o /h_@sdZddlmZddlZddlmZmZddlmZm Z m Z ddl m Z ddl mZmZdd lmZdd lmZmZmZdd lmZmZerLdd lmZeeZd ZdZdZ dde!dDZ"dZ#d4ddZ$d5d d!Z%d6d%d&Z&d7d*d+Z'd8d.d/Z(Gd0d1d1Z)Gd2d3d3Z*dS)9zL Implements the HPACK header compression algorithm as detailed by RFC 7541. ) annotationsN) TYPE_CHECKINGAny)HPACKDecodingErrorInvalidTableSizeErrorOversizedHeaderListError)HuffmanEncoder) REQUEST_CODESREQUEST_CODES_LENGTH)decode_huffman) HeaderTupleHeaderWeaklyTypedNeverIndexedHeaderTuple) HeaderTabletable_entry_size)Iterable@cCsg|]}d|dqS)r).0irrD/var/www/html/govbot/env/lib/python3.10/site-packages/hpack/hpack.py sr iheaderrrawboolreturnr cCs@t|d}t|d}|s||d|dS|||S)zj Provides a header as a unicode string if raw is False, otherwise returns it as a bytestring. rrutf-8)bytes __class__decode)rrnamevaluerrr_unicode_if_needed#s   r'integerint prefix_bits bytearraycCstd|||dkrd|}t||dks|dkr%d|}t|t|}||kr2t|gS|g}||8}|dkrN||d@d|d L}|dks=||t|S) zi Encodes an integer according to the wacky integer encoding rules defined in the HPACK spec. zEncoding %d with %d bitsrz'Can only encode positive integers, got r)Prefix bits must be between 1 and 8, got )logdebug ValueError_PREFIX_BIT_MAX_NUMBERSr+append)r(r*msg max_numberelementsrrrencode_integer0s$    r9datar"tuple[int, int]c Cs|dks|dkrd|}t|t|}d}d}dd|?}z.|d|@}||krL ||}|d7}|dkr@||d|>7}n|||>7}n|d7}q+Wntyc} z d |}t|| d } ~ wwtd ||||fS) z Decodes an integer according to the wacky integer encoding rules defined in the HPACK spec. Returns a tuple of the decoded integer and the number of bytes that were consumed from ``data`` in order to get that integer. rr,r-rTr.r0z3Unable to decode HPACK integer representation from NzDecoded %d, consumed %d bytes)r3r4 IndexErrorrr1r2) r:r*r6r7indexshiftmasknumber next_byteerrrrrdecode_integerOs6      rD header_dictdict[bytes | str, bytes | str])Iterable[tuple[bytes | str, bytes | str]]ccsRt|tsdt|}t|t|ddd}|D] }|||fVqdS)z Converts a dictionary to an iterable of key-value tuples. This is a HPACK-specific function because it pulls "special-headers" out first and then emits them. zheader_dict not a dict, but cSst|d S)N:) _to_bytes startswith)krrrsz#_dict_to_iterable..)keyN) isinstancedicttype TypeErrorsortedkeys)rEr6rSrMrrr_dict_to_iterablevs rTr&bytes | str | AnycCs.t|}|tur |S|turt|}|dS)zB Convert anything to bytes through a UTF-8 encoded string r!)rPr"strencode)r&trrrrIs  rIc@s~eZdZdZd%ddZed&ddZejd'd dZ d(d)ddZd*d+ddZ d,ddZ d*d-ddZ d*d.d d!Z d/d"d#Z d$S)0Encoderzm An HPACK encoder object. This object takes HTTP headers and emits encoded HTTP/2 header blocks. r NonecCst|_ttt|_g|_dSN)r header_tabler r r huffman_codertable_size_changesselfrrr__init__s  zEncoder.__init__r)cC|jjSz> Controls the size of the HPACK header table. r\maxsizer_rrrheader_table_sizezEncoder.header_table_sizer&cCs$||j_|jjr|j|dSdSr[)r\reresizedr^r5r`r&rrrrfsTheadersIterable[HeaderTuple | tuple[bytes | str, bytes | str] | tuple[bytes | str, bytes | str, bool | None]] | dict[bytes | str, bytes | str]huffmanrr"c Csg}|jjr||d|j_t|trt|}n t|}|D].}d}t|tr0|j }n t |dkr:|d}t |dt |df}|| |||q"d |}td||S)a Takes a set of headers and encodes them into a HPACK-encoded header block. :param headers: The headers to encode. Must be either an iterable of tuples, an iterable of :class:`HeaderTuple `, or a ``dict``. If an iterable of tuples, the tuples may be either two-tuples or three-tuples. If they are two-tuples, the tuples must be of the format ``(name, value)``. If they are three-tuples, they must be of the format ``(name, value, sensitive)``, where ``sensitive`` is a boolean value indicating whether the header should be added to header tables anywhere. If not present, ``sensitive`` defaults to ``False``. If an iterable of :class:`HeaderTuple `, the tuples must always be two-tuples. Instead of using ``sensitive`` as a third tuple entry, use :class:`NeverIndexedHeaderTuple ` to request that the field never be indexed. .. warning:: HTTP/2 requires that all special headers (headers whose names begin with ``:`` characters) appear at the *start* of the header block. While this method will ensure that happens for ``dict`` subclasses, callers using any other iterable of tuples **must** ensure they place their special headers at the start of the iterable. For efficiency reasons users should prefer to use iterables of two-tuples: fixing the ordering of dictionary headers is an expensive operation that should be avoided if possible. :param huffman: (optional) Whether to Huffman-encode any header sent as a literal value. Except for use when debugging, it is recommended that this be left enabled. :returns: A bytestring containing the HPACK-encoded header block. FrrrzEncoded header block to %s)r\rhr5_encode_table_size_changerNrOrTiterr indexablelenrIaddjoinr1r2) r`rjrl header_block hpack_headersr sensitive new_headerencodedrrrrWs&8       zEncoder.encodeFto_addtuple[bytes, bytes]rvc Cstd||||\}}|stnt}|j||}|dur0|||||}|s.|j|||S|\} }} | r>|| }|S| | |||}|sO|j|||S)z6 Serializes a header key-value tuple. z7Adding %s to the header table, sensitive:%s, huffman:%sN) r1r2INDEX_INCREMENTAL INDEX_NEVERr\search_encode_literalrr_encode_indexed_encode_indexed_literal) r`ryrvrlr%r&indexbitmatchrxr>perfectrrrrrs0    z Encoder.addr>cCs"t|d}|ddO<t|S)zD Encodes a header using the indexed representation. r0rr.)r9r")r`r>fieldrrrrMs zEncoder._encode_indexedr%rcCsx|r|j|}|j|}tt|d}tt|d}|r.|ddO<|ddO<d|t||t||gS)z Encodes a header with a literal name and literal value. If ``indexing`` is True, the header will be added to the header table: otherwise it will not. r0rr.rm)r]rWr9rqrsr")r`r%r&rrlname_len value_lenrrrr~Us  zEncoder._encode_literalcCs||tkr t|d}nt|d}|dt|O<|r!|j|}tt|d}|r2|ddO<dt|t||gS)zv Encodes a header with an indexed name and a literal value and performs incremental indexing. rr0r.rm)r{r9ordr]rWrqrsr")r`r>r&rrlprefixrrrrrjs   zEncoder._encode_indexed_literalcCs@d}|jD]}t|d}|ddO<|t|7}qg|_|S)zd Produces the encoded form of all header table size change context updates. rmr )r^r9r")r`block size_bytesbrrrrns  z!Encoder._encode_table_size_changeNr rZr r)r&r)r rZ)T)rjrkrlrr r"F)ryrzrvrrlrr r")r>r)r r") r%r"r&r"rr"rlrr r") r>r)r&r"rr"rlrr r")r r")__name__ __module__ __qualname____doc__rapropertyrfsetterrWrrrr~rrnrrrrrYs    m 1  rYc@seZdZdZefd#ddZed$dd Zejd%d d Zd&d'ddZ d(ddZ d)ddZ d*ddZ d*ddZ d*ddZd+d d!Zd"S),Decodera  An HPACK decoder object. .. versionchanged:: 2.3.0 Added ``max_header_list_size`` argument. :param max_header_list_size: The maximum decompressed size we will allow for any single header block. This is a protection against DoS attacks that attempt to force the application to expand a relatively small amount of data into a really large header list, allowing enormous amounts of memory to be allocated. If this amount of data is exceeded, a `OversizedHeaderListError ` exception will be raised. At this point the connection should be shut down, as the HPACK state will no longer be usable. Defaults to 64kB. :type max_header_list_size: ``int`` max_header_list_sizer)r rZcCst|_||_|jj|_dSr[)rr\rremax_allowed_table_size)r`rrrrras zDecoder.__init__cCrbrcrdr_rrrrfrgzDecoder.header_table_sizer&cCs ||j_dSr[rdrirrrrfs Fr:r"rrIterable[HeaderTuple]c sntd|t|}g}t|}d}d}||kr||}t|d@} t|d@} t|d@} | r<|||d\} } n/| rJ|||d\} } n!| r`|rTd}t||||d} d} n | ||d\} } | r| | |t | d| d7}||j krd |j d }t ||| 7}||ks|z fd d |DWSty}zd }t||d}~ww)a Takes an HPACK-encoded header block and decodes it into a header set. :param data: A bytestring representing a complete HPACK-encoded header block. :param raw: (optional) Whether to return the headers as tuples of raw byte strings or to decode them as UTF-8 before returning them. The default value is False, which returns tuples of Unicode strings :returns: A list of two-tuples of ``(name, value)`` representing the HPACK-encoded headers, in the order they were decoded. :raises HPACKDecodingError: If an error is encountered while decoding the header block. z Decoding %srr.@rNz/Table size update not at the start of the blockrzA header list larger than z has been receivedcsg|]}t|qSr)r')rhrrrrsz"Decoder.decode..z!Unable to decode headers as UTF-8)r1r2 memoryviewrqr_decode_indexed_decode_literal_indexr_update_encoding_context_decode_literal_no_indexr5rrr_assert_valid_table_sizeUnicodeDecodeError)r`r:rdata_memrjdata_len inflated_size current_indexcurrentindexed literal_indexencoding_updaterconsumedr6rCrrrr$s\            4 zDecoder.decodecCs|j|jkr d}t|dS)zs Check that the table size set by the encoder is lower than the maximum we expect to have. z3Encoder did not shrink table size to within the maxN)rfrr)r`r6rrrrs z Decoder._assert_valid_table_sizecCs.t|d\}}||jkrd}t|||_|S)zC Handles a byte that updates the encoding context. rz)Encoder exceeded max allowable table size)rDrrrf)r`r:new_sizerr6rrrr's  z Decoder._update_encoding_contexttuple[HeaderTuple, int]cCs4t|d\}}t|j|}td||||fS)zP Decodes a header represented using the indexed representation. r0zDecoded %s, consumed %d)rDr r\ get_by_indexr1r2)r`r:r>rrrrrr3szDecoder._decode_indexedcC|j|ddS)NF should_index_decode_literalr`r:rrrr<z Decoder._decode_literal_no_indexcCr)NTrrrrrrr?rzDecoder._decode_literal_indexrcCsvd}|r|dd@}d}d}n|d}|d@}d}t|d@}|r5t||\}} |j|d} | }d} n1|dd }t|d \} } || | | } t| | krVd } t| |dd @r`t| } | | d}|| | d }t|d \} } || | | } t| | krd } t| |dd @rt| } || | 7}|rt| | }nt| | }|r|j | | t d |||||fS)z> Decodes a header represented with a literal. r?rFrrNr0zTruncated header blockr.z/Decoded %s, total consumed %d bytes, indexed %s) rrDr\rrqrr rr rrr1r2)r`r:rtotal_consumed indexed_namer not_indexable high_byter>rr%lengthr6r&rrrrrBsX           zDecoder._decode_literalN)rr)r rZrrr)r:r"rrr rr)r:r"r r))r:r"r r)r:r"rrr r)rrrrDEFAULT_MAX_HEADER_LIST_SIZErarrfrr$rrrrrrrrrrrs    S r)rrrrr r )r(r)r*r)r r+)r:r"r*r)r r;)rErFr rG)r&rUr r")+r __future__rloggingtypingrr exceptionsrrrrlr huffman_constantsr r huffman_tabler structr rrtablerrcollections.abcr getLoggerrr1 INDEX_NONEr|r{ranger4rr'r9rDrTrIrYrrrrrs4        '  z