HPACK

Header Compression for HTTP/2

Download

HPACK can be downloaded from the Maven central repository. Add the following dependency section to your pom.xml file:

<dependency>
    <groupId>com.twitter</groupId>
    <artifactId>hpack</artifactId>
    <version>1.0.1</version>
</dependency>

Getting Started

This library provides support for compression of header lists into header blocks. The following code fragment demonstrates the use of Encoder and Decoder:

try {
  int maxHeaderSize = 4096;
  int maxHeaderTableSize = 4096;
  byte[] name = "name".getBytes();
  byte[] value = "value".getBytes();
  boolean sensitive = false;

  ByteArrayOutputStream out = new ByteArrayOutputStream();

  // encode header list into header block
  Encoder encoder = new Encoder(maxHeaderTableSize);
  encoder.encodeHeader(out, name, value, sensitive);

  ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());

  HeaderListener listener = new HeaderListener() {
    @Override
    public void addHeader(byte[] name, byte[] value, boolean sensitive) {
      // handle header field
    }
  };

  // decode header list from header block
  Decoder decoder = new Decoder(maxHeaderSize, maxHeaderTableSize);
  decoder.decode(in, listener);
  decoder.endHeaderBlock();
} catch (IOException e) {
  // handle exception
}

Problems?

If you find any issues please report them or better, send a pull request.

Authors

• Jeff Pinner https://twitter.com/jpinner
• Bill Gallagher https://twitter.com/billjgallagher

License

Copyright 2013 Twitter, Inc.

Licensed under the Apache License, Version 2.0: http://www.apache.org/licenses/LICENSE-2.0