io.netty.example.http.file

Class HttpStaticFileServerHandler

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.SimpleChannelInboundHandler<io.netty.handler.codec.http.FullHttpRequest>

io.netty.example.http.file.HttpStaticFileServerHandler

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler

public class HttpStaticFileServerHandler
extends io.netty.channel.SimpleChannelInboundHandler<io.netty.handler.codec.http.FullHttpRequest>

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 io.netty.channel.ChannelHandler

io.netty.channel.ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field and Description
static int	HTTP_CACHE_SECONDS
static String	HTTP_DATE_FORMAT
static String	HTTP_DATE_GMT_TIMEZONE

Constructor Summary

Constructors

Constructor and Description
HttpStaticFileServerHandler()

Method Summary

Methods

Modifier and Type	Method and Description
void	channelRead0(io.netty.channel.ChannelHandlerContext ctx, io.netty.handler.codec.http.FullHttpRequest request)
void	exceptionCaught(io.netty.channel.ChannelHandlerContext ctx, Throwable cause)

Methods inherited from class io.netty.channel.SimpleChannelInboundHandler

acceptInboundMessage, channelRead

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelInactive, channelReadComplete, channelRegistered, channelUnregistered, channelWritabilityChanged, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

handlerAdded, handlerRemoved

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty.channel.ChannelHandler

handlerAdded, handlerRemoved

Field Detail

HTTP_DATE_FORMAT

public static final String HTTP_DATE_FORMAT

See Also:

Constant Field Values

HTTP_DATE_GMT_TIMEZONE

public static final String HTTP_DATE_GMT_TIMEZONE

See Also:

Constant Field Values

HTTP_CACHE_SECONDS

public static final int HTTP_CACHE_SECONDS

See Also:

Constant Field Values

Constructor Detail

HttpStaticFileServerHandler

public HttpStaticFileServerHandler()

Method Detail

channelRead0

public void channelRead0(io.netty.channel.ChannelHandlerContext ctx,
                io.netty.handler.codec.http.FullHttpRequest request)
                  throws Exception

Specified by:

channelRead0 in class io.netty.channel.SimpleChannelInboundHandler<io.netty.handler.codec.http.FullHttpRequest>

Throws:

Exception

exceptionCaught

public void exceptionCaught(io.netty.channel.ChannelHandlerContext ctx,
                   Throwable cause)
                     throws Exception

Specified by:

exceptionCaught in interface io.netty.channel.ChannelHandler

Overrides:

exceptionCaught in class io.netty.channel.ChannelHandlerAdapter

Throws:

Exception