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Added handing of HTTP headers with respect to browser caching and cache validation.

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Veebs 2011-03-05 15:40:34 +11:00 committed by Trustin Lee
parent e00e9bb8fa
commit a85249ced8
1 changed files with 132 additions and 1 deletions
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131
src/main/java/org/jboss/netty/example/http/file/HttpStaticFileServerHandler.java
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@ -26,6 +26,13 @@ import java.io.FileNotFoundException;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.TimeZone;
import javax.activation.MimetypesFileTypeMap;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
@ -40,6 +47,7 @@ import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;
import org.jboss.netty.handler.codec.frame.TooLongFrameException;
import org.jboss.netty.handler.codec.http.DefaultHttpResponse;
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.HttpResponseStatus;
@ -48,11 +56,50 @@ import org.jboss.netty.handler.stream.ChunkedFile;
import org.jboss.netty.util.CharsetUtil;
/**
* Web browser caching works with HTTP headers as illustrated by the following sample.
* <ul>
* <li>Request #1 returns the content of <code>/file1.txt</code>.</li>
* <li>Contents of <code>/file1.txt</code> is cached by the browser.</li>
* <li>Request #2 for <code>/file1.txt</code> does return the contents of the file again. Rather,
* a 304 Not Modified is returned. This tells the browser to use the contents stored in its cache.</li>
* <li>The server knows the file has not been modified because the <code>If-Modified-Since</code> date is the
* same as the file's last modified date.</li>
* </ul>
*
* <pre>
* Request #1 Headers
* ===================
* GET /file1.txt HTTP/1.1
*
* Response #1 Headers
* ===================
* HTTP/1.1 200 OK
* Date: Tue, 01 Mar 2011 22:44:26 GMT
* Last-Modified: Wed, 30 Jun 2010 21:36:48 GMT
* Expires: Tue, 01 Mar 2012 22:44:26 GMT
* Cache-Control: private, max-age=31536000
*
* Request #2 Headers
* ===================
* GET /file1.txt HTTP/1.1
* If-Modified-Since: Wed, 30 Jun 2010 21:36:48 GMT
*
* Response #2 Headers
* ===================
* HTTP/1.1 304 Not Modified
* Date: Tue, 01 Mar 2011 22:44:28 GMT
*
* </pre>
*
* @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
* @author <a href="http://gleamynode.net/">Trustin Lee</a>
*/
public class HttpStaticFileServerHandler extends SimpleChannelUpstreamHandler {
public static final String HTTP_DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss zzz";
public static final String HTTP_DATE_GMT_TIMEZONE = "GMT";
public static final int HTTP_CACHE_SECONDS = 60;
@Override
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
HttpRequest request = (HttpRequest) e.getMessage();
@ -77,6 +124,19 @@ public class HttpStaticFileServerHandler extends SimpleChannelUpstreamHandler {
return;
}
// Cache Validation
String ifModifiedSince = request.getHeader(HttpHeaders.Names.IF_MODIFIED_SINCE);
if (ifModifiedSince != null && !ifModifiedSince.equals(""))
{
SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT);
Date ifModifiedSinceDate = dateFormatter.parse(ifModifiedSince);
if (ifModifiedSinceDate.getTime() == file.lastModified())
{
sendNotModified(ctx);
return;
}
}
RandomAccessFile raf;
try {
raf = new RandomAccessFile(file, "r");
@ -88,6 +148,8 @@ public class HttpStaticFileServerHandler extends SimpleChannelUpstreamHandler {
HttpResponse response = new DefaultHttpResponse(HTTP_1_1, OK);
setContentLength(response, fileLength);
setContentTypeHeader(response, file);
setDateAndCacheHeaders(response, file);
Channel ch = e.getChannel();
@ -178,4 +240,73 @@ public class HttpStaticFileServerHandler extends SimpleChannelUpstreamHandler {
// Close the connection as soon as the error message is sent.
ctx.getChannel().write(response).addListener(ChannelFutureListener.CLOSE);
}
/**
* When file timestamp is the same as what the browser is sending up, send a "304 Not Modified"
*
* @param ctx
* Context
*/
private void sendNotModified(ChannelHandlerContext ctx) {
HttpResponse response = new DefaultHttpResponse(HTTP_1_1, HttpResponseStatus.NOT_MODIFIED);
setDateHeader(response);
// Close the connection as soon as the error message is sent.
ctx.getChannel().write(response).addListener(ChannelFutureListener.CLOSE);
}
/**
* Sets the Date header for the HTTP response
*
* @param response
* HTTP response
* @param file
* file to extract content type
*/
private void setDateHeader(HttpResponse response) {
SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT);
dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));
Calendar time = new GregorianCalendar();
response.setHeader(HttpHeaders.Names.DATE, dateFormatter.format(time.getTime()));
}
/**
* Sets the Date and Cache headers for the HTTP Response
*
* @param response
* HTTP response
* @param file
* file to extract content type
*/
private void setDateAndCacheHeaders(HttpResponse response, File filetoCache) {
SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT);
dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));
// Date header
Calendar time = new GregorianCalendar();
response.setHeader(HttpHeaders.Names.DATE, dateFormatter.format(time.getTime()));
// Add cache headers
time.add(Calendar.SECOND, HTTP_CACHE_SECONDS);
response.setHeader(HttpHeaders.Names.EXPIRES, dateFormatter.format(time.getTime()));
response.setHeader(HttpHeaders.Names.CACHE_CONTROL, "private, max-age=" + HTTP_CACHE_SECONDS);
response.setHeader(HttpHeaders.Names.LAST_MODIFIED, dateFormatter.format(new Date(filetoCache.lastModified())));
}
/**
* Sets the content type header for the HTTP Response
*
* @param response
* HTTP response
* @param file
* file to extract content type
*/
private void setContentTypeHeader(HttpResponse response, File file) {
MimetypesFileTypeMap mimeTypesMap = new MimetypesFileTypeMap();
response.setHeader(HttpHeaders.Names.CONTENT_TYPE, mimeTypesMap.getContentType(file.getPath()));
}
}