o .jW@sdZddlmZddlZddlmZmZmZddlm Z ddl m Z m Z ddl mZdd lmZmZdd lmZmZeeZd Zd Zd ZddedDZeefZdZ ddZ!ddZ"ddZ#ddZ$ddZ%GdddZ&GdddZ'dS) ze hpack/hpack ~~~~~~~~~~~ Implements the HPACK header compression algorithm as detailed by the IETF. ) annotationsN)HPACKDecodingErrorInvalidTableSizeErrorOversizedHeaderListError)HuffmanEncoder) REQUEST_CODESREQUEST_CODES_LENGTH)decode_huffman) HeaderTupleNeverIndexedHeaderTuple) HeaderTabletable_entry_size@cCsg|]}d|dqS)r).0irrD/home/thesage/.local/lib/python3.10/site-packages/jh2/hpack/hpack.py sr icCs<t|d}t|d}|s|d}|d}|||S)zj Provides a header as a unicode string if raw is False, otherwise returns it as a bytestring. rrutf-8)bytesdecode __class__)headerrawnamevaluerrr_unicode_if_needed*s     r!cCstd|||dkrtd||dks|dkrtd|t|}||kr,t|gS|g}||8}|dkrH||d@d|d L}|dks7||t|S) zn This encodes an integer according to the wacky integer encoding rules defined in the HPACK spec. zEncoding %d with %d bitsrz)Can only encode positive integers, got %sr+Prefix bits must be between 1 and 8, got %s)logdebug ValueError_PREFIX_BIT_MAX_NUMBERS bytearrayappend)integer prefix_bits max_numberelementsrrrencode_integer7s     r1cCs|dks|dkrtd|t|}d}d}dd|?}z.|d|@}||krI ||}|d7}|dkr=||d|>7}n|||>7}n|d7}q(Wn tyWtd |wtd ||||fS) z This decodes an integer according to the wacky integer encoding rules defined in the HPACK spec. Returns a tuple of the decoded integer and the number of bytes that were consumed from ``data`` in order to get that integer. rr"r#rTr$r&z5Unable to decode HPACK integer representation from %rzDecoded %d, consumed %d bytes)r)r* IndexErrorrr'r()datar.r/indexshiftmasknumber next_byterrrdecode_integerUs4     r:ccs@t|tsJt|ddd}|D] }|||fVqdS)z This converts a dictionary to an iterable of two-tuples. This is a HPACK-specific function because it pulls "special-headers" out first and then emits them. cSst|d S)N:) _to_bytes startswith)krrrsz#_dict_to_iterable..)keyN) isinstancedictsortedkeys) header_dictrDr@rrr_dict_to_iterable|s rFcCs*t|ts t|}t|tr|S|dS)z" Convert string to bytes. r)rA basestringstrrencode)stringrrrr<s r<c@sjeZdZdZddZeddZejddZddd Zdd d Z d dZ dddZ dddZ ddZ dS)Encoderzm An HPACK encoder object. This object takes HTTP headers and emits encoded HTTP/2 header blocks. cCst|_ttt|_g|_dSN)r header_tablerrr huffman_codertable_size_changesselfrrr__init__s  zEncoder.__init__cC|jjSz> Controls the size of the HPACK header table. rMmaxsizerPrrrheader_table_sizezEncoder.header_table_sizecCs$||j_|jjr|j|dSdSrL)rMrVresizedrOr,rQr rrrrWsTcCsg}t|tr t|}|jjr||d|j_|D].}d}t|tr*|j }n t |dkr4|d}t |dt |df}|| |||qd |}t d||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)rArBrFrMrYr,_encode_table_size_changer indexablelenr<addjoinr'r()rQheadershuffman header_blockr sensitiverrrrIs"2      zEncoder.encodeFc Cstd||||\}}|stnt}|j||}|dur0|||||}|s.|j|||S|\} }} | r>|| }|S| | |||}|sO|j|||S)zQ This function takes a header key-value tuple and serializes it. z7Adding %s to the header table, sensitive:%s, huffman:%sN) r'r(INDEX_INCREMENTAL INDEX_NEVERrMsearch_encode_literalr__encode_indexed_encode_indexed_literal) rQto_addrdrbrr indexbitmatchencodedr5perfectrrrr_s,    z Encoder.addcCs"t|d}|ddO<t|S)zD Encodes a header using the indexed representation. r&rr$)r1r)rQr5fieldrrrri*s zEncoder._encode_indexedcCsx|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. r&rr$r[)rNrIr1r^r`r)rQrr rlrbname_len value_lenrrrrh2s  zEncoder._encode_literalcCs||tkr t|d}nt|d}|dt|O<|r!|j|}tt|d}|r2|ddO<dt|t||gS)zv Encodes a header with an indexed name and a literal value and performs incremental indexing. rr&r$r[)rer1ordrNrIr^r`r)rQr5r rlrbprefixrrrrrrjEs   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. r[r )rOr1r)rQblock size_bytesrrrr\[s  z!Encoder._encode_table_size_changeN)TF)__name__ __module__ __qualname____doc__rRpropertyrWsetterrIr_rirhrjr\rrrrrKs    Q/   rKc@speZdZdZefddZeddZejddZddd Z d d Z d d Z ddZ ddZ ddZddZdS)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`` cCst|_||_|jj|_dSrL)r rMmax_header_list_sizerVmax_allowed_table_size)rQrrrrrRs zDecoder.__init__cCrSrTrUrPrrrrWrXzDecoder.header_table_sizecCs ||j_dSrLrUrZrrrrWs FcsTtd|t|}g}t|}d}d}||kr||}|d@r"dnd} |d@r*dnd} |d@r2dnd} | rB|||d\} } n-| rP|||d\} } n| rd|rXtd |||d} d} n |||d\} } | r| | |t | 7}||j krt d |j || 7}||ks| z fd d |DWStytd w)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$TF@rxNz/Table size update not at the start of the blockz.A header list larger than %d has been receivedcsg|]}t|qSr)r!)rhrrrrsz"Decoder.decode..z"Unable to decode headers as UTF-8.)r'r( memoryviewr^_decode_indexed_decode_literal_indexr_update_encoding_context_decode_literal_no_indexr,rrr_assert_valid_table_sizeUnicodeDecodeError)rQr4rdata_memradata_len inflated_size current_indexcurrentindexed literal_indexencoding_updaterconsumedrrrrsT     1 zDecoder.decodecCs|j|jkr tddS)zs Check that the table size set by the encoder is lower than the maximum we expect to have. z3Encoder did not shrink table size to within the maxN)rWrrrPrrrrs z Decoder._assert_valid_table_sizecCs*t|d\}}||jkrtd||_|S)zC Handles a byte that updates the encoding context. rwz)Encoder exceeded max allowable table size)r:rrrW)rQr4new_sizerrrrrs  z Decoder._update_encoding_contextcCs4t|d\}}t|j|}td||||fS)zP Decodes a header represented using the indexed representation. r&zDecoded %s, consumed %d)r:r rM get_by_indexr'r()rQr4r5rrrrrr szDecoder._decode_indexedcC ||dS)NF_decode_literalrQr4rrrr z Decoder._decode_literal_no_indexcCr)NTrrrrrrrzDecoder._decode_literal_indexcCsjd}|r|dd@}d}d}n|d}|d@}d}|d@}|r3t||\}} |j|d} | }d} n/|dd }t|d \} } || | | } t| | krRtd |dd @r\t| } | | d}|| | d }t|d \} } || | | } t| | krtd |dd @rt| } || | 7}|rt| | } nt| | } |r|j| | t d | ||| |fS)z> Decodes a header represented with a literal. r?rtFrsrNr&zTruncated header blockr$z/Decoded %s, total consumed %d bytes, indexed %s) r:rMrr^rr r r r_r'r()rQr4 should_indextotal_consumed indexed_namerq not_indexable high_byter5rrlengthr rrrrrsT          zDecoder._decode_literalNr{)r|r}r~rDEFAULT_MAX_HEADER_LIST_SIZErRrrWrrrrrrrrrrrrris    O    r)(r __future__rlogging exceptionsrrrrbrhuffman_constantsrr huffman_tabler structr r tabler r getLoggerr|r' INDEX_NONErfreranger*rHrrGrr!r1r:rFr<rKrrrrrs0     '  X