org.jboss.netty.example.http.file

Class HttpStaticFileServerHandler

java.lang.Object

org.jboss.netty.channel.SimpleChannelUpstreamHandler

org.jboss.netty.example.http.file.HttpStaticFileServerHandler

All Implemented Interfaces:

ChannelHandler, ChannelUpstreamHandler

public class HttpStaticFileServerHandler
extends SimpleChannelUpstreamHandler

A simple handler that serves incoming HTTP requests to send their respective HTTP responses. It also implements 'If-Modified-Since' header to take advantage of browser cache, as described in RFC 2616.

How Browser Caching Works

Web browser caching works with HTTP headers as illustrated by the following sample:

1. Request #1 returns the content of /file1.txt.
2. Contents of /file1.txt is cached by the browser.
3. Request #2 for /file1.txt 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.
4. The server knows the file has not been modified because the If-Modified-Since date is the same as the file's last modified date.

 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

 

Nested Class Summary

Nested classes/interfaces inherited from interface org.jboss.netty.channel.ChannelHandler

ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static int	HTTP_CACHE_SECONDS
(package private) static java.lang.String	HTTP_DATE_FORMAT
(package private) static java.lang.String	HTTP_DATE_GMT_TIMEZONE

Constructor Summary

Constructors

Constructor and Description
HttpStaticFileServerHandler()

Method Summary

Modifier and Type	Method and Description
void	exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) Invoked when an exception was raised by an I/O thread or a ChannelHandler.
void	messageReceived(ChannelHandlerContext ctx, MessageEvent e) Invoked when a message object (e.g: ChannelBuffer) was received from a remote peer.
private static java.lang.String	sanitizeUri(java.lang.String uri)
private static void	sendError(ChannelHandlerContext ctx, HttpResponseStatus status)
private static void	sendNotModified(ChannelHandlerContext ctx) When file timestamp is the same as what the browser is sending up, send a "304 Not Modified"
private static void	setContentTypeHeader(HttpResponse response, java.io.File file) Sets the content type header for the HTTP Response
private static void	setDateAndCacheHeaders(HttpResponse response, java.io.File fileToCache) Sets the Date and Cache headers for the HTTP Response
private static void	setDateHeader(HttpResponse response) Sets the Date header for the HTTP response

Methods inherited from class org.jboss.netty.channel.SimpleChannelUpstreamHandler

channelBound, channelClosed, channelConnected, channelDisconnected, channelInterestChanged, channelOpen, channelUnbound, childChannelClosed, childChannelOpen, handleUpstream, writeComplete

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

HTTP_DATE_FORMAT

static final java.lang.String HTTP_DATE_FORMAT

See Also:

Constant Field Values

HTTP_DATE_GMT_TIMEZONE

static final java.lang.String HTTP_DATE_GMT_TIMEZONE

See Also:

Constant Field Values

HTTP_CACHE_SECONDS

static final int HTTP_CACHE_SECONDS

See Also:

Constant Field Values

Constructor Detail

HttpStaticFileServerHandler

public HttpStaticFileServerHandler()

Method Detail

messageReceived

public void messageReceived(ChannelHandlerContext ctx,
                            MessageEvent e)
                     throws java.lang.Exception

Description copied from class: SimpleChannelUpstreamHandler

Invoked when a message object (e.g: ChannelBuffer) was received from a remote peer.

Overrides:

messageReceived in class SimpleChannelUpstreamHandler

Throws:

java.lang.Exception

exceptionCaught

public void exceptionCaught(ChannelHandlerContext ctx,
                            ExceptionEvent e)

Description copied from class: SimpleChannelUpstreamHandler

Invoked when an exception was raised by an I/O thread or a ChannelHandler.

Overrides:

exceptionCaught in class SimpleChannelUpstreamHandler

sanitizeUri

private static java.lang.String sanitizeUri(java.lang.String uri)

sendError

private static void sendError(ChannelHandlerContext ctx,
                              HttpResponseStatus status)

sendNotModified

private static void sendNotModified(ChannelHandlerContext ctx)

When file timestamp is the same as what the browser is sending up, send a "304 Not Modified"

setDateHeader

private static void setDateHeader(HttpResponse response)

Sets the Date header for the HTTP response

setDateAndCacheHeaders

private static void setDateAndCacheHeaders(HttpResponse response,
                                           java.io.File fileToCache)

Sets the Date and Cache headers for the HTTP Response

Parameters:

fileToCache - the file to extract content type

setContentTypeHeader

private static void setContentTypeHeader(HttpResponse response,
                                         java.io.File file)

Sets the content type header for the HTTP Response

Parameters:

file - the file to extract content type