diff options
Diffstat (limited to 'venv/lib/python3.11/site-packages/h11/_headers.py')
| -rw-r--r-- | venv/lib/python3.11/site-packages/h11/_headers.py | 278 |
1 files changed, 0 insertions, 278 deletions
diff --git a/venv/lib/python3.11/site-packages/h11/_headers.py b/venv/lib/python3.11/site-packages/h11/_headers.py deleted file mode 100644 index b97d020..0000000 --- a/venv/lib/python3.11/site-packages/h11/_headers.py +++ /dev/null @@ -1,278 +0,0 @@ -import re -from typing import AnyStr, cast, List, overload, Sequence, Tuple, TYPE_CHECKING, Union - -from ._abnf import field_name, field_value -from ._util import bytesify, LocalProtocolError, validate - -if TYPE_CHECKING: - from ._events import Request - -try: - from typing import Literal -except ImportError: - from typing_extensions import Literal # type: ignore - - -# Facts -# ----- -# -# Headers are: -# keys: case-insensitive ascii -# values: mixture of ascii and raw bytes -# -# "Historically, HTTP has allowed field content with text in the ISO-8859-1 -# charset [ISO-8859-1], supporting other charsets only through use of -# [RFC2047] encoding. In practice, most HTTP header field values use only a -# subset of the US-ASCII charset [USASCII]. Newly defined header fields SHOULD -# limit their field values to US-ASCII octets. A recipient SHOULD treat other -# octets in field content (obs-text) as opaque data." -# And it deprecates all non-ascii values -# -# Leading/trailing whitespace in header names is forbidden -# -# Values get leading/trailing whitespace stripped -# -# Content-Disposition actually needs to contain unicode semantically; to -# accomplish this it has a terrifically weird way of encoding the filename -# itself as ascii (and even this still has lots of cross-browser -# incompatibilities) -# -# Order is important: -# "a proxy MUST NOT change the order of these field values when forwarding a -# message" -# (and there are several headers where the order indicates a preference) -# -# Multiple occurences of the same header: -# "A sender MUST NOT generate multiple header fields with the same field name -# in a message unless either the entire field value for that header field is -# defined as a comma-separated list [or the header is Set-Cookie which gets a -# special exception]" - RFC 7230. (cookies are in RFC 6265) -# -# So every header aside from Set-Cookie can be merged by b", ".join if it -# occurs repeatedly. But, of course, they can't necessarily be split by -# .split(b","), because quoting. -# -# Given all this mess (case insensitive, duplicates allowed, order is -# important, ...), there doesn't appear to be any standard way to handle -# headers in Python -- they're almost like dicts, but... actually just -# aren't. For now we punt and just use a super simple representation: headers -# are a list of pairs -# -# [(name1, value1), (name2, value2), ...] -# -# where all entries are bytestrings, names are lowercase and have no -# leading/trailing whitespace, and values are bytestrings with no -# leading/trailing whitespace. Searching and updating are done via naive O(n) -# methods. -# -# Maybe a dict-of-lists would be better? - -_content_length_re = re.compile(rb"[0-9]+") -_field_name_re = re.compile(field_name.encode("ascii")) -_field_value_re = re.compile(field_value.encode("ascii")) - - -class Headers(Sequence[Tuple[bytes, bytes]]): - """ - A list-like interface that allows iterating over headers as byte-pairs - of (lowercased-name, value). - - Internally we actually store the representation as three-tuples, - including both the raw original casing, in order to preserve casing - over-the-wire, and the lowercased name, for case-insensitive comparisions. - - r = Request( - method="GET", - target="/", - headers=[("Host", "example.org"), ("Connection", "keep-alive")], - http_version="1.1", - ) - assert r.headers == [ - (b"host", b"example.org"), - (b"connection", b"keep-alive") - ] - assert r.headers.raw_items() == [ - (b"Host", b"example.org"), - (b"Connection", b"keep-alive") - ] - """ - - __slots__ = "_full_items" - - def __init__(self, full_items: List[Tuple[bytes, bytes, bytes]]) -> None: - self._full_items = full_items - - def __bool__(self) -> bool: - return bool(self._full_items) - - def __eq__(self, other: object) -> bool: - return list(self) == list(other) # type: ignore - - def __len__(self) -> int: - return len(self._full_items) - - def __repr__(self) -> str: - return "<Headers(%s)>" % repr(list(self)) - - def __getitem__(self, idx: int) -> Tuple[bytes, bytes]: # type: ignore[override] - _, name, value = self._full_items[idx] - return (name, value) - - def raw_items(self) -> List[Tuple[bytes, bytes]]: - return [(raw_name, value) for raw_name, _, value in self._full_items] - - -HeaderTypes = Union[ - List[Tuple[bytes, bytes]], - List[Tuple[bytes, str]], - List[Tuple[str, bytes]], - List[Tuple[str, str]], -] - - -@overload -def normalize_and_validate(headers: Headers, _parsed: Literal[True]) -> Headers: - ... - - -@overload -def normalize_and_validate(headers: HeaderTypes, _parsed: Literal[False]) -> Headers: - ... - - -@overload -def normalize_and_validate( - headers: Union[Headers, HeaderTypes], _parsed: bool = False -) -> Headers: - ... - - -def normalize_and_validate( - headers: Union[Headers, HeaderTypes], _parsed: bool = False -) -> Headers: - new_headers = [] - seen_content_length = None - saw_transfer_encoding = False - for name, value in headers: - # For headers coming out of the parser, we can safely skip some steps, - # because it always returns bytes and has already run these regexes - # over the data: - if not _parsed: - name = bytesify(name) - value = bytesify(value) - validate(_field_name_re, name, "Illegal header name {!r}", name) - validate(_field_value_re, value, "Illegal header value {!r}", value) - assert isinstance(name, bytes) - assert isinstance(value, bytes) - - raw_name = name - name = name.lower() - if name == b"content-length": - lengths = {length.strip() for length in value.split(b",")} - if len(lengths) != 1: - raise LocalProtocolError("conflicting Content-Length headers") - value = lengths.pop() - validate(_content_length_re, value, "bad Content-Length") - if seen_content_length is None: - seen_content_length = value - new_headers.append((raw_name, name, value)) - elif seen_content_length != value: - raise LocalProtocolError("conflicting Content-Length headers") - elif name == b"transfer-encoding": - # "A server that receives a request message with a transfer coding - # it does not understand SHOULD respond with 501 (Not - # Implemented)." - # https://tools.ietf.org/html/rfc7230#section-3.3.1 - if saw_transfer_encoding: - raise LocalProtocolError( - "multiple Transfer-Encoding headers", error_status_hint=501 - ) - # "All transfer-coding names are case-insensitive" - # -- https://tools.ietf.org/html/rfc7230#section-4 - value = value.lower() - if value != b"chunked": - raise LocalProtocolError( - "Only Transfer-Encoding: chunked is supported", - error_status_hint=501, - ) - saw_transfer_encoding = True - new_headers.append((raw_name, name, value)) - else: - new_headers.append((raw_name, name, value)) - return Headers(new_headers) - - -def get_comma_header(headers: Headers, name: bytes) -> List[bytes]: - # Should only be used for headers whose value is a list of - # comma-separated, case-insensitive values. - # - # The header name `name` is expected to be lower-case bytes. - # - # Connection: meets these criteria (including cast insensitivity). - # - # Content-Length: technically is just a single value (1*DIGIT), but the - # standard makes reference to implementations that do multiple values, and - # using this doesn't hurt. Ditto, case insensitivity doesn't things either - # way. - # - # Transfer-Encoding: is more complex (allows for quoted strings), so - # splitting on , is actually wrong. For example, this is legal: - # - # Transfer-Encoding: foo; options="1,2", chunked - # - # and should be parsed as - # - # foo; options="1,2" - # chunked - # - # but this naive function will parse it as - # - # foo; options="1 - # 2" - # chunked - # - # However, this is okay because the only thing we are going to do with - # any Transfer-Encoding is reject ones that aren't just "chunked", so - # both of these will be treated the same anyway. - # - # Expect: the only legal value is the literal string - # "100-continue". Splitting on commas is harmless. Case insensitive. - # - out: List[bytes] = [] - for _, found_name, found_raw_value in headers._full_items: - if found_name == name: - found_raw_value = found_raw_value.lower() - for found_split_value in found_raw_value.split(b","): - found_split_value = found_split_value.strip() - if found_split_value: - out.append(found_split_value) - return out - - -def set_comma_header(headers: Headers, name: bytes, new_values: List[bytes]) -> Headers: - # The header name `name` is expected to be lower-case bytes. - # - # Note that when we store the header we use title casing for the header - # names, in order to match the conventional HTTP header style. - # - # Simply calling `.title()` is a blunt approach, but it's correct - # here given the cases where we're using `set_comma_header`... - # - # Connection, Content-Length, Transfer-Encoding. - new_headers: List[Tuple[bytes, bytes]] = [] - for found_raw_name, found_name, found_raw_value in headers._full_items: - if found_name != name: - new_headers.append((found_raw_name, found_raw_value)) - for new_value in new_values: - new_headers.append((name.title(), new_value)) - return normalize_and_validate(new_headers) - - -def has_expect_100_continue(request: "Request") -> bool: - # https://tools.ietf.org/html/rfc7231#section-5.1.1 - # "A server that receives a 100-continue expectation in an HTTP/1.0 request - # MUST ignore that expectation." - if request.http_version < b"1.1": - return False - expect = get_comma_header(request.headers, b"expect") - return b"100-continue" in expect |