Safe Haskell	None
Language	Haskell2010

Network.HPACK

Contents

Encoding and decoding
Encoding in a buffer
DynamicTable
Strategy for encoding
Errors
Headers
Basic types

Description

HPACK(https://tools.ietf.org/html/rfc7541) encoding and decoding a header list.

Synopsis

Encoding and decoding

encodeHeader Source

Arguments

:: EncodeStrategy
-> Size	The size of a temporary buffer.
-> DynamicTable
-> HeaderList
-> IO ByteString	An HPACK format

Converting HeaderList to the HPACK format. BufferOverrun will be thrown if the temporary buffer is too small.

decodeHeader Source

Arguments

:: DynamicTable
-> ByteString	An HPACK format
-> IO HeaderList

Converting the HPACK format to HeaderList. DecodeError would be thrown if the HPACK format is broken. BufferOverrun will be thrown if the temporary buffer for Huffman decoding is too small.

Encoding in a buffer

encodeHeaderBuffer Source

Arguments

:: Buffer
-> BufferSize
-> EncodeStrategy
-> Bool	`True` at the first time, `False` when continued.
-> DynamicTable
-> HeaderList
-> IO (HeaderList, Int)	Leftover `HeaderList` and the number of filled bytes.

Converting HeaderList to the HPACK format directly in the buffer.

4th argument is relating to dynamic table size update. When calling this function for a new HeaderList, it must be True. If True and set by setLimitForEncoding, dynamic table size update is generated at the beginning of the HPACK format.

If the buffer for encoding is small, leftover HeaderList will be returned. In this case, this function should be called with it again. 4th argument must be False.

DynamicTable

data DynamicTable Source

Type for dynamic table.

defaultDynamicTableSize :: Int Source

Default dynamic table size. The value is 4,096 bytes: an array has 128 entries.

>>> defaultDynamicTableSize
4096

newDynamicTableForEncoding Source

Arguments

:: Size	The dynamic table size
-> IO DynamicTable

Creating DynamicTable for encoding.

newDynamicTableForDecoding Source

Arguments

:: Size	The dynamic table size
-> Size	The size of temporary buffer for Huffman decoding
-> IO DynamicTable

Creating DynamicTable for decoding.

clearDynamicTable :: DynamicTable -> IO () Source

Clearing DynamicTable. Currently, this frees the temporary buffer for Huffman decoding.

withDynamicTableForEncoding Source

Arguments

:: Size	The dynamic table size
-> (DynamicTable -> IO a)
-> IO a

Creating DynamicTable for encoding, performing the action and clearing the DynamicTable.

withDynamicTableForDecoding Source

Arguments

:: Size	The dynamic table size
-> Size	The size of temporary buffer for Huffman
-> (DynamicTable -> IO a)
-> IO a

Creating DynamicTable for decoding, performing the action and clearing the DynamicTable.

setLimitForEncoding :: Size -> DynamicTable -> IO () Source

When SETTINGS_HEADER_TABLE_SIZE is received from a peer, its value should be set by this function.

Strategy for encoding

data CompressionAlgo Source

Compression algorithms for HPACK encoding.

Constructors

Naive	No compression
Static	Using indices in the static table only
Linear	Using indices

Instances

Eq CompressionAlgo Source
Show CompressionAlgo Source

data EncodeStrategy Source

Strategy for HPACK encoding.

Constructors

EncodeStrategy
Fields compressionAlgo :: !CompressionAlgo Which compression algorithm is used. useHuffman :: !Bool Whether or not to use Huffman encoding for strings.

Instances

Eq EncodeStrategy Source
Show EncodeStrategy Source

defaultEncodeStrategy :: EncodeStrategy Source

Default EncodeStrategy.

>>> defaultEncodeStrategy
EncodeStrategy {compressionAlgo = Linear, useHuffman = False}

Errors

data DecodeError Source

Errors for decoder.

Constructors

IndexOverrun Index	Index is out of range
EosInTheMiddle	Eos appears in the middle of huffman string
IllegalEos	Non-eos appears in the end of huffman string
TooLongEos	Eos of huffman string is more than 7 bits
EmptyEncodedString	Encoded string has no length
TooSmallTableSize	A peer set the dynamic table size less than 32
TooLargeTableSize	A peer tried to change the dynamic table size over the limit
IllegalTableSizeUpdate	Table size update at the non-beginning
HeaderBlockTruncated