/*
    * Copyright 2012 The Netty Project
    *
    * The Netty Project 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.jboss.netty.example.http.snoop;
  
  import static org.jboss.netty.handler.codec.http.HttpHeaders.*;
  import static org.jboss.netty.handler.codec.http.HttpHeaders.Names.*;
  import static org.jboss.netty.handler.codec.http.HttpResponseStatus.*;
  import static org.jboss.netty.handler.codec.http.HttpVersion.*;
  
  import java.util.List;
  import java.util.Map;
  import java.util.Map.Entry;
  import java.util.Set;
  
  import org.jboss.netty.buffer.ChannelBuffer;
  import org.jboss.netty.buffer.ChannelBuffers;
  import org.jboss.netty.channel.ChannelFuture;
  import org.jboss.netty.channel.ChannelFutureListener;
  import org.jboss.netty.channel.ChannelHandlerContext;
  import org.jboss.netty.channel.ExceptionEvent;
  import org.jboss.netty.channel.MessageEvent;
  import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
  import org.jboss.netty.handler.codec.http.Cookie;
  import org.jboss.netty.handler.codec.http.CookieDecoder;
  import org.jboss.netty.handler.codec.http.CookieEncoder;
  import org.jboss.netty.handler.codec.http.DefaultHttpResponse;
  import org.jboss.netty.handler.codec.http.HttpChunk;
  import org.jboss.netty.handler.codec.http.HttpChunkTrailer;
  import org.jboss.netty.handler.codec.http.HttpHeaders;
  import org.jboss.netty.handler.codec.http.HttpRequest;
  import org.jboss.netty.handler.codec.http.HttpResponse;
  import org.jboss.netty.handler.codec.http.QueryStringDecoder;
  import org.jboss.netty.util.CharsetUtil;
  
  public class HttpSnoopServerHandler extends SimpleChannelUpstreamHandler {
  
      private HttpRequest request;
      private boolean readingChunks;
      /** Buffer that stores the response content */
      private final StringBuilder buf = new StringBuilder();
  
      @Override
      public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
          if (!readingChunks) {
              HttpRequest request = this.request = (HttpRequest) e.getMessage();
  
              if (is100ContinueExpected(request)) {
                  send100Continue(e);
              }
  
              buf.setLength(0);
              buf.append("WELCOME TO THE WILD WILD WEB SERVER\r\n");
              buf.append("===================================\r\n");
  
              buf.append("VERSION: " + request.getProtocolVersion() + "\r\n");
              buf.append("HOSTNAME: " + getHost(request, "unknown") + "\r\n");
              buf.append("REQUEST_URI: " + request.getUri() + "\r\n\r\n");
  
              for (Map.Entry<String, String> h: request.getHeaders()) {
                  buf.append("HEADER: " + h.getKey() + " = " + h.getValue() + "\r\n");
              }
              buf.append("\r\n");
  
              QueryStringDecoder queryStringDecoder = new QueryStringDecoder(request.getUri());
              Map<String, List<String>> params = queryStringDecoder.getParameters();
              if (!params.isEmpty()) {
                  for (Entry<String, List<String>> p: params.entrySet()) {
                      String key = p.getKey();
                      List<String> vals = p.getValue();
                      for (String val : vals) {
                          buf.append("PARAM: " + key + " = " + val + "\r\n");
                      }
                  }
                  buf.append("\r\n");
              }
  
              if (request.isChunked()) {
                  readingChunks = true;
              } else {
                  ChannelBuffer content = request.getContent();
                  if (content.readable()) {
                      buf.append("CONTENT: " + content.toString(CharsetUtil.UTF_8) + "\r\n");
                  }
                  writeResponse(e);
              }
          } else {
             HttpChunk chunk = (HttpChunk) e.getMessage();
             if (chunk.isLast()) {
                 readingChunks = false;
                 buf.append("END OF CONTENT\r\n");
 
                 HttpChunkTrailer trailer = (HttpChunkTrailer) chunk;
                 if (!trailer.getHeaderNames().isEmpty()) {
                     buf.append("\r\n");
                     for (String name: trailer.getHeaderNames()) {
                         for (String value: trailer.getHeaders(name)) {
                             buf.append("TRAILING HEADER: " + name + " = " + value + "\r\n");
                         }
                     }
                     buf.append("\r\n");
                 }
 
                 writeResponse(e);
             } else {
                 buf.append("CHUNK: " + chunk.getContent().toString(CharsetUtil.UTF_8) + "\r\n");
             }
         }
     }
 
     private void writeResponse(MessageEvent e) {
         // Decide whether to close the connection or not.
         boolean keepAlive = isKeepAlive(request);
 
         // Build the response object.
         HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
         response.setContent(ChannelBuffers.copiedBuffer(buf.toString(), CharsetUtil.UTF_8));
         response.setHeader(CONTENT_TYPE, "text/plain; charset=UTF-8");
 
         if (keepAlive) {
             // Add 'Content-Length' header only for a keep-alive connection.
             response.setHeader(CONTENT_LENGTH, response.getContent().readableBytes());
             // Add keep alive header as per:
             // - http://www.w3.org/Protocols/HTTP/1.1/draft-ietf-http-v11-spec-01.html#Connection
             response.setHeader(CONNECTION, HttpHeaders.Values.KEEP_ALIVE);
         }
 
         // Encode the cookie.
         String cookieString = request.getHeader(COOKIE);
         if (cookieString != null) {
             CookieDecoder cookieDecoder = new CookieDecoder();
             Set<Cookie> cookies = cookieDecoder.decode(cookieString);
             if (!cookies.isEmpty()) {
                 // Reset the cookies if necessary.
                 CookieEncoder cookieEncoder = new CookieEncoder(true);
                 for (Cookie cookie : cookies) {
                     cookieEncoder.addCookie(cookie);
                     response.addHeader(SET_COOKIE, cookieEncoder.encode());
                 }
             }
         } else {
             // Browser sent no cookie.  Add some.
             CookieEncoder cookieEncoder = new CookieEncoder(true);
             cookieEncoder.addCookie("key1", "value1");
             response.addHeader(SET_COOKIE, cookieEncoder.encode());
             cookieEncoder.addCookie("key2", "value2");
             response.addHeader(SET_COOKIE, cookieEncoder.encode());
         }
 
         // Write the response.
         ChannelFuture future = e.getChannel().write(response);
 
         // Close the non-keep-alive connection after the write operation is done.
         if (!keepAlive) {
             future.addListener(ChannelFutureListener.CLOSE);
         }
     }
 
     private static void send100Continue(MessageEvent e) {
         HttpResponse response = new DefaultHttpResponse(HTTP_1_1, CONTINUE);
         e.getChannel().write(response);
     }
 
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e)
             throws Exception {
         e.getCause().printStackTrace();
         e.getChannel().close();
     }
 }