Package io.netty.handler.codec.http.websocketx.extensions

Class WebSocketServerExtensionHandler

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.ChannelDuplexHandler

io.netty.handler.codec.http.websocketx.extensions.WebSocketServerExtensionHandler

All Implemented Interfaces:

ChannelHandler, ChannelInboundHandler, ChannelOutboundHandler

Direct Known Subclasses:

WebSocketServerCompressionHandler

public class WebSocketServerExtensionHandler
extends ChannelDuplexHandler

This handler negotiates and initializes the WebSocket Extensions. It negotiates the extensions based on the client desired order, ensures that the successfully negotiated extensions are consistent between them, and initializes the channel pipeline with the extension decoder and encoder. Find a basic implementation for compression extensions at io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketServerCompressionHandler.

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor	Description
WebSocketServerExtensionHandler(WebSocketServerExtensionHandshaker... extensionHandshakers)	Constructor

Method Summary

Modifier and Type	Method	Description
void	channelRead(ChannelHandlerContext ctx, java.lang.Object msg)	Calls ChannelHandlerContext.fireChannelRead(Object) to forward to the next ChannelInboundHandler in the ChannelPipeline.
protected void	onHttpRequestChannelRead(ChannelHandlerContext ctx, HttpRequest request)	This is a method exposed to perform fail-fast checks of user-defined http types.
protected void	onHttpResponseWrite(ChannelHandlerContext ctx, HttpResponse response, ChannelPromise promise)	This is a method exposed to perform fail-fast checks of user-defined http types.
void	write(ChannelHandlerContext ctx, java.lang.Object msg, ChannelPromise promise)	Calls ChannelOutboundInvoker.write(Object, ChannelPromise) to forward to the next ChannelOutboundHandler in the ChannelPipeline.

Methods inherited from class io.netty.channel.ChannelDuplexHandler

bind, close, connect, deregister, disconnect, flush, read

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

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

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, handlerAdded, handlerRemoved, isSharable

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

Constructor Detail

WebSocketServerExtensionHandler

public WebSocketServerExtensionHandler(WebSocketServerExtensionHandshaker... extensionHandshakers)

Constructor

Parameters:

extensionHandshakers - The extension handshaker in priority order. A handshaker could be repeated many times with fallback configuration.

Method Detail

channelRead

public void channelRead(ChannelHandlerContext ctx,
                        java.lang.Object msg)
                 throws java.lang.Exception

Description copied from class: ChannelInboundHandlerAdapter

Calls ChannelHandlerContext.fireChannelRead(Object) to forward to the next ChannelInboundHandler in the ChannelPipeline. Sub-classes may override this method to change behavior.

Specified by:

channelRead in interface ChannelInboundHandler

Overrides:

channelRead in class ChannelInboundHandlerAdapter

Throws:

java.lang.Exception

onHttpRequestChannelRead

protected void onHttpRequestChannelRead(ChannelHandlerContext ctx,
                                        HttpRequest request)
                                 throws java.lang.Exception

This is a method exposed to perform fail-fast checks of user-defined http types.

eg:
If the user has defined a specific HttpRequest type i.e.CustomHttpRequest and channelRead(io.netty.channel.ChannelHandlerContext, java.lang.Object) can receive LastHttpContent.EMPTY_LAST_CONTENT msg types too, can override it like this:

     public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
         if (msg != LastHttpContent.EMPTY_LAST_CONTENT) {
             if (msg instanceof CustomHttpRequest) {
                 onHttpRequestChannelRead(ctx, (CustomHttpRequest) msg);
             } else {
                 // if it's handling other HttpRequest types it MUST use onHttpRequestChannelRead again
                 // or have to delegate it to super.channelRead (that can perform redundant checks).
                 // If msg is not implementing HttpRequest, it can call ctx.fireChannelRead(msg) on it
                 // ...
                 super.channelRead(ctx, msg);
             }
         } else {
             // given that msg isn't a HttpRequest type we can just skip calling super.channelRead
             ctx.fireChannelRead(msg);
         }
     }
 

IMPORTANT: It already call super.channelRead(ctx, request) before returning.

Throws:

java.lang.Exception

write

public void write(ChannelHandlerContext ctx,
                  java.lang.Object msg,
                  ChannelPromise promise)
           throws java.lang.Exception

Description copied from class: ChannelDuplexHandler

Calls ChannelOutboundInvoker.write(Object, ChannelPromise) to forward to the next ChannelOutboundHandler in the ChannelPipeline. Sub-classes may override this method to change behavior.

Specified by:

write in interface ChannelOutboundHandler

Overrides:

write in class ChannelDuplexHandler

Parameters:

ctx - the ChannelHandlerContext for which the write operation is made

msg - the message to write

promise - the ChannelPromise to notify once the operation completes

Throws:

java.lang.Exception - thrown if an error occurs

onHttpResponseWrite

protected void onHttpResponseWrite(ChannelHandlerContext ctx,
                                   HttpResponse response,
                                   ChannelPromise promise)
                            throws java.lang.Exception

This is a method exposed to perform fail-fast checks of user-defined http types.

eg:
If the user has defined a specific HttpResponse type i.e.CustomHttpResponse and write(io.netty.channel.ChannelHandlerContext, java.lang.Object, io.netty.channel.ChannelPromise) can receive ByteBuf msg types too, it can be overridden like this:

     public void write(final ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
         if (msg != Unpooled.EMPTY_BUFFER && !(msg instanceof ByteBuf)) {
             if (msg instanceof CustomHttpResponse) {
                 onHttpResponseWrite(ctx, (CustomHttpResponse) msg, promise);
             } else {
                 // if it's handling other HttpResponse types it MUST use onHttpResponseWrite again
                 // or have to delegate it to super.write (that can perform redundant checks).
                 // If msg is not implementing HttpResponse, it can call ctx.write(msg, promise) on it
                 // ...
                 super.write(ctx, msg, promise);
             }
         } else {
             // given that msg isn't a HttpResponse type we can just skip calling super.write
             ctx.write(msg, promise);
         }
     }
 

IMPORTANT: It already call super.write(ctx, response, promise) before returning.

Throws:

java.lang.Exception