io.netty.handler.codec.http

Class HttpObjectDecoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelStateHandlerAdapter

io.netty.channel.ChannelInboundByteHandlerAdapter

io.netty.handler.codec.ByteToMessageDecoder

io.netty.handler.codec.ReplayingDecoder<io.netty.handler.codec.http.HttpObjectDecoder.State>

io.netty.handler.codec.http.HttpObjectDecoder

All Implemented Interfaces:

ChannelHandler, ChannelInboundByteHandler, ChannelStateHandler

Direct Known Subclasses:

HttpRequestDecoder, HttpResponseDecoder, RtspObjectDecoder

public abstract class HttpObjectDecoder
extends ReplayingDecoder<io.netty.handler.codec.http.HttpObjectDecoder.State>

Decodes ByteBufs into HttpMessages and HttpContents.

Parameters that prevents excessive memory consumption

Name	Meaning
maxInitialLineLength	The maximum length of the initial line (e.g. "GET / HTTP/1.0" or "HTTP/1.0 200 OK") If the length of the initial line exceeds this value, a TooLongFrameException will be raised.
maxHeaderSize	The maximum length of all headers. If the sum of the length of each header exceeds this value, a TooLongFrameException will be raised.
maxChunkSize	The maximum length of the content or each chunk. If the content length (or the length of each chunk) exceeds this value, the content or chunk will be split into multiple HttpContents whose length is maxChunkSize at maximum.

Chunked Content

If the content of an HTTP message is greater than maxChunkSize or the transfer encoding of the HTTP message is 'chunked', this decoder generates one HttpMessage instance and its following HttpContents per single HTTP message to avoid excessive memory consumption. For example, the following HTTP message:

 GET / HTTP/1.1
 Transfer-Encoding: chunked

 1a
 abcdefghijklmnopqrstuvwxyz
 10
 1234567890abcdef
 0
 Content-MD5: ...
 [blank line]
 

triggers HttpRequestDecoder to generate 3 objects:

1. An HttpRequest,
2. The first HttpContent whose content is 'abcdefghijklmnopqrstuvwxyz',
3. The second LastHttpContent whose content is '1234567890abcdef', which marks the end of the content.

If you prefer not to handle HttpContents by yourself for your convenience, insert HttpObjectAggregator after this decoder in the ChannelPipeline. However, please note that your server might not be as memory efficient as without the aggregator.

Extensibility

Please note that this decoder is designed to be extended to implement a protocol derived from HTTP, such as RTSP and ICAP. To implement the decoder of such a derived protocol, extend this class and implement all abstract methods properly.

Nested Class Summary

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

ChannelHandler.Sharable

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	HttpObjectDecoder() Creates a new instance with the default maxInitialLineLength (4096}, maxHeaderSize (8192), and maxChunkSize (8192).
protected	HttpObjectDecoder(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean chunkedSupported) Creates a new instance with the specified parameters.

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract HttpMessage	createInvalidMessage()
protected abstract HttpMessage	createMessage(String[] initialLine)
protected Object	decode(ChannelHandlerContext ctx, ByteBuf buffer) Decode the from one ByteBuf to an other.
protected boolean	isContentAlwaysEmpty(HttpMessage msg)
protected abstract boolean	isDecodingRequest()

Methods inherited from class io.netty.handler.codec.ReplayingDecoder

actualReadableBytes, callDecode, channelInactive, channelReadSuspended, checkpoint, checkpoint, discardInboundReadBytes, discardInboundReadBytes0, internalBuffer, newInboundBuffer, newInboundBuffer0, state, state

Methods inherited from class io.netty.handler.codec.ByteToMessageDecoder

decodeLast, inboundBufferUpdated, isSingleDecode, setSingleDecode

Methods inherited from class io.netty.channel.ChannelInboundByteHandlerAdapter

freeInboundBuffer, inboundBufferUpdated

Methods inherited from class io.netty.channel.ChannelStateHandlerAdapter

channelActive, channelRegistered, channelUnregistered, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

afterAdd, afterRemove, beforeAdd, beforeRemove, exceptionCaught

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.ChannelStateHandler

channelActive, channelRegistered, channelUnregistered, userEventTriggered

Methods inherited from interface io.netty.channel.ChannelHandler

afterAdd, afterRemove, beforeAdd, beforeRemove, exceptionCaught

Constructor Detail

HttpObjectDecoder

protected HttpObjectDecoder()

Creates a new instance with the default maxInitialLineLength (4096}, maxHeaderSize (8192), and maxChunkSize (8192).

HttpObjectDecoder

protected HttpObjectDecoder(int maxInitialLineLength,
                 int maxHeaderSize,
                 int maxChunkSize,
                 boolean chunkedSupported)

Creates a new instance with the specified parameters.

Method Detail

decode

protected Object decode(ChannelHandlerContext ctx,
            ByteBuf buffer)
                 throws Exception

Description copied from class: ByteToMessageDecoder

Decode the from one ByteBuf to an other. This method will be called till either the input ByteBuf has nothing to read anymore, till nothing was read from the input ByteBuf or till this method returns null.

Specified by:

decode in class ByteToMessageDecoder

Parameters:

ctx - the ChannelHandlerContext which this ByteToByteDecoder belongs to

buffer - the ByteBuf from which to read data

Returns:

message the message to which the content of the ByteBuf was decoded, or null if there was not enough data left in the ByteBuf to decode.

Throws:

Exception - is thrown if an error accour

isContentAlwaysEmpty

protected boolean isContentAlwaysEmpty(HttpMessage msg)

isDecodingRequest

protected abstract boolean isDecodingRequest()

createMessage

protected abstract HttpMessage createMessage(String[] initialLine)
                                      throws Exception

Throws:

Exception

createInvalidMessage

protected abstract HttpMessage createInvalidMessage()