Package org.jboss.netty.handler.codec.http

Class HttpMessageDecoder

  • All Implemented Interfaces:
    ChannelHandler, ChannelUpstreamHandler, LifeCycleAwareChannelHandler
    Direct Known Subclasses:
    HttpRequestDecoder, HttpResponseDecoder, RtspMessageDecoder
    public abstract class HttpMessageDecoder
extends ReplayingDecoder<HttpMessageDecoder.State>
    Decodes ChannelBuffers into HttpMessages and HttpChunks.

    Parameters that prevents excessive memory consumption

    NameMeaning
    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 HttpChunks 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 HttpChunks 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 4 objects:
    1. An HttpRequest whose chunked property is true,
    2. The first HttpChunk whose content is 'abcdefghijklmnopqrstuvwxyz',
    3. The second HttpChunk whose content is '1234567890abcdef', and
    4. An HttpChunkTrailer which marks the end of the content.
    If you prefer not to handle HttpChunks by yourself for your convenience, insert HttpChunkAggregator 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.

    • Constructor Detail

      • HttpMessageDecoder

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

      • HttpMessageDecoder

        protected HttpMessageDecoder​(int maxInitialLineLength,
                             int maxHeaderSize,
                             int maxChunkSize)
        Creates a new instance with the specified parameters.