# Access.java

    /*
     *  Licensed to the Apache Software Foundation (ASF) under one
     *  or more contributor license agreements.  See the NOTICE file
     *  distributed with this work for additional information
     *  regarding copyright ownership.  The ASF 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.http.access;

    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.http.Header;
    import org.apache.http.HttpMessage;
    import org.apache.http.HttpRequest;
    import org.apache.http.HttpResponse;
    import org.apache.http.params.HttpParams;
    import org.apache.synapse.transport.http.wrapper.HttpRequestWrapper;
    import org.apache.synapse.transport.http.wrapper.HttpResponseWrapper;

    import java.net.InetAddress;
    import java.util.ArrayList;
    import java.util.Date;
    import java.util.List;
    import java.util.Timer;
    import java.util.TimerTask;
    import java.util.concurrent.ConcurrentLinkedQueue;

    /**
     * The class to handle the HTTP Access Logs, patterns and the major functionality.
     * Major Code segment borrowed from Apache Tomcat's
     * org.apache.catalina.valves.AccessLogValve with thanks.
     */
    public class Access {
        private static Log log = LogFactory.getLog(Access.class);

        /**
         * Array of AccessLogElement, they will be used to make log message.
         */
        protected AccessLogElement[] logElements = null;

        protected String pattern = AccessConstants.getLogPattern();

        private static AccessLogger accessLogger;

        private static ConcurrentLinkedQueue<HttpRequestWrapper> requestQueue;
        private static ConcurrentLinkedQueue<HttpResponseWrapper> responseQueue;

        private static final int LOG_FREQUENCY_IN_SECONDS = 30;

        private Date date;

        /**
         * Constructor of AccessLog. AccessHandler has a static object of Access.
         *
         * @param log          - Log passed as a param. Default is Log of the same class.
         * @param accessLogger - AccessLogger Object
         */
        public Access(final Log log, AccessLogger accessLogger) {
            super();
            Access.log = log;
            Access.accessLogger = accessLogger;
            requestQueue = new ConcurrentLinkedQueue<HttpRequestWrapper>();
            responseQueue = new ConcurrentLinkedQueue<HttpResponseWrapper>();
            logElements = createLogElements();
            logAccesses();
        }

        /**
         * Adds the accesses to the queue.
         *
         * @param request - HttpRequest
         */
        public void addAccessToQueue(HttpRequest request) {
            HttpRequestWrapper requestWrapper = new HttpRequestWrapper();
            requestWrapper.setHttpRequest(request);
            requestWrapper.setDate(new Date(AccessTimeUtil.getDate().getTime()));
            requestQueue.add(requestWrapper);
        }

        /**
         * Adds the accesses to the queue.
         *
         * @param response - HttpResponse
         */
        public void addAccessToQueue(HttpResponse response) {
            HttpResponseWrapper responseWrapper = new HttpResponseWrapper();
            responseWrapper.setHttpResponse(response);
            responseWrapper.setDate(new Date(AccessTimeUtil.getDate().getTime()));
            responseQueue.add(responseWrapper);
        }

        /**
         * logs the request and response accesses.
         */
        public void logAccesses() {
            TimerTask logRequests = new LogRequests();
            TimerTask logResponses = new LogResponses();
            Timer requestTimer = new Timer();
            Timer responseTimer = new Timer();
            // Retry in 30 seconds
            long retryIn = 1000 * LOG_FREQUENCY_IN_SECONDS;
            requestTimer.schedule(logRequests, 0, retryIn);
            responseTimer.schedule(logResponses, 0, retryIn);
        }

        private class LogRequests extends TimerTask {
            public void run() {
                while (!requestQueue.isEmpty()) {
                    HttpRequestWrapper req = requestQueue.poll();
                    log(req, null);
                }
            }
        }

        private class LogResponses extends TimerTask {
            public void run() {
                while (!responseQueue.isEmpty()) {
                    HttpResponseWrapper res = responseQueue.poll();
                    log(null, res);
                }
            }
        }

        /**
         * The log method that is called from the NHttpClient and Server connection classes.
         *
         * @param request  - HttpRequest
         * @param response - HttpResponse
         */
        public void log(HttpRequest request, HttpResponse response) {
            date = AccessTimeUtil.getDate();
            //String commonLogFormatDate = AccessTimeUtil.getAccessDate(date);

            StringBuilder result = new StringBuilder(128);

            for (AccessLogElement logElement : logElements) {
                logElement.addElement(result, date, request, response);
            }
            String logString = result.toString();
            log.debug(logString);      //log to the console
            accessLogger.log(logString);      //log to the file
        }

        /**
         * gets the header values from the given message, with the given name.
         *
         * @param message - The message, HttpRequest or HttpResponse
         * @param name    - The header, which we need to get the value of.
         * @return - The header value.
         */
        protected static String getHeaderValues(HttpMessage message, String name) {
            int length = 0;
            Header[] header = new Header[0];
            StringBuffer headerValue = new StringBuffer();
            try {
                header = message.getHeaders(name);
                length = header.length;
            } catch (Exception e) {
                // The header doesn't exist
            }
            if (length == 0) {
                return "-";
            } else if (length == 1) {
                return header[0].getValue();
            } else {
                headerValue.append(header[0].getValue());
                for (int i = 1; i < length; i++) {
                    headerValue.append(" - ").append(header[i].getValue());
                }
            }
            return headerValue.toString();
        }

        protected static String getParam(HttpMessage message, String paramName) {
            HttpParams params = message.getParams();
            String param = (String) params.getParameter(paramName);
            if (param == null) {
                param = "-";
            }

            return param;
        }

        public static String getHostElement(HttpMessage message) {
            return getHeaderValues(message, "Host"); //%h;
        }

        public static String getLogicalUserNameElement(HttpMessage message) {
            if (message != null) {  //%l
                return "-";
            }
            return "";
        }

        public static String getUserNameElement(HttpMessage message) {
            return getHeaderValues(message, "From");     //%u
        }

        public static String getCookieElement(HttpMessage message) {
            return getHeaderValues(message, "Cookie");      // %c
        }

        public static String getRefererElement(HttpMessage message) {
            return getHeaderValues(message, "Referer"); //%{Referer}i;           %f
        }

        public static String getUserAgentElement(HttpMessage message) {
            return getHeaderValues(message, "User-Agent");           //%{User-Agent} %a
        }

        public static String getAcceptElement(HttpMessage message) {
            return getHeaderValues(message, "Accept");
        }

        public static String getAcceptLanguageElement(HttpMessage message) {
            return getHeaderValues(message, "Accept-Language");
        }

        public static String getAcceptEncodingElement(HttpMessage message) {
            return getHeaderValues(message, "Accept-Encoding");
        }

        public static String getAcceptCharSetElement(HttpMessage message) {
            return getHeaderValues(message, "Accept-Charset");
        }

        public static String getConnectionElement(HttpMessage message) {
            return getHeaderValues(message, "Connection");       //Keep-Alive
        }

        public static String getContentTypeElement(HttpMessage message) {
            return getHeaderValues(message, "Content-Type");
        }

        public static String getKeepAliveElement(HttpMessage message) {
            return getHeaderValues(message, "Keep-Alive");
        }

        public static String getTransferEncodingElement(HttpMessage message) {
            return getHeaderValues(message, "Transfer-Encoding");
        }

        public static String getContentEncodingElement(HttpMessage message) {
            return getHeaderValues(message, "Content-Encoding");
        }

        public static String getVaryElement(HttpMessage message) {
            return getHeaderValues(message, "Vary");
        }

        public static String getServerElement(HttpMessage message) {
            return getHeaderValues(message, "Server");
        }

        public static String getRemoteAddr(HttpMessage message) {
            return getParam(message, "http.remote.addr");
        }

        /**
         * AccessLogElement writes the partial message into the buffer.
         */
        protected interface AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response);
        }

        /**
         * write local IP address - %A
         */
        protected static class LocalAddrElement implements AccessLogElement {

            private static final String LOCAL_ADDR_VALUE;

            static {
                String init;
                try {
                    init = InetAddress.getLocalHost().getHostAddress();
                } catch (Throwable e) {
                    AccessTimeUtil.handleThrowable(e);
                    init = "127.0.0.1";
                }
                LOCAL_ADDR_VALUE = init;
            }

            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(LOCAL_ADDR_VALUE);
            }
        }

        /**
         * write remote host name - %h
         */
        protected static class HostElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                String remoteHost = "-";
                try {
                    if (request != null) {
                        remoteHost = getRemoteAddr(request);
                    } else if (response != null) {
                        remoteHost = getRemoteAddr(response);
                    }
                } catch (Exception e) {
                    // empty host
                }
                buf.append(remoteHost);
            }

        }

        /**
         * write remote logical username from identd (always returns '-') - %l
         */
        protected static class LogicalUserNameElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                String logicalUserName = "";
                try {
                    logicalUserName = getLogicalUserNameElement(request);
                } catch (Exception e) {
                    // empty logicalUserName
                }
                buf.append(logicalUserName);
            }
        }

        /**
         * write remote user that was authenticated (if any), else '-' - %u
         */
        protected static class UserElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                String userElement = "";
                try {
                    userElement = getUserNameElement(request);
                } catch (Exception e) {
                    // empty UserName
                }
                buf.append(userElement);
            }
        }

        /**
         * write date and time, in Common Log Format - %t
         */
        protected class DateAndTimeElement implements AccessLogElement {

            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {

                String currentDate = AccessTimeUtil.getAccessDate(date);
                buf.append(currentDate);
            }
        }

        /**
         * write first line of the request (method and request URI) - %r
         */
        protected static class RequestElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                if (request != null) {
                    String requestLine = request.getRequestLine().toString();
                    buf.append(requestLine);
                } else {
                    buf.append("- - ");
                }
            }
        }

        /**
         * write HTTP status code of the response - %s
         */
        protected static class HttpStatusCodeElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                if (response != null) {
                    int statusCode = response.getStatusLine().getStatusCode();
                    buf.append(statusCode); //getStatus
                } else {
                    buf.append('-');
                }
            }
        }

        /**
         * write bytes sent, excluding HTTP headers - %b, %B
         */
        protected static class ByteSentElement implements AccessLogElement {
            private boolean conversion;

            /**
             * if conversion is true, write '-' instead of 0 - %b
             *
             * @param conversion - To be conversed.
             */
            public ByteSentElement(boolean conversion) {
                this.conversion = conversion;
            }

            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                // Don't need to flush since trigger for log message is after the
                // response has been committed
                long length = -1;
                try {
                    if (request != null) {
                        String sLength = getHeaderValues(request, "Content-Length");
                        if(null != sLength && !"".equals(sLength)) {
                            length = Long.valueOf(sLength);
                        }
                    } else if (response != null) {
                        length = response.getEntity().getContentLength(); //getBytesWritten(false);
                    }

                    if (length <= 0 && conversion) {
                        buf.append('-');                           //%b
                    } else {
                        buf.append(length);
                    }
                } catch (Exception e) {
                    buf.append('-'); //No entity found.
                }
            }
        }

        /**
         * write request method (GET, POST, etc.) - %m
         */
        protected static class MethodElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                if (request != null) {
                    buf.append(request.getRequestLine().getMethod());
                }
            }
        }

        /**
         * write requested URL path - %U
         */
        protected static class RequestURIElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                if (request != null) {
                    String uri = request.getRequestLine().getUri().split("\\?")[0];
                    buf.append(uri);
                } else {
                    buf.append('-');
                }
            }
        }

        /**
         * write local server name - %v
         */
        protected static class LocalServerNameElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getHeaderValues(request, "server"));
            }
        }

        /**
         * write any string
         */
        protected static class StringElement implements AccessLogElement {
            private String str;

            public StringElement(String str) {
                this.str = str;
            }

            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(str);
            }
        }

        /**
         * write incoming headers - %{xxx}i
         */
        protected static class HeaderElement implements AccessLogElement {
            private String header;

            public HeaderElement(String header) {
                this.header = header;
            }

            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                try {
                    String value = getHeaderValues(request, header);
                    if (value == null) {
                        buf.append('-');
                    } else {
                        buf.append(value);
                    }
                } catch (Exception e) {
                    buf.append('-'); //Header is null
                }
            }
        }

        /**
         * write a specific cookie - %{xxx}c
         */
        protected static class CookieElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getCookieElement(request));
            }
        }

        /**
         * write the referer - %f
         */
        protected static class RefererElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getRefererElement(request));
            }
        }

        /**
         * write the user agent - %a
         */
        protected static class UserAgentElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getUserAgentElement(request));
            }
        }

        /**
         * write the Accept Element - %C
         */
        protected static class AcceptElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getAcceptElement(request));
            }
        }

        /**
         * write the Accept Language Element - %L
         */
        protected static class AcceptLanguageElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getAcceptLanguageElement(request));
            }
        }

        /**
         * write the Accept Encoding Element - %e
         */
        protected static class AcceptEncodingElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getAcceptEncodingElement(request));
            }
        }

        /**
         * write the Accept Character Set Element - %S
         */
        protected static class AcceptCharSetElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getAcceptCharSetElement(request));
            }
        }

        /**
         * write the Connection Element - %x
         */
        protected static class ConnectionElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getConnectionElement(request));
            }
        }

        /**
         * write the Content Type Element - %T
         */
        protected static class ContentTypeElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getContentTypeElement(request));
            }
        }

        /**
         * write the Keep Alive Element - %k
         */
        protected static class KeepAliveElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getKeepAliveElement(request));
            }
        }

        /**
         * write the Transfer Encoding Element - %E
         */
        protected static class TransferEncodingElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getTransferEncodingElement(request));
            }
        }

        /**
         * write the Content Encoding Element - %n
         */
        protected static class ContentEncodingElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getContentEncodingElement(request));
            }
        }

        /**
         * write the Vary Element - %V
         */
        protected static class VaryElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getVaryElement(request));
            }
        }

        /**
         * write the Server Element - %Z
         */
        protected static class ServerElement implements AccessLogElement {
            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                buf.append(getServerElement(request));
            }
        }

        /**
         * write a specific response header - %{xxx}o
         */
        protected static class ResponseHeaderElement implements AccessLogElement {
            private String header;

            public ResponseHeaderElement(String header) {
                this.header = header;
            }

            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                if (null != response) {
                    buf.append(getHeaderValues(response, header));
                }
                buf.append("-");
            }
        }

        /**
         * write an attribute in the ServletRequest - %{xxx}r    %R
         */
        protected static class RequestAttributeElement implements AccessLogElement {

            public RequestAttributeElement() {
            }

            public void addElement(StringBuilder buf, Date date, HttpRequest request,
                                   HttpResponse response) {
                Object value;
                if (request != null) {
                    value = request.getLastHeader(buf.toString()); //gets the attribute header
                } else {
                    value = "??";
                }
                if (value != null) {
                    if (value instanceof String) {
                        buf.append((String) value);
                    } else {
                        buf.append(value.toString());
                    }
                } else {
                    buf.append('-');
                }
            }

        }

        /**
         * parse pattern string and create the array of AccessLogElement
         *
         * @return Array of AccessLogElement
         */
        protected AccessLogElement[] createLogElements() {
            List<AccessLogElement> list = new ArrayList<AccessLogElement>();
            boolean replace = false;
            StringBuilder buf = new StringBuilder();
            for (int i = 0; i < pattern.length(); i++) {
                char ch = pattern.charAt(i);
                if (replace) {
                    /*
                     * For code that processes {, the behavior will be ... if I do
                     * not encounter a closing } - then I ignore the {
                     */
                    if ('{' == ch) {
                        StringBuilder name = new StringBuilder();
                        int j = i + 1;
                        for (; j < pattern.length() && '}' != pattern.charAt(j); j++) {
                            name.append(pattern.charAt(j));
                        }
                        if (j + 1 < pattern.length()) {
                            /* the +1 was to account for } which we increment now */
                            j++;
                            list.add(createAccessLogElement(name.toString(),
                                                            pattern.charAt(j)));
                            i = j; /* Since we walked more than one character */
                        } else {
                            // D'oh - end of string - pretend we never did this
                            // and do processing the "old way"
                            list.add(createAccessLogElement(ch));
                        }
                    } else {
                        list.add(createAccessLogElement(ch));
                    }
                    replace = false;
                } else if (ch == '%') {
                    replace = true;
                    list.add(new StringElement(buf.toString()));
                    buf = new StringBuilder();
                } else {
                    buf.append(ch);
                }
            }
            if (buf.length() > 0) {
                list.add(new StringElement(buf.toString()));
            }
            return list.toArray(new AccessLogElement[list.size()]);
        }

        /**
         * create an AccessLogElement implementation which needs header string
         *
         * @param header  - header of the request/response
         * @param pattern - pattern character given for the input element
         * @return AccessLogElement - accessLogElement
         */
        private AccessLogElement createAccessLogElement(String header, char pattern) {
            switch (pattern) {
                case 'i':
                    return new HeaderElement(header);  //%{xxx}i
                case 'o':
                    return new ResponseHeaderElement(header);
                case 'R':
                    return new RequestAttributeElement();
                default:
                    return new StringElement("???");
            }
        }

        /**
         * create an AccessLogElement implementation
         *
         * @param pattern - pattern character given for the input element
         * @return AccessLogElement acceessLogElement
         */
        private AccessLogElement createAccessLogElement(char pattern) {
            switch (pattern) {
                case 'A':
                    return new LocalAddrElement();
                case 'a':
                    return new UserAgentElement();
                case 'b':
                    return new ByteSentElement(true);     //%b
                case 'B':
                    return new ByteSentElement(false);
                case 'c':
                    return new CookieElement();            // %c
                case 'C':
                    return new AcceptElement();
                case 'e':
                    return new AcceptEncodingElement();
                case 'E':
                    return new TransferEncodingElement();
                case 'f':
                    return new RefererElement();
                case 'h':
                    return new HostElement();         //%h
                case 'k':
                    return new KeepAliveElement();
                case 'l':
                    return new LogicalUserNameElement();     //%l
                case 'L':
                    return new AcceptLanguageElement();
                case 'm':
                    return new MethodElement();
                case 'n':
                    return new ContentEncodingElement();
                case 'r':
                    return new RequestElement();        //%r
                case 'S':
                    return new AcceptCharSetElement();
                case 's':
                    return new HttpStatusCodeElement();       // %s
                case 'T':
                    return new ContentTypeElement();
                case 't':
                    return new DateAndTimeElement();       //%t
                case 'u':
                    return new UserElement();           //%u
                case 'U':
                    return new RequestURIElement();
                case 'V':
                    return new VaryElement();
                case 'v':
                    return new LocalServerNameElement();
                case 'x':
                    return new ConnectionElement();
                case 'Z':
                    return new ServerElement();
                default:
                    return new StringElement("???" + pattern + "???");
            }
        }

        /**
         * The log method that is called from the NHttpClient and Server connection classes.
         * This method is used to log the request/response with the actual date of operation.
         *
         * @param request  - HttpRequestWrapper
         * @param response - HttpResponseWrapper
         */
        public void log(HttpRequestWrapper request, HttpResponseWrapper response) {

            Date actualDateOfOperation = null;

            if(request != null) {
                actualDateOfOperation = request.getDate();
            } else if (response != null){
                actualDateOfOperation = response.getDate();
            }

            StringBuilder result = new StringBuilder(128);

            for (AccessLogElement logElement : logElements) {
                if (request != null)    {
                    logElement.addElement(result, actualDateOfOperation, request.getHttpRequest(), null);
                } else if (response != null)    {
                    logElement.addElement(result, actualDateOfOperation, null, response.getHttpResponse());
                }
            }
            String logString = result.toString();
            log.debug(logString);      //log to the console
            accessLogger.log(logString);      //log to the file
        }
    }