Package com.linkedin.alpini.netty4.handlers

Class BasicHttpResponseDecoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.handler.codec.ByteToMessageDecoder

io.netty.handler.codec.http.HttpObjectDecoder

com.linkedin.alpini.netty4.handlers.BasicHttpResponseDecoder

All Implemented Interfaces:

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

public abstract class BasicHttpResponseDecoder
extends io.netty.handler.codec.http.HttpObjectDecoder

Decodes ByteBufs into HttpResponses and HttpContents.

Parameters that prevents excessive memory consumption

Name	Meaning
maxInitialLineLength	The maximum length of the initial line (e.g. "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 exceeds this value, the transfer encoding of the decoded response will be converted to 'chunked' and the content will be split into multiple HttpContents. If the transfer encoding of the HTTP response is 'chunked' already, each chunk will be split into smaller chunks if the length of the chunk exceeds this value. If you prefer not to handle HttpContents in your handler, insert HttpObjectAggregator after this decoder in the ChannelPipeline.

Decoding a response for a HEAD request

Unlike other HTTP requests, the successful response of a HEAD request does not have any content even if there is Content-Length header. Because BasicHttpResponseDecoder is not able to determine if the response currently being decoded is associated with a HEAD request, you must override HttpObjectDecoder.isContentAlwaysEmpty(HttpMessage) to return true for the response of the HEAD request.

If you are writing an HTTP client that issues a HEAD request, please use BasicHttpClientCodec instead of this decoder. It will perform additional state management to handle the responses for HEAD requests correctly.

Decoding a response for a CONNECT request

You also need to do additional state management to handle the response of a CONNECT request properly, like you did for HEAD. One difference is that the decoder should stop decoding completely after decoding the successful 200 response since the connection is not an HTTP connection anymore.

BasicHttpClientCodec also handles this edge case correctly, so you have to use BasicHttpClientCodec if you are writing an HTTP client that issues a CONNECT request.

Nested Class Summary

Nested classes/interfaces inherited from class io.netty.handler.codec.ByteToMessageDecoder

io.netty.handler.codec.ByteToMessageDecoder.Cumulator

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

io.netty.channel.ChannelHandler.Sharable

Field Summary

Fields inherited from class io.netty.handler.codec.http.HttpObjectDecoder

DEFAULT_ALLOW_DUPLICATE_CONTENT_LENGTHS, DEFAULT_CHUNKED_SUPPORTED, DEFAULT_INITIAL_BUFFER_SIZE, DEFAULT_MAX_CHUNK_SIZE, DEFAULT_MAX_HEADER_SIZE, DEFAULT_MAX_INITIAL_LINE_LENGTH, DEFAULT_VALIDATE_HEADERS, validateHeaders

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

COMPOSITE_CUMULATOR, MERGE_CUMULATOR

Constructor Summary

Constructors

Constructor	Description
BasicHttpResponseDecoder()	Creates a new instance with the default maxInitialLineLength (4096), maxHeaderSize (8192), and maxChunkSize (8192).
BasicHttpResponseDecoder(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize)	Creates a new instance with the specified parameters.
BasicHttpResponseDecoder(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean validateHeaders)
BasicHttpResponseDecoder(int maxInitialLineLength, int maxHeaderSize, int maxChunkSize, boolean validateHeaders, int initialBufferSize)

Method Summary

Modifier and Type	Method	Description
protected abstract io.netty.handler.codec.http.HttpResponse	checkLastResponse(io.netty.handler.codec.http.HttpResponse response)
protected io.netty.handler.codec.http.HttpMessage	createInvalidMessage()
protected io.netty.handler.codec.http.HttpMessage	createMessage(java.lang.String[] initialLine)
protected boolean	isDecodingRequest()
protected abstract io.netty.handler.codec.http.HttpRequest	lastRequest()

Methods inherited from class io.netty.handler.codec.http.HttpObjectDecoder

decode, decodeLast, handleTransferEncodingChunkedWithContentLength, isContentAlwaysEmpty, isSwitchingToNonHttp1Protocol, reset, userEventTriggered

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

actualReadableBytes, callDecode, channelInactive, channelRead, channelReadComplete, discardSomeReadBytes, handlerRemoved, handlerRemoved0, internalBuffer, isSingleDecode, setCumulator, setDiscardAfterReads, setSingleDecode

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, handlerAdded, 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

Constructor Detail

BasicHttpResponseDecoder

public BasicHttpResponseDecoder()

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

BasicHttpResponseDecoder

public BasicHttpResponseDecoder(int maxInitialLineLength,
                                int maxHeaderSize,
                                int maxChunkSize)

Creates a new instance with the specified parameters.

BasicHttpResponseDecoder

public BasicHttpResponseDecoder(int maxInitialLineLength,
                                int maxHeaderSize,
                                int maxChunkSize,
                                boolean validateHeaders)

BasicHttpResponseDecoder

public BasicHttpResponseDecoder(int maxInitialLineLength,
                                int maxHeaderSize,
                                int maxChunkSize,
                                boolean validateHeaders,
                                int initialBufferSize)

Method Detail

createMessage

protected io.netty.handler.codec.http.HttpMessage createMessage(java.lang.String[] initialLine)

Specified by:

createMessage in class io.netty.handler.codec.http.HttpObjectDecoder

createInvalidMessage

protected io.netty.handler.codec.http.HttpMessage createInvalidMessage()

Specified by:

createInvalidMessage in class io.netty.handler.codec.http.HttpObjectDecoder

isDecodingRequest

protected boolean isDecodingRequest()

Specified by:

isDecodingRequest in class io.netty.handler.codec.http.HttpObjectDecoder

lastRequest

protected abstract io.netty.handler.codec.http.HttpRequest lastRequest()

checkLastResponse

protected abstract io.netty.handler.codec.http.HttpResponse checkLastResponse(io.netty.handler.codec.http.HttpResponse response)