# SourceResponse.java

    /**
     *  Copyright (c) 2009, 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.apache.synapse.transport.passthru;

    import org.apache.axiom.om.OMOutputFormat;
    import org.apache.axis2.AxisFault;
    import org.apache.axis2.context.MessageContext;
    import org.apache.axis2.transport.MessageFormatter;
    import org.apache.axis2.util.MessageProcessorSelector;
    import org.apache.http.ConnectionReuseStrategy;
    import org.apache.http.HttpException;
    import org.apache.http.HttpRequest;
    import org.apache.http.HttpResponse;
    import org.apache.http.HttpStatus;
    import org.apache.http.HttpVersion;
    import org.apache.http.ProtocolVersion;
    import org.apache.http.entity.BasicHttpEntity;
    import org.apache.http.impl.DefaultConnectionReuseStrategy;
    import org.apache.http.nio.ContentEncoder;
    import org.apache.http.nio.NHttpServerConnection;
    import org.apache.http.params.DefaultedHttpParams;
    import org.apache.http.protocol.ExecutionContext;
    import org.apache.http.protocol.HTTP;
    import org.apache.synapse.transport.passthru.config.SourceConfiguration;
    import org.apache.synapse.transport.passthru.util.PassThroughTransportUtils;
    import org.apache.synapse.transport.passthru.util.RelayUtils;

    import java.io.ByteArrayOutputStream;
    import java.io.IOException;
    import java.util.HashMap;
    import java.util.Iterator;
    import java.util.Map;
    import java.util.Set;
    import java.util.TreeSet;

    public class SourceResponse {
        private Pipe pipe = null;
        /** Transport headers */
        private Map<String, TreeSet<String>> headers = new HashMap<String, TreeSet<String>>();
        /** Status of the response */
        private int status = HttpStatus.SC_OK;
        /** Status line */
        private String statusLine = null;
        /** Actual response submitted */
        private HttpResponse response = null;
        /** Configuration of the receiver */
        private SourceConfiguration sourceConfiguration;
        /** Version of the response */
        private ProtocolVersion version = HttpVersion.HTTP_1_1;
        /** Connection strategy */
        private ConnectionReuseStrategy connStrategy = new DefaultConnectionReuseStrategy();
        /** Chunk response or not */
        // private boolean chunk = true;
        /** response has an entity or not**/
        private boolean hasEntity = true;
        /** Keep alive request */
        private boolean keepAlive = true;
        private SourceRequest request = null;

        /** If version change required default HTTP 1.1 will be overridden*/
        private boolean versionChangeRequired =false;

        public SourceResponse(SourceConfiguration config, int status, SourceRequest request) {
            this(config, status, null, request);
        }

        public SourceResponse(SourceConfiguration config, int status, String statusLine,
                              SourceRequest request) {
            this.status = status;
            this.statusLine = statusLine;
            this.sourceConfiguration = config;
            this.request = request;
            if (request != null && request.getVersion() != null) {
                this.version = request.getVersion();
            }
        }

        public void connect(Pipe pipe) {
            this.pipe = pipe;

            if (request != null && pipe != null) {
                SourceContext.get(request.getConnection()).setWriter(pipe);
            }
        }

        /**
         * Starts the response by writing the headers
         * @param conn connection
         * @throws java.io.IOException if an error occurs
         * @throws org.apache.http.HttpException if an error occurs
         */
        public void start(NHttpServerConnection conn) throws IOException, HttpException {
            // create the response
            response = sourceConfiguration.getResponseFactory().newHttpResponse(
                    request.getVersion(), this.status,
                    request.getConnection().getContext());

            if (statusLine != null) {
                response.setStatusLine(version, status, statusLine);
            } else if (versionChangeRequired){
            	response.setStatusLine(version, status);
            } else {
                response.setStatusCode(status);
            }

            BasicHttpEntity entity = null;

            if (canResponseHaveBody(request.getRequest(), response)) {
                entity = new BasicHttpEntity();

                long contentLength = -1;
                String contentLengthHeader = null;
                if (headers.get(HTTP.CONTENT_LEN) != null && headers.get(HTTP.CONTENT_LEN).size() > 0) {
                    contentLengthHeader = headers.get(HTTP.CONTENT_LEN).first();
                }

                if (contentLengthHeader != null) {
                    contentLength = Long.parseLong(contentLengthHeader);
                    headers.remove(HTTP.CONTENT_LEN);
                }

                if (contentLength != -1) {
                    entity.setChunked(false);
                    entity.setContentLength(contentLength);
                } else {
                    entity.setChunked(true);
                }

            }

            response.setEntity(entity);

            // set any transport headers
            Set<Map.Entry<String, TreeSet<String>>> entries = headers.entrySet();

            for (Map.Entry<String, TreeSet<String>> entry : entries) {
                if (entry.getKey() != null) {
                	Iterator<String> i = entry.getValue().iterator();
                    while(i.hasNext()) {
                    	response.addHeader(entry.getKey(), i.next());
                    }
                }
            }
    		if (!keepAlive) {
    			response.setHeader(HTTP.CONN_DIRECTIVE, HTTP.CONN_CLOSE);
    		}
            response.setParams(new DefaultedHttpParams(response.getParams(),
                                                       sourceConfiguration.getHttpParams()));

            SourceContext.updateState(conn, ProtocolState.RESPONSE_HEAD);

            // Pre-process HTTP response
            conn.getContext().setAttribute(ExecutionContext.HTTP_CONNECTION, conn);
            conn.getContext().setAttribute(ExecutionContext.HTTP_RESPONSE, response);
            conn.getContext().setAttribute(ExecutionContext.HTTP_REQUEST,
                    SourceContext.getRequest(conn).getRequest());

            sourceConfiguration.getHttpProcessor().process(response, conn.getContext());

            //Since HTTP HEAD request doesn't contain message body, entity will be null when above HttpProcessor()
            // process invoked. Hence content length is set to 0 inside the HTTP-Core. To avoid that content length of
            // the backend response is set as the content length.
            if (entity == null &&
                PassThroughConstants.HTTP_HEAD.equalsIgnoreCase(request.getRequest().getRequestLine().getMethod())) {
                if (response.getFirstHeader(PassThroughConstants.ORGINAL_CONTEN_LENGTH) == null && response.getFirstHeader(
    		            HTTP.CONTENT_LEN).getValue() != null && (response.getFirstHeader(HTTP.CONTENT_LEN).getValue().equals("0"))) {
                    response.removeHeaders(HTTP.CONTENT_LEN);
                } else {
                    response.removeHeaders(HTTP.CONTENT_LEN);
                    response.addHeader(HTTP.CONTENT_LEN,
                                       response.getFirstHeader(PassThroughConstants.ORGINAL_CONTEN_LENGTH).getValue());
                    response.removeHeaders(PassThroughConstants.ORGINAL_CONTEN_LENGTH);
                }
            }

            conn.submitResponse(response);

            // Handle non entity body responses
            if (entity == null) {
                hasEntity = false;
                // Reset connection state
                sourceConfiguration.getSourceConnections().releaseConnection(conn);
                // Make ready to deal with a new request
                conn.requestInput();
            }
        }

    	public void checkResponseChunkDisable(MessageContext responseMsgContext) throws IOException {
            if (responseMsgContext.getProperty(PassThroughConstants.HTTP_SC) != null){
                if (this.canResponseHaveContentLength(responseMsgContext)) {
                    calculateContentlengthForChunckDisabledResponse(responseMsgContext);
                }
            } else {
                calculateContentlengthForChunckDisabledResponse(responseMsgContext);
            }
    	}

        /**
         * Calculates the content-length when chunking is disabled.
         * @param responseMsgContext outflow message context
         * @throws IOException
         */
        private void calculateContentlengthForChunckDisabledResponse(MessageContext responseMsgContext) throws IOException {
            String forceHttp10 = (String) responseMsgContext.getProperty(PassThroughConstants.FORCE_HTTP_1_0);
            if ("true".equals(forceHttp10) || responseMsgContext.isPropertyTrue(PassThroughConstants.DISABLE_CHUNKING, false)) {
                if (!responseMsgContext.isPropertyTrue(PassThroughConstants.MESSAGE_BUILDER_INVOKED,
                        false)) {
                    try {
                        RelayUtils.buildMessage(responseMsgContext, false);
                        responseMsgContext.getEnvelope().buildWithAttachments();
                    } catch (Exception e) {
                        throw new AxisFault(e.getMessage());
                    }
                }

                if("true".equals(forceHttp10)){
                    version = HttpVersion.HTTP_1_0;
                    versionChangeRequired=true;
                }

                Boolean noEntityBody =
                        (Boolean) responseMsgContext.getProperty(PassThroughConstants.NO_ENTITY_BODY);

                if (noEntityBody != null && Boolean.TRUE == noEntityBody) {
                    headers.remove(HTTP.CONTENT_TYPE);
                    return;
                }

                MessageFormatter formatter = MessageProcessorSelector.getMessageFormatter(responseMsgContext);
                OMOutputFormat format = PassThroughTransportUtils.getOMOutputFormat(responseMsgContext);
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                formatter.writeTo(responseMsgContext, format, out, false);
                TreeSet<String> header = new TreeSet<String>();
                header.add(String.valueOf(out.toByteArray().length));
                headers.put(HTTP.CONTENT_LEN, header);
            }
        }

        /**
         * Consume the content through the Pipe and write them to the wire
         * @param conn connection
         * @param encoder encoder
         * @throws java.io.IOException if an error occurs
         * @return number of bytes written
         */
        public int write(NHttpServerConnection conn, ContentEncoder encoder) throws IOException {
            int bytes = 0;
            if (pipe != null) {
                bytes = pipe.consume(encoder);
            } else {
                encoder.complete();
            }
            // Update connection state
            if (encoder.isCompleted()) {
                SourceContext.updateState(conn, ProtocolState.RESPONSE_DONE);

                sourceConfiguration.getMetrics().
                        notifySentMessageSize(conn.getMetrics().getSentBytesCount());

                if (response != null && !this.connStrategy.keepAlive(response, conn.getContext())) {
                    SourceContext.updateState(conn, ProtocolState.CLOSING);

                    sourceConfiguration.getSourceConnections().closeConnection(conn);
                } else if (SourceContext.get(conn).isShutDown()) {
                    // we need to shut down if the shutdown flag is set
                    SourceContext.updateState(conn, ProtocolState.CLOSING);

                    sourceConfiguration.getSourceConnections().closeConnection(conn);
                } else {
                    // Reset connection state
                    sourceConfiguration.getSourceConnections().releaseConnection(conn);
                    // Ready to deal with a new request
                    conn.requestInput();
                }
            }
            return bytes;
        }

        public void addHeader(String name, String value) {
        	if(headers.get(name) == null) {
        		TreeSet<String> values = new TreeSet<String>();
        		values.add(value);
        		headers.put(name, values);
        	} else {
        		TreeSet<String> values = headers.get(name);
        		values.add(value);
        	}
        }

        public void setStatus(int status) {
            this.status = status;
        }
        public void removeHeader(String name) {
            if (headers.get(name) != null) {
                headers.remove(name);
            }
        }

        public String getHeader(String name) {
            if (headers.containsKey(name)){
                return headers.get(name).first();
            }
            return null;
        }

        private boolean canResponseHaveBody(final HttpRequest request, final HttpResponse response) {
            if (request != null && "HEAD".equalsIgnoreCase(request.getRequestLine().getMethod())) {
                return false;
            }
            int status = response.getStatusLine().getStatusCode();
            return status >= HttpStatus.SC_OK
                   && status != HttpStatus.SC_NO_CONTENT
                   && status != HttpStatus.SC_NOT_MODIFIED
                   && status != HttpStatus.SC_RESET_CONTENT;
        }

        /**
         * Checks whether response can have Content-Length header
         * @param responseMsgContext out flow message context
         * @return true if response can have Content-Length header else false
         */
        private boolean canResponseHaveContentLength(MessageContext responseMsgContext) {
            Object httpStatus = responseMsgContext.getProperty(PassThroughConstants.HTTP_SC);
            int status;
            if (httpStatus == null || httpStatus.toString().equals("")) {
                return false;
            }
            if (httpStatus instanceof String) {
                status = Integer.parseInt((String)httpStatus);
            } else {
                status = (Integer) httpStatus;
            }
            if (request != null && PassThroughConstants.HTTP_CONNECT.equals(request.getRequest().getRequestLine()
                                                                                    .getMethod())) {
                return (status / 100 != 2);
            } else {
                return HttpStatus.SC_NO_CONTENT != status && (status / 100 != 1);
            }
        }

        public boolean hasEntity() {
           return this.hasEntity;
        }

    	public void setKeepAlive(boolean keepAlive) {
    		this.keepAlive = keepAlive;
    	}

    }