# DeferredMessageBuilder.java

    /*
     * Copyright (c) 2022. 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.netty.util;

    import org.apache.axiom.om.OMElement;
    import org.apache.axiom.soap.SOAPEnvelope;
    import org.apache.axiom.soap.impl.llom.soap11.SOAP11Factory;
    import org.apache.axis2.AxisFault;
    import org.apache.axis2.Constants;
    import org.apache.axis2.builder.ApplicationXMLBuilder;
    import org.apache.axis2.builder.Builder;
    import org.apache.axis2.builder.BuilderUtil;
    import org.apache.axis2.builder.MIMEBuilder;
    import org.apache.axis2.builder.MTOMBuilder;
    import org.apache.axis2.builder.SOAPBuilder;
    import org.apache.axis2.builder.XFormURLEncodedBuilder;
    import org.apache.axis2.context.MessageContext;
    import org.apache.axis2.transport.MessageFormatter;
    import org.apache.axis2.transport.TransportUtils;
    import org.apache.axis2.transport.http.ApplicationXMLFormatter;
    import org.apache.axis2.transport.http.HTTPConstants;
    import org.apache.axis2.transport.http.MultipartFormDataFormatter;
    import org.apache.axis2.transport.http.SOAPMessageFormatter;
    import org.apache.axis2.transport.http.XFormURLEncodedFormatter;
    import org.apache.axis2.util.MessageProcessorSelector;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.synapse.transport.netty.BridgeConstants;

    import java.io.IOException;
    import java.io.InputStream;
    import java.util.HashMap;
    import java.util.Map;
    import javax.xml.stream.XMLStreamException;

    /**
     * Class DeferredMessageBuilder contains the tools required to build the payload.
     */
    public class DeferredMessageBuilder {

        private static final Log LOG = LogFactory.getLog(DeferredMessageBuilder.class);

        public static final String RELAY_FORMATTERS_MAP = "__RELAY_FORMATTERS_MAP";

        private Map<String, Builder> builders = new HashMap<String, Builder>();
        private Map<String, MessageFormatter> formatters = new HashMap<String, MessageFormatter>();

        public DeferredMessageBuilder() {
            // first initialize with the default builders
            builders.put("multipart/related", new MIMEBuilder());
            builders.put("application/soap+xml", new SOAPBuilder());
            builders.put("text/xml", new SOAPBuilder());
            builders.put("application/xop+xml", new MTOMBuilder());
            builders.put("application/xml", new ApplicationXMLBuilder());
            builders.put("application/x-www-form-urlencoded",
                    new XFormURLEncodedBuilder());

            // initialize the default formatters
            formatters.put("application/x-www-form-urlencoded", new XFormURLEncodedFormatter());
            formatters.put("multipart/form-data", new MultipartFormDataFormatter());
            formatters.put("application/xml", new ApplicationXMLFormatter());
            formatters.put("text/xml", new SOAPMessageFormatter());
            formatters.put("application/soap+xml", new SOAPMessageFormatter());
        }

        public Map<String, Builder> getBuilders() {

            return builders;
        }

        public void addBuilder(String contentType, Builder builder) {

            builders.put(contentType, builder);
        }

        public void addFormatter(String contentType, MessageFormatter messageFormatter) {

            formatters.put(contentType, messageFormatter);
        }

        public Map<String, MessageFormatter> getFormatters() {

            return formatters;
        }

        public OMElement getDocument(MessageContext msgCtx, InputStream in) throws
                XMLStreamException, IOException {

            // HTTP Delete requests may contain entity body or not. Hence if the request is a HTTP DELETE, we have to verify
            // that the payload stream is empty or not.
            if (HTTPConstants.HEADER_DELETE.equals(msgCtx.getProperty(Constants.Configuration.HTTP_METHOD)) &&
                    MessageUtils.isEmptyPayloadStream(in)) {
                msgCtx.setProperty(BridgeConstants.NO_ENTITY_BODY, Boolean.TRUE);
                return TransportUtils.createSOAPEnvelope(null);
            }

            String contentType = (String) msgCtx.getProperty(Constants.Configuration.CONTENT_TYPE);
            String contentType1 = getContentType(contentType, msgCtx);

            Map transportHeaders = (Map) msgCtx.getProperty(MessageContext.TRANSPORT_HEADERS);

            String contentLength = null;
            String transferEncoded;
            if (transportHeaders != null) {
                contentLength = (String) transportHeaders.get(BridgeConstants.CONTENT_LEN);
                transferEncoded = (String) transportHeaders.get(BridgeConstants.TRANSFER_ENCODING);

                if (contentType.equals(BridgeConstants.CONTENT_TYPE_APPLICATION_OCTET_STREAM)
                        && (contentLength == null || Integer.parseInt(contentLength) == 0)
                        && transferEncoded == null) {
                    msgCtx.setProperty(BridgeConstants.NO_ENTITY_BODY, true);
                    msgCtx.setProperty(Constants.Configuration.CONTENT_TYPE, "");
                    return new SOAP11Factory().getDefaultEnvelope();
                }
            }

            OMElement element = null;
            Builder builder;
            if (contentType != null) {
                // loading builder from externally..
                // builder = configuration.getMessageBuilder(_contentType,useFallbackBuilder);
                builder = MessageProcessorSelector.getMessageBuilder(contentType1, msgCtx);
                if (builder != null) {
                    try {
                        if ("0".equals(contentLength)) {
                            element = new SOAP11Factory().getDefaultEnvelope();
                            //since we are setting an empty envelop to achieve the empty body, we have to set a different
                            //content-type other than text/xml, application/soap+xml or any other content-type which will
                            //invoke the soap builder, otherwise soap builder will get hit and an empty envelope
                            // will be send out
                            msgCtx.setProperty(Constants.Configuration.MESSAGE_TYPE, "application/xml");
                        } else {
                            element = builder.processDocument(in, contentType, msgCtx);
                        }
                    } catch (AxisFault axisFault) {
                        LOG.error("Error building message", axisFault);
                        throw axisFault;
                    }
                }
            }

            if (element == null) {
                if (msgCtx.isDoingREST()) {
                    try {
                        element = BuilderUtil.getPOXBuilder(in, null).getDocumentElement();
                    } catch (XMLStreamException e) {
                        LOG.error("Error building message using POX Builder", e);
                        throw e;
                    }
                } else {
                    // switch to default
                    builder = new SOAPBuilder();
                    try {
                        if ("0".equals(contentLength)) {
                            element = new SOAP11Factory().getDefaultEnvelope();
                            //since we are setting an empty envelop to achieve the empty body, we have to set a different
                            //content-type other than text/xml, application/soap+xml or any other content-type which will
                            //invoke the soap builder, otherwise soap builder will get hit and an empty envelope
                            // will be send out
                            msgCtx.setProperty(Constants.Configuration.MESSAGE_TYPE, "application/xml");
                        } else {
                            element = builder.processDocument(in, contentType, msgCtx);
                        }
                    } catch (AxisFault axisFault) {
                        LOG.error("Error building message using SOAP builder");
                        throw axisFault;
                    }
                }
            }

            // build the soap headers and body
            if (element instanceof SOAPEnvelope) {
                SOAPEnvelope env = (SOAPEnvelope) element;
                env.hasFault();
            }

            // setting up original contentType (resetting the content type)
            if (contentType != null && !contentType.isEmpty()) {
                msgCtx.setProperty(Constants.Configuration.CONTENT_TYPE, contentType);
            }
            return element;
        }

        /**
         * This method is from org.apache.axis2.transport.TransportUtils - it was a hack placed in Axis2 Transport to enable
         * responses with text/xml to be processed using the ApplicationXMLBuilder (which is technically wrong, it should be
         * the duty of the backend service to send the correct content type, which makes the most sense (refer RFC 1049),
         * alas, tis not the way of the World).
         *
         * @param contentType content type
         * @param msgContext  message context
         * @return MIME content type.
         */
        public static String getContentType(String contentType, MessageContext msgContext) {

            String type;
            int index = contentType.indexOf(';');
            if (index > 0) {
                type = contentType.substring(0, index);
            } else {
                int commaIndex = contentType.indexOf(',');
                if (commaIndex > 0) {
                    type = contentType.substring(0, commaIndex);
                } else {
                    type = contentType;
                }
            }
            // Some services send REST responses as text/xml. We should convert it to
            // application/xml if its a REST response, if not it will try to use the SOAPMessageBuilder.
            // isDoingREST should already be properly set by HTTPTransportUtils.initializeMessageContext
            if (null != msgContext.getProperty(BridgeConstants.INVOKED_REST)
                    && msgContext.getProperty(BridgeConstants.INVOKED_REST).equals(true)
                    && HTTPConstants.MEDIA_TYPE_TEXT_XML.equals(type)) {
                type = HTTPConstants.MEDIA_TYPE_APPLICATION_XML;
            }
            return type;
        }
    }