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Diffstat (limited to 'venv/lib/python3.11/site-packages/h11/_readers.py')
| -rw-r--r-- | venv/lib/python3.11/site-packages/h11/_readers.py | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/venv/lib/python3.11/site-packages/h11/_readers.py b/venv/lib/python3.11/site-packages/h11/_readers.py new file mode 100644 index 0000000..08a9574 --- /dev/null +++ b/venv/lib/python3.11/site-packages/h11/_readers.py @@ -0,0 +1,247 @@ +# Code to read HTTP data +# +# Strategy: each reader is a callable which takes a ReceiveBuffer object, and +# either: +# 1) consumes some of it and returns an Event +# 2) raises a LocalProtocolError (for consistency -- e.g. we call validate() +# and it might raise a LocalProtocolError, so simpler just to always use +# this) +# 3) returns None, meaning "I need more data" +# +# If they have a .read_eof attribute, then this will be called if an EOF is +# received -- but this is optional. Either way, the actual ConnectionClosed +# event will be generated afterwards. +# +# READERS is a dict describing how to pick a reader. It maps states to either: +# - a reader +# - or, for body readers, a dict of per-framing reader factories + +import re +from typing import Any, Callable, Dict, Iterable, NoReturn, Optional, Tuple, Type, Union + +from ._abnf import chunk_header, header_field, request_line, status_line +from ._events import Data, EndOfMessage, InformationalResponse, Request, Response +from ._receivebuffer import ReceiveBuffer +from ._state import ( + CLIENT, + CLOSED, + DONE, + IDLE, + MUST_CLOSE, + SEND_BODY, + SEND_RESPONSE, + SERVER, +) +from ._util import LocalProtocolError, RemoteProtocolError, Sentinel, validate + +__all__ = ["READERS"] + +header_field_re = re.compile(header_field.encode("ascii")) +obs_fold_re = re.compile(rb"[ \t]+") + + +def _obsolete_line_fold(lines: Iterable[bytes]) -> Iterable[bytes]: + it = iter(lines) + last: Optional[bytes] = None + for line in it: + match = obs_fold_re.match(line) + if match: + if last is None: + raise LocalProtocolError("continuation line at start of headers") + if not isinstance(last, bytearray): + # Cast to a mutable type, avoiding copy on append to ensure O(n) time + last = bytearray(last) + last += b" " + last += line[match.end() :] + else: + if last is not None: + yield last + last = line + if last is not None: + yield last + + +def _decode_header_lines( + lines: Iterable[bytes], +) -> Iterable[Tuple[bytes, bytes]]: + for line in _obsolete_line_fold(lines): + matches = validate(header_field_re, line, "illegal header line: {!r}", line) + yield (matches["field_name"], matches["field_value"]) + + +request_line_re = re.compile(request_line.encode("ascii")) + + +def maybe_read_from_IDLE_client(buf: ReceiveBuffer) -> Optional[Request]: + lines = buf.maybe_extract_lines() + if lines is None: + if buf.is_next_line_obviously_invalid_request_line(): + raise LocalProtocolError("illegal request line") + return None + if not lines: + raise LocalProtocolError("no request line received") + matches = validate( + request_line_re, lines[0], "illegal request line: {!r}", lines[0] + ) + return Request( + headers=list(_decode_header_lines(lines[1:])), _parsed=True, **matches + ) + + +status_line_re = re.compile(status_line.encode("ascii")) + + +def maybe_read_from_SEND_RESPONSE_server( + buf: ReceiveBuffer, +) -> Union[InformationalResponse, Response, None]: + lines = buf.maybe_extract_lines() + if lines is None: + if buf.is_next_line_obviously_invalid_request_line(): + raise LocalProtocolError("illegal request line") + return None + if not lines: + raise LocalProtocolError("no response line received") + matches = validate(status_line_re, lines[0], "illegal status line: {!r}", lines[0]) + http_version = ( + b"1.1" if matches["http_version"] is None else matches["http_version"] + ) + reason = b"" if matches["reason"] is None else matches["reason"] + status_code = int(matches["status_code"]) + class_: Union[Type[InformationalResponse], Type[Response]] = ( + InformationalResponse if status_code < 200 else Response + ) + return class_( + headers=list(_decode_header_lines(lines[1:])), + _parsed=True, + status_code=status_code, + reason=reason, + http_version=http_version, + ) + + +class ContentLengthReader: + def __init__(self, length: int) -> None: + self._length = length + self._remaining = length + + def __call__(self, buf: ReceiveBuffer) -> Union[Data, EndOfMessage, None]: + if self._remaining == 0: + return EndOfMessage() + data = buf.maybe_extract_at_most(self._remaining) + if data is None: + return None + self._remaining -= len(data) + return Data(data=data) + + def read_eof(self) -> NoReturn: + raise RemoteProtocolError( + "peer closed connection without sending complete message body " + "(received {} bytes, expected {})".format( + self._length - self._remaining, self._length + ) + ) + + +chunk_header_re = re.compile(chunk_header.encode("ascii")) + + +class ChunkedReader: + def __init__(self) -> None: + self._bytes_in_chunk = 0 + # After reading a chunk, we have to throw away the trailing \r\n; if + # this is >0 then we discard that many bytes before resuming regular + # de-chunkification. + self._bytes_to_discard = 0 + self._reading_trailer = False + + def __call__(self, buf: ReceiveBuffer) -> Union[Data, EndOfMessage, None]: + if self._reading_trailer: + lines = buf.maybe_extract_lines() + if lines is None: + return None + return EndOfMessage(headers=list(_decode_header_lines(lines))) + if self._bytes_to_discard > 0: + data = buf.maybe_extract_at_most(self._bytes_to_discard) + if data is None: + return None + self._bytes_to_discard -= len(data) + if self._bytes_to_discard > 0: + return None + # else, fall through and read some more + assert self._bytes_to_discard == 0 + if self._bytes_in_chunk == 0: + # We need to refill our chunk count + chunk_header = buf.maybe_extract_next_line() + if chunk_header is None: + return None + matches = validate( + chunk_header_re, + chunk_header, + "illegal chunk header: {!r}", + chunk_header, + ) + # XX FIXME: we discard chunk extensions. Does anyone care? + self._bytes_in_chunk = int(matches["chunk_size"], base=16) + if self._bytes_in_chunk == 0: + self._reading_trailer = True + return self(buf) + chunk_start = True + else: + chunk_start = False + assert self._bytes_in_chunk > 0 + data = buf.maybe_extract_at_most(self._bytes_in_chunk) + if data is None: + return None + self._bytes_in_chunk -= len(data) + if self._bytes_in_chunk == 0: + self._bytes_to_discard = 2 + chunk_end = True + else: + chunk_end = False + return Data(data=data, chunk_start=chunk_start, chunk_end=chunk_end) + + def read_eof(self) -> NoReturn: + raise RemoteProtocolError( + "peer closed connection without sending complete message body " + "(incomplete chunked read)" + ) + + +class Http10Reader: + def __call__(self, buf: ReceiveBuffer) -> Optional[Data]: + data = buf.maybe_extract_at_most(999999999) + if data is None: + return None + return Data(data=data) + + def read_eof(self) -> EndOfMessage: + return EndOfMessage() + + +def expect_nothing(buf: ReceiveBuffer) -> None: + if buf: + raise LocalProtocolError("Got data when expecting EOF") + return None + + +ReadersType = Dict[ + Union[Type[Sentinel], Tuple[Type[Sentinel], Type[Sentinel]]], + Union[Callable[..., Any], Dict[str, Callable[..., Any]]], +] + +READERS: ReadersType = { + (CLIENT, IDLE): maybe_read_from_IDLE_client, + (SERVER, IDLE): maybe_read_from_SEND_RESPONSE_server, + (SERVER, SEND_RESPONSE): maybe_read_from_SEND_RESPONSE_server, + (CLIENT, DONE): expect_nothing, + (CLIENT, MUST_CLOSE): expect_nothing, + (CLIENT, CLOSED): expect_nothing, + (SERVER, DONE): expect_nothing, + (SERVER, MUST_CLOSE): expect_nothing, + (SERVER, CLOSED): expect_nothing, + SEND_BODY: { + "chunked": ChunkedReader, + "content-length": ContentLengthReader, + "http/1.0": Http10Reader, + }, +} |