2.AxisFault;
    import org.apache.axis2.Constants;
    import org.apache.axis2.addressing.AddressingConstants;
    import org.apache.axis2.addressing.AddressingHelper;
    import org.apache.axis2.context.ConfigurationContext;
    import org.apache.axis2.context.MessageContext;
    import org.apache.axis2.description.WSDL2Constants;
    import org.apache.axis2.engine.AxisConfiguration;
    import org.apache.axis2.engine.Handler;
    import org.apache.axis2.engine.Phase;
    import org.apache.axis2.transport.RequestResponseTransport;
    import org.apache.axis2.transport.TransportUtils;
    import org.apache.commons.io.IOUtils;
    import org.apache.commons.io.output.NullOutputStream;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.http.HttpEntityEnclosingRequest;
    import org.apache.synapse.transport.nhttp.NhttpConstants;
    import org.apache.synapse.transport.passthru.PassThroughConstants;
    import org.apache.synapse.transport.passthru.Pipe;
    import org.apache.synapse.transport.passthru.TargetRequest;
    import org.apache.synapse.transport.passthru.config.PassThroughConfiguration;

    import javax.xml.stream.XMLStreamException;
    import java.io.BufferedInputStream;
    import java.io.ByteArrayInputStream;
    import java.io.ByteArrayOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.util.LinkedHashSet;
    import java.util.List;
    import java.util.Map;

    public class RelayUtils {

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

        private static final DeferredMessageBuilder messageBuilder = new DeferredMessageBuilder();

        private static volatile Handler addressingInHandler = null;
        private static boolean noAddressingHandler = false;

        private static Boolean forcePTBuild = null;

        private static boolean forceXmlValidation = false;

        private static boolean forceJSONValidation = false;

        static {
            if (forcePTBuild == null) {
                forcePTBuild = PassThroughConfiguration.getInstance().getBooleanProperty(
                        PassThroughConstants.FORCE_PASSTHROUGH_BUILDER);
                if (forcePTBuild == null) {
                    forcePTBuild = true;
                }
                // this to keep track ignore the builder operation eventhough
                // content level is enable.
            }
            forceXmlValidation = PassThroughConfiguration.getInstance().isForcedXmlMessageValidationEnabled();
            forceJSONValidation = PassThroughConfiguration.getInstance().isForcedJSONMessageValidationEnabled();
        }

        public static void buildMessage(org.apache.axis2.context.MessageContext msgCtx)
                throws IOException, XMLStreamException {

            buildMessage(msgCtx, false);
        }

        public static void buildMessage(MessageContext messageContext, boolean earlyBuild)
                throws IOException, XMLStreamException {

            final Pipe pipe = (Pipe) messageContext.getProperty(PassThroughConstants.PASS_THROUGH_PIPE);

            if (messageContext.getProperty(Constants.Configuration.CONTENT_TYPE) != null) {
                if (log.isDebugEnabled()) {
                    log.debug("Content Type is " + messageContext.getProperty(Constants.Configuration.CONTENT_TYPE));
                }

                if (pipe != null
                    && !Boolean.TRUE.equals(messageContext
                                                    .getProperty(PassThroughConstants.MESSAGE_BUILDER_INVOKED)) && forcePTBuild) {
                    InputStream in = pipe.getInputStream();

                    Object http_sc = messageContext.getProperty(NhttpConstants.HTTP_SC);
                    if (http_sc != null && http_sc instanceof Integer && http_sc.equals(202)) {
                        if (in != null) {
                            InputStream bis = new ReadOnlyBIS(in);
                            int c = bis.read();
                            if (c == -1) {
                                messageContext.setProperty(PassThroughConstants.MESSAGE_BUILDER_INVOKED, Boolean.TRUE);
                                messageContext.setProperty(PassThroughConstants.NO_ENTITY_BODY, Boolean.TRUE);
                                return;
                            }
                            bis.reset();
                            in = bis;
                        }
                    }

                    buildMessage(messageContext, earlyBuild, in);
                    return;
                }
            } else {
                if (log.isDebugEnabled()) {
                    log.debug("Content Type is null and the message is not build");
                }
                messageContext.setProperty(PassThroughConstants.MESSAGE_BUILDER_INVOKED,
                        Boolean.TRUE);
                return;
            }
        }

        public static void buildMessage(MessageContext messageContext, boolean earlyBuild,
                                         InputStream in) throws IOException, AxisFault {
            ByteArrayOutputStream byteArrayOutputStream = null;
            if (forceXmlValidation || forceJSONValidation) {
                //read input stream to store raw data and create inputStream again.
                //then the raw data can be logged after an error while building the message.
                byteArrayOutputStream = new ByteArrayOutputStream();
                IOUtils.copy(in, byteArrayOutputStream);
                byteArrayOutputStream.flush();
                // Open new InputStreams using the recorded bytes and assign to in
                in =  new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
            }
            //
            BufferedInputStream bufferedInputStream = (BufferedInputStream) messageContext
                    .getProperty(PassThroughConstants.BUFFERED_INPUT_STREAM);
            if (bufferedInputStream != null) {
                try {
                    bufferedInputStream.reset();
                    bufferedInputStream.mark(0);
                } catch (Exception e) {
                    // just ignore the error
                }

            } else {
                bufferedInputStream = new BufferedInputStream(in);
                // TODO: need to handle properly for the moment lets use around 100k
                // buffer.
                bufferedInputStream.mark(128 * 1024);
                messageContext.setProperty(PassThroughConstants.BUFFERED_INPUT_STREAM,
                        bufferedInputStream);
            }

            OMElement element = null;
            try {
                element = messageBuilder.getDocument(messageContext,
                        bufferedInputStream != null ? bufferedInputStream : in);
                if (element != null) {
                    messageContext.setEnvelope(TransportUtils.createSOAPEnvelope(element));
                    messageContext.setProperty(DeferredMessageBuilder.RELAY_FORMATTERS_MAP,
                            messageBuilder.getFormatters());
                    messageContext.setProperty(PassThroughConstants.MESSAGE_BUILDER_INVOKED, Boolean.TRUE);

                    earlyBuild = messageContext.getProperty(PassThroughConstants.RELAY_EARLY_BUILD) != null ? (Boolean) messageContext
                            .getProperty(PassThroughConstants.RELAY_EARLY_BUILD) : earlyBuild;

                    if (!earlyBuild) {
                        processAddressing(messageContext);
                    }

                    //force validation makes sure that the xml is well formed (not having multi root element), and the json
                    // message is valid (not having any content after the final enclosing bracket)
                    if (forceXmlValidation || forceJSONValidation) {
                        String rawData = null;
                        try {
                            String contentType = (String) messageContext.getProperty(Constants.Configuration.CONTENT_TYPE);

                            if (PassThroughConstants.JSON_CONTENT_TYPE.equals(contentType) && forceJSONValidation) {
                                rawData = byteArrayOutputStream.toString();
                                JsonParser jsonParser = new JsonParser();
                                jsonParser.parse(rawData);
                            }

                            messageContext.getEnvelope().buildWithAttachments();
                            if (messageContext.getEnvelope().getBody().getFirstElement() != null) {
                                messageContext.getEnvelope().getBody().getFirstElement().buildNext();
                            }
                        } catch (Exception e) {
                            if (rawData == null) {
                                rawData = byteArrayOutputStream.toString();
                            }
                            log.error("Error while building the message.\n" + rawData);
                            messageContext.setProperty(PassThroughConstants.RAW_PAYLOAD, rawData);
                            throw e;
                        }
                    }
                }
            } catch (Exception e) {
                //Clearing the buffer when there is an exception occurred.
                consumeAndDiscardMessage(messageContext);
                messageContext.setProperty(PassThroughConstants.MESSAGE_BUILDER_INVOKED, Boolean.TRUE);
                handleException("Error while building Passthrough stream", e);
            }
            return;
        }

        /**
         * Function to check whether the processing request (enclosed within MessageContext) is a DELETE request without
         * entity body since we allow to have payload for DELETE requests, we treat same as POST. Hence this function can be
         * used to deviate DELETE requests without payloads
         * @param msgContext MessageContext
         * @return whether the request is a DELETE without payload
         */
        public static boolean isDeleteRequestWithoutPayload (MessageContext msgContext) {
            if (PassThroughConstants.HTTP_DELETE.equals(msgContext.getProperty(Constants.Configuration.HTTP_METHOD))) {

                //If message builder not invoked (Passthrough may contain entity body) OR delete with payload
                if (!Boolean.TRUE.equals(msgContext.getProperty(PassThroughConstants.MESSAGE_BUILDER_INVOKED)) ||
                        !Boolean.TRUE.equals(msgContext.getProperty(PassThroughConstants.NO_ENTITY_BODY))) {
                    //HTTP DELETE request with payload
                    return false;
                }
                //Empty payload delete request
                return true;
            }
            //Not a HTTP DELETE request
            return false;
        }

        /**
         * Check whether the we should overwrite the content type for the outgoing request.
         * @param msgContext MessageContext
         * @return whether to overwrite the content type for the outgoing request
         *
         */
        public static boolean shouldOverwriteContentType(MessageContext msgContext, TargetRequest request) {
            boolean builderInvoked = Boolean.TRUE.equals(msgContext
                    .getProperty(PassThroughConstants.MESSAGE_BUILDER_INVOKED));
            boolean noEntityBodySet =
                    Boolean.TRUE.equals(msgContext.getProperty(PassThroughConstants.NO_ENTITY_BODY));
            Map<String, LinkedHashSet<String>> headers = request.getHeaders();
            boolean contentTypeInRequest = false;
            if (headers.size() != 0 && (headers.get("Content-Type") != null || headers.get("content-type") != null)) {
                contentTypeInRequest = true;
            }
            boolean isDefaultContentTypeEnabled = false;
            ConfigurationContext configurationContex = msgContext.getConfigurationContext();
            if (configurationContex != null && configurationContex.getAxisConfiguration()
                    .getParameter(NhttpConstants.REQUEST_CONTENT_TYPE) != null) {
                isDefaultContentTypeEnabled = true;
            }
            // If builder is not invoked, which means the passthrough scenario, we should overwrite the content-type
            // depending on the presence of the incoming content-type.
            // If builder is invoked and no entity body property is not set (which means there is a payload in the request)
            // we should consider overwriting the content-type.
            return (builderInvoked && !noEntityBodySet) || contentTypeInRequest || isDefaultContentTypeEnabled;
        }

        /**
         * Function to check given inputstream is empty or not
         * Used to check whether content of the payload input stream is empty or not
         * @param inputStream target inputstream
         * @return true if it is a empty stream
         * @throws IOException
         */
        public static boolean isEmptyPayloadStream (InputStream inputStream) throws IOException {

            boolean isEmptyPayload = true;

            if (inputStream != null) {
                // read ahead few characters to see if the stream is valid.
                ReadOnlyBIS readOnlyStream = new ReadOnlyBIS(inputStream);

                /**
                * Checks for all empty or all whitespace streams and if found  sets isEmptyPayload to false. The while
                * loop exits if found any character other than space or end of stream reached.
                **/
                int c = readOnlyStream.read();
                while (c != -1) {
                    if (c != 32) {
                        //if not a space, should be some character in entity body
                        isEmptyPayload = false;
                        break;
                    }
                    c = readOnlyStream.read();
                }
                readOnlyStream.reset();
                inputStream.reset();
            }

            return isEmptyPayload;
        }

        private static void processAddressing(MessageContext messageContext) throws AxisFault {
            if (noAddressingHandler) {
                return;
            } else if (addressingInHandler == null) {
                synchronized (messageBuilder) {
                    if (addressingInHandler == null) {
                        AxisConfiguration axisConfig = messageContext.getConfigurationContext()
                                .getAxisConfiguration();
                        List<Phase> phases = axisConfig.getInFlowPhases();
                        boolean handlerFound = false;
                        for (Phase phase : phases) {
                            if ("Addressing".equals(phase.getName())) {
                                List<Handler> handlers = phase.getHandlers();
                                for (Handler handler : handlers) {
                                    if ("AddressingInHandler".equals(handler.getName())) {
                                        addressingInHandler = handler;
                                        handlerFound = true;
                                        break;
                                    }
                                }
                                break;
                            }
                        }

                        if (!handlerFound) {
                            noAddressingHandler = true;
                            return;
                        }
                    }
                }
            }

            messageContext.setProperty(AddressingConstants.DISABLE_ADDRESSING_FOR_IN_MESSAGES, "false");

            Object disableAddressingForOutGoing = null;
            if (messageContext.getProperty(AddressingConstants.DISABLE_ADDRESSING_FOR_OUT_MESSAGES) != null) {
                disableAddressingForOutGoing = messageContext
                        .getProperty(AddressingConstants.DISABLE_ADDRESSING_FOR_OUT_MESSAGES);
            }
            addressingInHandler.invoke(messageContext);

            if (disableAddressingForOutGoing != null) {
                messageContext.setProperty(AddressingConstants.DISABLE_ADDRESSING_FOR_OUT_MESSAGES,
                        disableAddressingForOutGoing);
            }

            if (messageContext.getAxisOperation() == null) {
                return;
            }

            String mepString = messageContext.getAxisOperation().getMessageExchangePattern();

            if (isOneWay(mepString)) {
                Object requestResponseTransport = messageContext
                        .getProperty(RequestResponseTransport.TRANSPORT_CONTROL);
                if (requestResponseTransport != null) {

                    Boolean disableAck = getDisableAck(messageContext);
                    if (disableAck == null || disableAck.booleanValue() == false) {
                        ((RequestResponseTransport) requestResponseTransport)
                                .acknowledgeMessage(messageContext);
                    }
                }
            } else if (AddressingHelper.isReplyRedirected(messageContext)
                    && AddressingHelper.isFaultRedirected(messageContext)) {
                if (mepString.equals(WSDL2Constants.MEP_URI_IN_OUT)
                        || mepString.equals(WSDL2Constants.MEP_URI_IN_OUT)
                        || mepString.equals(WSDL2Constants.MEP_URI_IN_OUT)) {
                    // OR, if 2 way operation but the response is intended to not
                    // use the response channel of a 2-way transport
                    // then we don't need to keep the transport waiting.

                    Object requestResponseTransport = messageContext
                            .getProperty(RequestResponseTransport.TRANSPORT_CONTROL);
                    if (requestResponseTransport != null) {

                        // We should send an early ack to the transport whenever
                        // possible, but some modules need
                        // to use the back channel, so we need to check if they have
                        // disabled this code.
                        Boolean disableAck = getDisableAck(messageContext);

                        if (disableAck == null || disableAck.booleanValue() == false) {
                            ((RequestResponseTransport) requestResponseTransport)
                                    .acknowledgeMessage(messageContext);
                        }

                    }
                }
            }
        }

        private static Boolean getDisableAck(MessageContext msgContext) throws AxisFault {
            // We should send an early ack to the transport whenever possible, but
            // some modules need
            // to use the back channel, so we need to check if they have disabled
            // this code.
            Boolean disableAck = (Boolean) msgContext
                    .getProperty(Constants.Configuration.DISABLE_RESPONSE_ACK);
            if (disableAck == null) {
                disableAck = (Boolean) (msgContext.getAxisService() != null ? msgContext
                        .getAxisService().getParameterValue(
                                Constants.Configuration.DISABLE_RESPONSE_ACK) : null);
            }

            return disableAck;
        }

        private static boolean isOneWay(String mepString) {
            return (mepString.equals(WSDL2Constants.MEP_URI_IN_ONLY)
                    || mepString.equals(WSDL2Constants.MEP_URI_IN_ONLY) || mepString
                    .equals(WSDL2Constants.MEP_URI_IN_ONLY));
        }

        /**
         * Perform an error log message to all logs @ ERROR and throws a AxisFault
         *
         * @param msg the log message
         * @param e   an Exception encountered
         * @throws AxisFault
         */
        private static void handleException(String msg, Exception e) throws AxisFault {
            log.error(msg, e);
            throw new AxisFault(msg, e);
        }

        /**
         * Consumes the data in pipe completely in the given message context and discard it
         *
         * @param pipe Pass through pipe
         * @throws AxisFault
         */
        private static void consume(Pipe pipe) throws AxisFault {
            InputStream in = pipe.getInputStream();
            if (in != null) {
                try {
                    if (pipe.isConsumeRequired()) {
                        IOUtils.copy(in, new NullOutputStream());
                    }
                } catch (IOException exception) {
                    handleException("Error when consuming the input stream to discard", exception);
                }
            }

        }

        /**
         * Consumes the data in pipe completely in the given message context and discard it
         *
         * @param msgContext Axis2 Message context which contains the data
         * @throws AxisFault AxisFault
         */
        public static void consumeAndDiscardMessage(MessageContext msgContext) throws AxisFault {
            final Pipe pipe = (Pipe) msgContext.getProperty(PassThroughConstants.PASS_THROUGH_PIPE);
            if (pipe != null) {
                try {
                    while (!pipe.isProducerCompleted() || pipe.isConsumeRequired()) {
                        consume(pipe);
                        if (pipe.isProducerError()) {
                            break;
                        }
                    }
                } catch (IOException exception) {
                    handleException("Error when consuming the input stream to discard", exception);
                }
            }
        }

        /**
         * An Un-closable, Read-Only, Reusable, BufferedInputStream
         */
        private static class ReadOnlyBIS extends BufferedInputStream {
            private static final String LOG_STREAM = "org.apache.synapse.transport.passthru.util.ReadOnlyStream";
            private static final Log logger = LogFactory.getLog(LOG_STREAM);

            public ReadOnlyBIS(InputStream inputStream) {
                super(inputStream);
                super.mark(Integer.MAX_VALUE);
                if (logger.isDebugEnabled()) {
                    logger.debug("<init>");
                }
            }

            @Override
            public void close() throws IOException {
                super.reset();
                //super.mark(Integer.MAX_VALUE);
                if (logger.isDebugEnabled()) {
                    logger.debug("#close");
                }
            }

            @Override
            public void mark(int readlimit) {
                if (logger.isDebugEnabled()) {
                    logger.debug("#mark");
                }
            }

            @Override
            public boolean markSupported() {
                return true; //but we don't mark.
            }

            @Override
            public long skip(long n) {
                if (logger.isDebugEnabled()) {
                    logger.debug("#skip");
                }
                return 0;
            }
        }
    }