U ʼbX@sdZddlZddlmZmZddlmZmZddlm Z m Z m Z ddl m Z ddlmZmZdd lmZdd lmZmZeeZd Zd Zd ZddedDZzeZWnek re e!fZYnXdZ"ddZ#ddZ$ddZ%ddZ&ddZ'Gddde(Z)Gddde(Z*dS) ze hpack/hpack ~~~~~~~~~~~ Implements the HPACK header compression algorithm as detailed by the IETF. N) HeaderTabletable_entry_size)to_byteto_bytes)HPACKDecodingErrorOversizedHeaderListErrorInvalidTableSizeError)HuffmanEncoder) REQUEST_CODESREQUEST_CODES_LENGTH)decode_huffman) HeaderTupleNeverIndexedHeaderTuple@cCsg|]}d|dqS)r).0irr//tmp/pip-unpacked-wheel-vloce9av/hpack/hpack.py sr icCs<t|d}t|d}|s0|d}|d}|||S)zj Provides a header as a unicode string if raw is False, otherwise returns it as a bytestring. rrutf-8)rdecode __class__)headerrawnamevaluerrr_unicode_if_needed,s     r!cCstd|||dkr"td||dks2|dkr>td|t|}||krXt|gS|g}||8}|dkr||d@d|d L}qf||t|Sd S) zn This encodes an integer according to the wacky integer encoding rules defined in the HPACK spec. zEncoding %d with %d bitsrz)Can only encode positive integers, got %sr+Prefix bits must be between 1 and 8, got %sN)logdebug ValueError_PREFIX_BIT_MAX_NUMBERS bytearrayappend)integer prefix_bits max_numberelementsrrrencode_integer9s&   r1cCs|dks|dkrtd|t|}d}d}dd|?}zbt|d|@}||krt||}|d7}|dkr||d|>7}n|||>7}q|d7}qRWn tk rtd|YnXtd ||||fS) z This decodes an integer according to the wacky integer encoding rules defined in the HPACK spec. Returns a tuple of the decoded integer and the number of bytes that were consumed from ``data`` in order to get that integer. rr"r#rr$r&z5Unable to decode HPACK integer representation from %rzDecoded %d, consumed %d bytes)r)r*r IndexErrorrr'r()datar.r/indexshiftmasknumberZ next_byterrrdecode_integer[s0    r9ccs>t|tstt|ddd}|D]}|||fVq&dS)z This converts a dictionary to an iterable of two-tuples. This is a HPACK-specific function becuase it pulls "special-headers" out first and then emits them. cSst|d S)N:) _to_bytes startswith)krrrz#_dict_to_iterable..)keyN) isinstancedictAssertionErrorsortedkeys)Z header_dictrEr@rrr_dict_to_iterablesrFcCs*t|tst|}t|tr |S|dS)z" Convert string to bytes. r)rA basestringstrbytesencode)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_tabler r r huffman_codertable_size_changesselfrrr__init__s zEncoder.__init__cCs|jjSz> Controls the size of the HPACK header table. rNmaxsizerQrrrheader_table_sizeszEncoder.header_table_sizecCs ||j_|jjr|j|dSrM)rNrVresizedrPr,rRr rrrrWsTcCstd|g}t|tr"t|}|jjr@||d|j_|D]\}d}t|t r`|j }nt |dkrt|d}t |dt |df}|| |||qDd|}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. zHPACK encoding %sFrrrr?zEncoded header block to %s)r'r(rArBrFrNrXr,_encode_table_size_changerZ indexablelenr;addjoin)rRheadershuffmanZ header_blockr sensitiverrrrJs$2       zEncoder.encodeFc Cstd||\}}|stnt}|j||}|dkr\|||||}|sX|j|||S|\} }} | rv|| }n"| | |||}|s|j|||S)zQ This function takes a header key-value tuple and serializes it. zAdding %s to the header tableN) r'r(INDEX_INCREMENTAL INDEX_NEVERrNsearch_encode_literalr\_encode_indexed_encode_indexed_literal) rRZto_addr`r_rr indexbitmatchencodedr5Zperfectrrrr\ s*    z Encoder.addcCs"t|d}|ddO<t|S)zD Encodes a header using the indexed representation. r&rr$)r1rI)rRr5fieldrrrre5s 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$r?)rOrJr1r[r]rI)rRrr rgr_name_len value_lenrrrrd=s  zEncoder._encode_literalcCs||tkrt|d}n t|d}|dt|O<|rB|j|}tt|d}|rd|ddO<dt|t||gS)zv Encodes a header with an indexed name and a literal value and performs incremental indexing. rr&r$r?)rar1ordrOrJr[r]rI)rRr5r rgr_prefixrlrrrrfRs   zEncoder._encode_indexed_literalcCs@d}|jD]*}t|d}|ddO<|t|7}q g|_|S)zd Produces the encoded form of all header table size change context updates. r?r )rPr1rI)rRblockZ size_bytesrrrrZhs  z!Encoder._encode_table_size_changeN)T)F)F)F)__name__ __module__ __qualname____doc__rSpropertyrWsetterrJr\rerdrfrZrrrrrLs   R ,  rLc@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 useable. Defaults to 64kB. :type max_header_list_size: ``int`` cCst|_||_|jj|_dSrM)rrNmax_header_list_sizerVmax_allowed_table_size)rRr{rrrrSs zDecoder.__init__cCs|jjSrTrUrQrrrrWszDecoder.header_table_sizecCs ||j_dSrMrUrYrrrrWsFcsdtd|t|}g}t|}d}d}||kr$t||}|d@rJdnd} |d@rZdnd} |d@rjdnd} | r|||d\} } nZ| r|||d\} } n>| r|rtd |||d} d} n| ||d\} } | r| | |t | 7}||j krt d |j || 7}q(|zfd d |DWStk r^td YnXdS)a Takes an HPACK-encoded header block and decodes it into a header set. :param data: A bytestring representing a complete HPACK-encoded header block. :param raw: (optional) Whether to return the headers as tuples of raw byte strings or to decode them as UTF-8 before returning them. The default value is False, which returns tuples of Unicode strings :returns: A list of two-tuples of ``(name, value)`` representing the HPACK-encoded headers, in the order they were decoded. :raises HPACKDecodingError: If an error is encountered while decoding the header block. z Decoding %srr$TF@rrNz/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[r_decode_indexed_decode_literal_indexr_update_encoding_context_decode_literal_no_indexr,rr{r_assert_valid_table_sizeUnicodeDecodeError)rRr4rZdata_memr^Zdata_lenZ inflated_sizeZ current_indexcurrentZindexedZ literal_indexZencoding_updaterconsumedrrrrs\           zDecoder.decodecCs|j|jkrtddS)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)rWr|r rQrrrrs z Decoder._assert_valid_table_sizecCs*t|d\}}||jkr td||_|S)zC Handles a byte that updates the encoding context. rqz)Encoder exceeded max allowable table size)r9r|r rW)rRr4Znew_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)r9rrN get_by_indexr'r()rRr4r5rrrrrrszDecoder._decode_indexedcCs ||dS)NF_decode_literalrRr4rrrr'sz Decoder._decode_literal_no_indexcCs ||dS)NTrrrrrr*szDecoder._decode_literal_indexcCsd}|r"t|dd@}d}d}n t|d}|d@}d}|d@}|rnt||\}} |j|d} | }d} nb|dd }t|d \} } || | | } t| | krtd t|dd @rt| } | | d}|| | d }t|d \} } || | | } t| | krtd t|dd @r.t| } || | 7}|rLt| | } n t| | } |rj|j | | t d | ||| |fS)z> Decodes a header represented with a literal. r?rnFrmrNr&zTruncated header blockr$z/Decoded %s, total consumed %d bytes, indexed %s) rr9rNrr[rr rrr\r'r()rRr4Z should_indexZtotal_consumedZ indexed_namerkZ not_indexableZ high_byter5rrlengthr rrrrr-sT       zDecoder._decode_literalN)F)rtrurvrwDEFAULT_MAX_HEADER_LIST_SIZErSrxrWryrrrrrrrrrrrrzvs    U   rz)+rwloggingtablerrcompatrr exceptionsrrr r_r Zhuffman_constantsr r Z huffman_tabler structrr getLoggerrtr'Z INDEX_NONErbraranger*rG NameErrorrHrIrr!r1r9rFr;objectrLrzrrrrs4    ") Z