txt: ## dist_zef-raku-community-modules-HTTP-HPACK.md
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  # NAME
  
  HTTP::HPACK - Implementation of RFC 7541 HPACK: Header Compression for HTTP/2
  
  # SYNOPSIS
  
  ```
  use HTTP::HPACK;
  
  # Decoding:
  my $decoder = HTTP::HPACK::Decoder.new;
  my @headers = $decoder.decode-headers($buf);
  say "{.name}: {.value} ({.indexing})" for @headers;
  
  # Encoding:
  my @headers = 
    HTTP::HPACK::Header.new(
      name  => ':method',
      value => 'GET'
    ),
    HTTP::HPACK::Header.new(
      name     => 'password',
      value    => 'correcthorsebatterystaple',
      indexing => HTTP::HPACK::Indexing::NeverIndexed
    );
  my $encoder = HTTP::HPACK::Encoder.new;
  my $buf = $encoder.encode-headers(@headers);
  
  ```
  
  # DESCRIPTION
  
  HPACK is the HTTP/2 header compression algorithm. This module implements encoding (compression) and decoding (decompression) of the HPACK format, as specified in RFC 7541. A HTTP/2 connection will typically have an instance of the decoder (to decompress incoming headers) and an instance of the encoder (to compress outgoing headers).
  
  # Notes on specific features
  
  ## Huffman compression
  
  Decoding of headers compressed using the Huffman codes (set out in the RFC) takes place automatically. By default, the encoder will not apply Huffman compression. To enable this, construct it with the `huffman` named argument set to `True`:
  
  ```
  my $encoder = HTTP::HPACK::Encoder.new(:huffman);
  
  ```
  
  ## Dynamic table management
  
  The dynamic table size can be limited by passing the `dynamic-table-limit` named argument when constructing either the encoder or decoder:
  
  ```
  my $decoder = HTTP::HPACK::Decoder.new(dynamic-table-limit => 256);
  
  ```
  
  It is also possible to introspect the current dynamic table size:
  
  ```
  say $decoder.dynamic-table-size;
  
  ```
  
  The size is computed according to the algorithm in RFC 7541 Section 4.1.
  
  # Thread safety
  
  Instances of HTTP::HPACK::Header are immutable and so safe to share and access concurrently. Instances of `HTTP::HPACK::Decoder` and `HTTP::HPACK::Encoder` are stateful (as a result of the dynamic table), and so a given instance may not be used concurrently. This is not a practical problem, since headers may only be processed in the order they are being received or transmitted anyway.
  
  # Known issues
  
  * The Huffman code termination handling has not been validated to be completely up to specification, and so may fail to signal errors in some cases where the Huffman code is terminated in a bogus way.
  
  # AUTHOR
  
  Jonathan Worthington
  
  # COPYRIGHT AND LICENSE
  
  Copyright 2016 - 2023 Jonathan Worthington
  
  Copyright 2024 - 2025 Raku Community
  
  This library is free software; you can redistribute it and/or modify it under the Artistic License 2.0.
  