two version of R2R are here HEAD master

1 files changed, 1071 insertions, 0 deletions

diff --git a/.venv/lib/python3.12/site-packages/aiohttp/multipart.py b/.venv/lib/python3.12/site-packages/aiohttp/multipart.py
new file mode 100644
index 00000000..bd4d8ae1
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/aiohttp/multipart.py
@@ -0,0 +1,1071 @@
+import base64
+import binascii
+import json
+import re
+import sys
+import uuid
+import warnings
+import zlib
+from collections import deque
+from types import TracebackType
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Deque,
+    Dict,
+    Iterator,
+    List,
+    Mapping,
+    Optional,
+    Sequence,
+    Tuple,
+    Type,
+    Union,
+    cast,
+)
+from urllib.parse import parse_qsl, unquote, urlencode
+
+from multidict import CIMultiDict, CIMultiDictProxy
+
+from .compression_utils import ZLibCompressor, ZLibDecompressor
+from .hdrs import (
+    CONTENT_DISPOSITION,
+    CONTENT_ENCODING,
+    CONTENT_LENGTH,
+    CONTENT_TRANSFER_ENCODING,
+    CONTENT_TYPE,
+)
+from .helpers import CHAR, TOKEN, parse_mimetype, reify
+from .http import HeadersParser
+from .payload import (
+    JsonPayload,
+    LookupError,
+    Order,
+    Payload,
+    StringPayload,
+    get_payload,
+    payload_type,
+)
+from .streams import StreamReader
+
+if sys.version_info >= (3, 11):
+    from typing import Self
+else:
+    from typing import TypeVar
+
+    Self = TypeVar("Self", bound="BodyPartReader")
+
+__all__ = (
+    "MultipartReader",
+    "MultipartWriter",
+    "BodyPartReader",
+    "BadContentDispositionHeader",
+    "BadContentDispositionParam",
+    "parse_content_disposition",
+    "content_disposition_filename",
+)
+
+
+if TYPE_CHECKING:
+    from .client_reqrep import ClientResponse
+
+
+class BadContentDispositionHeader(RuntimeWarning):
+    pass
+
+
+class BadContentDispositionParam(RuntimeWarning):
+    pass
+
+
+def parse_content_disposition(
+    header: Optional[str],
+) -> Tuple[Optional[str], Dict[str, str]]:
+    def is_token(string: str) -> bool:
+        return bool(string) and TOKEN >= set(string)
+
+    def is_quoted(string: str) -> bool:
+        return string[0] == string[-1] == '"'
+
+    def is_rfc5987(string: str) -> bool:
+        return is_token(string) and string.count("'") == 2
+
+    def is_extended_param(string: str) -> bool:
+        return string.endswith("*")
+
+    def is_continuous_param(string: str) -> bool:
+        pos = string.find("*") + 1
+        if not pos:
+            return False
+        substring = string[pos:-1] if string.endswith("*") else string[pos:]
+        return substring.isdigit()
+
+    def unescape(text: str, *, chars: str = "".join(map(re.escape, CHAR))) -> str:
+        return re.sub(f"\\\\([{chars}])", "\\1", text)
+
+    if not header:
+        return None, {}
+
+    disptype, *parts = header.split(";")
+    if not is_token(disptype):
+        warnings.warn(BadContentDispositionHeader(header))
+        return None, {}
+
+    params: Dict[str, str] = {}
+    while parts:
+        item = parts.pop(0)
+
+        if "=" not in item:
+            warnings.warn(BadContentDispositionHeader(header))
+            return None, {}
+
+        key, value = item.split("=", 1)
+        key = key.lower().strip()
+        value = value.lstrip()
+
+        if key in params:
+            warnings.warn(BadContentDispositionHeader(header))
+            return None, {}
+
+        if not is_token(key):
+            warnings.warn(BadContentDispositionParam(item))
+            continue
+
+        elif is_continuous_param(key):
+            if is_quoted(value):
+                value = unescape(value[1:-1])
+            elif not is_token(value):
+                warnings.warn(BadContentDispositionParam(item))
+                continue
+
+        elif is_extended_param(key):
+            if is_rfc5987(value):
+                encoding, _, value = value.split("'", 2)
+                encoding = encoding or "utf-8"
+            else:
+                warnings.warn(BadContentDispositionParam(item))
+                continue
+
+            try:
+                value = unquote(value, encoding, "strict")
+            except UnicodeDecodeError:  # pragma: nocover
+                warnings.warn(BadContentDispositionParam(item))
+                continue
+
+        else:
+            failed = True
+            if is_quoted(value):
+                failed = False
+                value = unescape(value[1:-1].lstrip("\\/"))
+            elif is_token(value):
+                failed = False
+            elif parts:
+                # maybe just ; in filename, in any case this is just
+                # one case fix, for proper fix we need to redesign parser
+                _value = f"{value};{parts[0]}"
+                if is_quoted(_value):
+                    parts.pop(0)
+                    value = unescape(_value[1:-1].lstrip("\\/"))
+                    failed = False
+
+            if failed:
+                warnings.warn(BadContentDispositionHeader(header))
+                return None, {}
+
+        params[key] = value
+
+    return disptype.lower(), params
+
+
+def content_disposition_filename(
+    params: Mapping[str, str], name: str = "filename"
+) -> Optional[str]:
+    name_suf = "%s*" % name
+    if not params:
+        return None
+    elif name_suf in params:
+        return params[name_suf]
+    elif name in params:
+        return params[name]
+    else:
+        parts = []
+        fnparams = sorted(
+            (key, value) for key, value in params.items() if key.startswith(name_suf)
+        )
+        for num, (key, value) in enumerate(fnparams):
+            _, tail = key.split("*", 1)
+            if tail.endswith("*"):
+                tail = tail[:-1]
+            if tail == str(num):
+                parts.append(value)
+            else:
+                break
+        if not parts:
+            return None
+        value = "".join(parts)
+        if "'" in value:
+            encoding, _, value = value.split("'", 2)
+            encoding = encoding or "utf-8"
+            return unquote(value, encoding, "strict")
+        return value
+
+
+class MultipartResponseWrapper:
+    """Wrapper around the MultipartReader.
+
+    It takes care about
+    underlying connection and close it when it needs in.
+    """
+
+    def __init__(
+        self,
+        resp: "ClientResponse",
+        stream: "MultipartReader",
+    ) -> None:
+        self.resp = resp
+        self.stream = stream
+
+    def __aiter__(self) -> "MultipartResponseWrapper":
+        return self
+
+    async def __anext__(
+        self,
+    ) -> Union["MultipartReader", "BodyPartReader"]:
+        part = await self.next()
+        if part is None:
+            raise StopAsyncIteration
+        return part
+
+    def at_eof(self) -> bool:
+        """Returns True when all response data had been read."""
+        return self.resp.content.at_eof()
+
+    async def next(
+        self,
+    ) -> Optional[Union["MultipartReader", "BodyPartReader"]]:
+        """Emits next multipart reader object."""
+        item = await self.stream.next()
+        if self.stream.at_eof():
+            await self.release()
+        return item
+
+    async def release(self) -> None:
+        """Release the connection gracefully.
+
+        All remaining content is read to the void.
+        """
+        await self.resp.release()
+
+
+class BodyPartReader:
+    """Multipart reader for single body part."""
+
+    chunk_size = 8192
+
+    def __init__(
+        self,
+        boundary: bytes,
+        headers: "CIMultiDictProxy[str]",
+        content: StreamReader,
+        *,
+        subtype: str = "mixed",
+        default_charset: Optional[str] = None,
+    ) -> None:
+        self.headers = headers
+        self._boundary = boundary
+        self._boundary_len = len(boundary) + 2  # Boundary + \r\n
+        self._content = content
+        self._default_charset = default_charset
+        self._at_eof = False
+        self._is_form_data = subtype == "form-data"
+        # https://datatracker.ietf.org/doc/html/rfc7578#section-4.8
+        length = None if self._is_form_data else self.headers.get(CONTENT_LENGTH, None)
+        self._length = int(length) if length is not None else None
+        self._read_bytes = 0
+        self._unread: Deque[bytes] = deque()
+        self._prev_chunk: Optional[bytes] = None
+        self._content_eof = 0
+        self._cache: Dict[str, Any] = {}
+
+    def __aiter__(self: Self) -> Self:
+        return self
+
+    async def __anext__(self) -> bytes:
+        part = await self.next()
+        if part is None:
+            raise StopAsyncIteration
+        return part
+
+    async def next(self) -> Optional[bytes]:
+        item = await self.read()
+        if not item:
+            return None
+        return item
+
+    async def read(self, *, decode: bool = False) -> bytes:
+        """Reads body part data.
+
+        decode: Decodes data following by encoding
+                method from Content-Encoding header. If it missed
+                data remains untouched
+        """
+        if self._at_eof:
+            return b""
+        data = bytearray()
+        while not self._at_eof:
+            data.extend(await self.read_chunk(self.chunk_size))
+        if decode:
+            return self.decode(data)
+        return data
+
+    async def read_chunk(self, size: int = chunk_size) -> bytes:
+        """Reads body part content chunk of the specified size.
+
+        size: chunk size
+        """
+        if self._at_eof:
+            return b""
+        if self._length:
+            chunk = await self._read_chunk_from_length(size)
+        else:
+            chunk = await self._read_chunk_from_stream(size)
+
+        # For the case of base64 data, we must read a fragment of size with a
+        # remainder of 0 by dividing by 4 for string without symbols \n or \r
+        encoding = self.headers.get(CONTENT_TRANSFER_ENCODING)
+        if encoding and encoding.lower() == "base64":
+            stripped_chunk = b"".join(chunk.split())
+            remainder = len(stripped_chunk) % 4
+
+            while remainder != 0 and not self.at_eof():
+                over_chunk_size = 4 - remainder
+                over_chunk = b""
+
+                if self._prev_chunk:
+                    over_chunk = self._prev_chunk[:over_chunk_size]
+                    self._prev_chunk = self._prev_chunk[len(over_chunk) :]
+
+                if len(over_chunk) != over_chunk_size:
+                    over_chunk += await self._content.read(4 - len(over_chunk))
+
+                if not over_chunk:
+                    self._at_eof = True
+
+                stripped_chunk += b"".join(over_chunk.split())
+                chunk += over_chunk
+                remainder = len(stripped_chunk) % 4
+
+        self._read_bytes += len(chunk)
+        if self._read_bytes == self._length:
+            self._at_eof = True
+        if self._at_eof:
+            clrf = await self._content.readline()
+            assert (
+                b"\r\n" == clrf
+            ), "reader did not read all the data or it is malformed"
+        return chunk
+
+    async def _read_chunk_from_length(self, size: int) -> bytes:
+        # Reads body part content chunk of the specified size.
+        # The body part must has Content-Length header with proper value.
+        assert self._length is not None, "Content-Length required for chunked read"
+        chunk_size = min(size, self._length - self._read_bytes)
+        chunk = await self._content.read(chunk_size)
+        if self._content.at_eof():
+            self._at_eof = True
+        return chunk
+
+    async def _read_chunk_from_stream(self, size: int) -> bytes:
+        # Reads content chunk of body part with unknown length.
+        # The Content-Length header for body part is not necessary.
+        assert (
+            size >= self._boundary_len
+        ), "Chunk size must be greater or equal than boundary length + 2"
+        first_chunk = self._prev_chunk is None
+        if first_chunk:
+            self._prev_chunk = await self._content.read(size)
+
+        chunk = b""
+        # content.read() may return less than size, so we need to loop to ensure
+        # we have enough data to detect the boundary.
+        while len(chunk) < self._boundary_len:
+            chunk += await self._content.read(size)
+            self._content_eof += int(self._content.at_eof())
+            assert self._content_eof < 3, "Reading after EOF"
+            if self._content_eof:
+                break
+        if len(chunk) > size:
+            self._content.unread_data(chunk[size:])
+            chunk = chunk[:size]
+
+        assert self._prev_chunk is not None
+        window = self._prev_chunk + chunk
+        sub = b"\r\n" + self._boundary
+        if first_chunk:
+            idx = window.find(sub)
+        else:
+            idx = window.find(sub, max(0, len(self._prev_chunk) - len(sub)))
+        if idx >= 0:
+            # pushing boundary back to content
+            with warnings.catch_warnings():
+                warnings.filterwarnings("ignore", category=DeprecationWarning)
+                self._content.unread_data(window[idx:])
+            if size > idx:
+                self._prev_chunk = self._prev_chunk[:idx]
+            chunk = window[len(self._prev_chunk) : idx]
+            if not chunk:
+                self._at_eof = True
+        result = self._prev_chunk
+        self._prev_chunk = chunk
+        return result
+
+    async def readline(self) -> bytes:
+        """Reads body part by line by line."""
+        if self._at_eof:
+            return b""
+
+        if self._unread:
+            line = self._unread.popleft()
+        else:
+            line = await self._content.readline()
+
+        if line.startswith(self._boundary):
+            # the very last boundary may not come with \r\n,
+            # so set single rules for everyone
+            sline = line.rstrip(b"\r\n")
+            boundary = self._boundary
+            last_boundary = self._boundary + b"--"
+            # ensure that we read exactly the boundary, not something alike
+            if sline == boundary or sline == last_boundary:
+                self._at_eof = True
+                self._unread.append(line)
+                return b""
+        else:
+            next_line = await self._content.readline()
+            if next_line.startswith(self._boundary):
+                line = line[:-2]  # strip CRLF but only once
+            self._unread.append(next_line)
+
+        return line
+
+    async def release(self) -> None:
+        """Like read(), but reads all the data to the void."""
+        if self._at_eof:
+            return
+        while not self._at_eof:
+            await self.read_chunk(self.chunk_size)
+
+    async def text(self, *, encoding: Optional[str] = None) -> str:
+        """Like read(), but assumes that body part contains text data."""
+        data = await self.read(decode=True)
+        # see https://www.w3.org/TR/html5/forms.html#multipart/form-data-encoding-algorithm
+        # and https://dvcs.w3.org/hg/xhr/raw-file/tip/Overview.html#dom-xmlhttprequest-send
+        encoding = encoding or self.get_charset(default="utf-8")
+        return data.decode(encoding)
+
+    async def json(self, *, encoding: Optional[str] = None) -> Optional[Dict[str, Any]]:
+        """Like read(), but assumes that body parts contains JSON data."""
+        data = await self.read(decode=True)
+        if not data:
+            return None
+        encoding = encoding or self.get_charset(default="utf-8")
+        return cast(Dict[str, Any], json.loads(data.decode(encoding)))
+
+    async def form(self, *, encoding: Optional[str] = None) -> List[Tuple[str, str]]:
+        """Like read(), but assumes that body parts contain form urlencoded data."""
+        data = await self.read(decode=True)
+        if not data:
+            return []
+        if encoding is not None:
+            real_encoding = encoding
+        else:
+            real_encoding = self.get_charset(default="utf-8")
+        try:
+            decoded_data = data.rstrip().decode(real_encoding)
+        except UnicodeDecodeError:
+            raise ValueError("data cannot be decoded with %s encoding" % real_encoding)
+
+        return parse_qsl(
+            decoded_data,
+            keep_blank_values=True,
+            encoding=real_encoding,
+        )
+
+    def at_eof(self) -> bool:
+        """Returns True if the boundary was reached or False otherwise."""
+        return self._at_eof
+
+    def decode(self, data: bytes) -> bytes:
+        """Decodes data.
+
+        Decoding is done according the specified Content-Encoding
+        or Content-Transfer-Encoding headers value.
+        """
+        if CONTENT_TRANSFER_ENCODING in self.headers:
+            data = self._decode_content_transfer(data)
+        # https://datatracker.ietf.org/doc/html/rfc7578#section-4.8
+        if not self._is_form_data and CONTENT_ENCODING in self.headers:
+            return self._decode_content(data)
+        return data
+
+    def _decode_content(self, data: bytes) -> bytes:
+        encoding = self.headers.get(CONTENT_ENCODING, "").lower()
+        if encoding == "identity":
+            return data
+        if encoding in {"deflate", "gzip"}:
+            return ZLibDecompressor(
+                encoding=encoding,
+                suppress_deflate_header=True,
+            ).decompress_sync(data)
+
+        raise RuntimeError(f"unknown content encoding: {encoding}")
+
+    def _decode_content_transfer(self, data: bytes) -> bytes:
+        encoding = self.headers.get(CONTENT_TRANSFER_ENCODING, "").lower()
+
+        if encoding == "base64":
+            return base64.b64decode(data)
+        elif encoding == "quoted-printable":
+            return binascii.a2b_qp(data)
+        elif encoding in ("binary", "8bit", "7bit"):
+            return data
+        else:
+            raise RuntimeError(f"unknown content transfer encoding: {encoding}")
+
+    def get_charset(self, default: str) -> str:
+        """Returns charset parameter from Content-Type header or default."""
+        ctype = self.headers.get(CONTENT_TYPE, "")
+        mimetype = parse_mimetype(ctype)
+        return mimetype.parameters.get("charset", self._default_charset or default)
+
+    @reify
+    def name(self) -> Optional[str]:
+        """Returns name specified in Content-Disposition header.
+
+        If the header is missing or malformed, returns None.
+        """
+        _, params = parse_content_disposition(self.headers.get(CONTENT_DISPOSITION))
+        return content_disposition_filename(params, "name")
+
+    @reify
+    def filename(self) -> Optional[str]:
+        """Returns filename specified in Content-Disposition header.
+
+        Returns None if the header is missing or malformed.
+        """
+        _, params = parse_content_disposition(self.headers.get(CONTENT_DISPOSITION))
+        return content_disposition_filename(params, "filename")
+
+
+@payload_type(BodyPartReader, order=Order.try_first)
+class BodyPartReaderPayload(Payload):
+    _value: BodyPartReader
+
+    def __init__(self, value: BodyPartReader, *args: Any, **kwargs: Any) -> None:
+        super().__init__(value, *args, **kwargs)
+
+        params: Dict[str, str] = {}
+        if value.name is not None:
+            params["name"] = value.name
+        if value.filename is not None:
+            params["filename"] = value.filename
+
+        if params:
+            self.set_content_disposition("attachment", True, **params)
+
+    def decode(self, encoding: str = "utf-8", errors: str = "strict") -> str:
+        raise TypeError("Unable to decode.")
+
+    async def write(self, writer: Any) -> None:
+        field = self._value
+        chunk = await field.read_chunk(size=2**16)
+        while chunk:
+            await writer.write(field.decode(chunk))
+            chunk = await field.read_chunk(size=2**16)
+
+
+class MultipartReader:
+    """Multipart body reader."""
+
+    #: Response wrapper, used when multipart readers constructs from response.
+    response_wrapper_cls = MultipartResponseWrapper
+    #: Multipart reader class, used to handle multipart/* body parts.
+    #: None points to type(self)
+    multipart_reader_cls: Optional[Type["MultipartReader"]] = None
+    #: Body part reader class for non multipart/* content types.
+    part_reader_cls = BodyPartReader
+
+    def __init__(self, headers: Mapping[str, str], content: StreamReader) -> None:
+        self._mimetype = parse_mimetype(headers[CONTENT_TYPE])
+        assert self._mimetype.type == "multipart", "multipart/* content type expected"
+        if "boundary" not in self._mimetype.parameters:
+            raise ValueError(
+                "boundary missed for Content-Type: %s" % headers[CONTENT_TYPE]
+            )
+
+        self.headers = headers
+        self._boundary = ("--" + self._get_boundary()).encode()
+        self._content = content
+        self._default_charset: Optional[str] = None
+        self._last_part: Optional[Union["MultipartReader", BodyPartReader]] = None
+        self._at_eof = False
+        self._at_bof = True
+        self._unread: List[bytes] = []
+
+    def __aiter__(self: Self) -> Self:
+        return self
+
+    async def __anext__(
+        self,
+    ) -> Optional[Union["MultipartReader", BodyPartReader]]:
+        part = await self.next()
+        if part is None:
+            raise StopAsyncIteration
+        return part
+
+    @classmethod
+    def from_response(
+        cls,
+        response: "ClientResponse",
+    ) -> MultipartResponseWrapper:
+        """Constructs reader instance from HTTP response.
+
+        :param response: :class:`~aiohttp.client.ClientResponse` instance
+        """
+        obj = cls.response_wrapper_cls(
+            response, cls(response.headers, response.content)
+        )
+        return obj
+
+    def at_eof(self) -> bool:
+        """Returns True if the final boundary was reached, false otherwise."""
+        return self._at_eof
+
+    async def next(
+        self,
+    ) -> Optional[Union["MultipartReader", BodyPartReader]]:
+        """Emits the next multipart body part."""
+        # So, if we're at BOF, we need to skip till the boundary.
+        if self._at_eof:
+            return None
+        await self._maybe_release_last_part()
+        if self._at_bof:
+            await self._read_until_first_boundary()
+            self._at_bof = False
+        else:
+            await self._read_boundary()
+        if self._at_eof:  # we just read the last boundary, nothing to do there
+            return None
+
+        part = await self.fetch_next_part()
+        # https://datatracker.ietf.org/doc/html/rfc7578#section-4.6
+        if (
+            self._last_part is None
+            and self._mimetype.subtype == "form-data"
+            and isinstance(part, BodyPartReader)
+        ):
+            _, params = parse_content_disposition(part.headers.get(CONTENT_DISPOSITION))
+            if params.get("name") == "_charset_":
+                # Longest encoding in https://encoding.spec.whatwg.org/encodings.json
+                # is 19 characters, so 32 should be more than enough for any valid encoding.
+                charset = await part.read_chunk(32)
+                if len(charset) > 31:
+                    raise RuntimeError("Invalid default charset")
+                self._default_charset = charset.strip().decode()
+                part = await self.fetch_next_part()
+        self._last_part = part
+        return self._last_part
+
+    async def release(self) -> None:
+        """Reads all the body parts to the void till the final boundary."""
+        while not self._at_eof:
+            item = await self.next()
+            if item is None:
+                break
+            await item.release()
+
+    async def fetch_next_part(
+        self,
+    ) -> Union["MultipartReader", BodyPartReader]:
+        """Returns the next body part reader."""
+        headers = await self._read_headers()
+        return self._get_part_reader(headers)
+
+    def _get_part_reader(
+        self,
+        headers: "CIMultiDictProxy[str]",
+    ) -> Union["MultipartReader", BodyPartReader]:
+        """Dispatches the response by the `Content-Type` header.
+
+        Returns a suitable reader instance.
+
+        :param dict headers: Response headers
+        """
+        ctype = headers.get(CONTENT_TYPE, "")
+        mimetype = parse_mimetype(ctype)
+
+        if mimetype.type == "multipart":
+            if self.multipart_reader_cls is None:
+                return type(self)(headers, self._content)
+            return self.multipart_reader_cls(headers, self._content)
+        else:
+            return self.part_reader_cls(
+                self._boundary,
+                headers,
+                self._content,
+                subtype=self._mimetype.subtype,
+                default_charset=self._default_charset,
+            )
+
+    def _get_boundary(self) -> str:
+        boundary = self._mimetype.parameters["boundary"]
+        if len(boundary) > 70:
+            raise ValueError("boundary %r is too long (70 chars max)" % boundary)
+
+        return boundary
+
+    async def _readline(self) -> bytes:
+        if self._unread:
+            return self._unread.pop()
+        return await self._content.readline()
+
+    async def _read_until_first_boundary(self) -> None:
+        while True:
+            chunk = await self._readline()
+            if chunk == b"":
+                raise ValueError(
+                    "Could not find starting boundary %r" % (self._boundary)
+                )
+            chunk = chunk.rstrip()
+            if chunk == self._boundary:
+                return
+            elif chunk == self._boundary + b"--":
+                self._at_eof = True
+                return
+
+    async def _read_boundary(self) -> None:
+        chunk = (await self._readline()).rstrip()
+        if chunk == self._boundary:
+            pass
+        elif chunk == self._boundary + b"--":
+            self._at_eof = True
+            epilogue = await self._readline()
+            next_line = await self._readline()
+
+            # the epilogue is expected and then either the end of input or the
+            # parent multipart boundary, if the parent boundary is found then
+            # it should be marked as unread and handed to the parent for
+            # processing
+            if next_line[:2] == b"--":
+                self._unread.append(next_line)
+            # otherwise the request is likely missing an epilogue and both
+            # lines should be passed to the parent for processing
+            # (this handles the old behavior gracefully)
+            else:
+                self._unread.extend([next_line, epilogue])
+        else:
+            raise ValueError(f"Invalid boundary {chunk!r}, expected {self._boundary!r}")
+
+    async def _read_headers(self) -> "CIMultiDictProxy[str]":
+        lines = [b""]
+        while True:
+            chunk = await self._content.readline()
+            chunk = chunk.strip()
+            lines.append(chunk)
+            if not chunk:
+                break
+        parser = HeadersParser()
+        headers, raw_headers = parser.parse_headers(lines)
+        return headers
+
+    async def _maybe_release_last_part(self) -> None:
+        """Ensures that the last read body part is read completely."""
+        if self._last_part is not None:
+            if not self._last_part.at_eof():
+                await self._last_part.release()
+            self._unread.extend(self._last_part._unread)
+            self._last_part = None
+
+
+_Part = Tuple[Payload, str, str]
+
+
+class MultipartWriter(Payload):
+    """Multipart body writer."""
+
+    _value: None
+
+    def __init__(self, subtype: str = "mixed", boundary: Optional[str] = None) -> None:
+        boundary = boundary if boundary is not None else uuid.uuid4().hex
+        # The underlying Payload API demands a str (utf-8), not bytes,
+        # so we need to ensure we don't lose anything during conversion.
+        # As a result, require the boundary to be ASCII only.
+        # In both situations.
+
+        try:
+            self._boundary = boundary.encode("ascii")
+        except UnicodeEncodeError:
+            raise ValueError("boundary should contain ASCII only chars") from None
+        ctype = f"multipart/{subtype}; boundary={self._boundary_value}"
+
+        super().__init__(None, content_type=ctype)
+
+        self._parts: List[_Part] = []
+        self._is_form_data = subtype == "form-data"
+
+    def __enter__(self) -> "MultipartWriter":
+        return self
+
+    def __exit__(
+        self,
+        exc_type: Optional[Type[BaseException]],
+        exc_val: Optional[BaseException],
+        exc_tb: Optional[TracebackType],
+    ) -> None:
+        pass
+
+    def __iter__(self) -> Iterator[_Part]:
+        return iter(self._parts)
+
+    def __len__(self) -> int:
+        return len(self._parts)
+
+    def __bool__(self) -> bool:
+        return True
+
+    _valid_tchar_regex = re.compile(rb"\A[!#$%&'*+\-.^_`|~\w]+\Z")
+    _invalid_qdtext_char_regex = re.compile(rb"[\x00-\x08\x0A-\x1F\x7F]")
+
+    @property
+    def _boundary_value(self) -> str:
+        """Wrap boundary parameter value in quotes, if necessary.
+
+        Reads self.boundary and returns a unicode string.
+        """
+        # Refer to RFCs 7231, 7230, 5234.
+        #
+        # parameter      = token "=" ( token / quoted-string )
+        # token          = 1*tchar
+        # quoted-string  = DQUOTE *( qdtext / quoted-pair ) DQUOTE
+        # qdtext         = HTAB / SP / %x21 / %x23-5B / %x5D-7E / obs-text
+        # obs-text       = %x80-FF
+        # quoted-pair    = "\" ( HTAB / SP / VCHAR / obs-text )
+        # tchar          = "!" / "#" / "$" / "%" / "&" / "'" / "*"
+        #                  / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
+        #                  / DIGIT / ALPHA
+        #                  ; any VCHAR, except delimiters
+        # VCHAR           = %x21-7E
+        value = self._boundary
+        if re.match(self._valid_tchar_regex, value):
+            return value.decode("ascii")  # cannot fail
+
+        if re.search(self._invalid_qdtext_char_regex, value):
+            raise ValueError("boundary value contains invalid characters")
+
+        # escape %x5C and %x22
+        quoted_value_content = value.replace(b"\\", b"\\\\")
+        quoted_value_content = quoted_value_content.replace(b'"', b'\\"')
+
+        return '"' + quoted_value_content.decode("ascii") + '"'
+
+    @property
+    def boundary(self) -> str:
+        return self._boundary.decode("ascii")
+
+    def append(self, obj: Any, headers: Optional[Mapping[str, str]] = None) -> Payload:
+        if headers is None:
+            headers = CIMultiDict()
+
+        if isinstance(obj, Payload):
+            obj.headers.update(headers)
+            return self.append_payload(obj)
+        else:
+            try:
+                payload = get_payload(obj, headers=headers)
+            except LookupError:
+                raise TypeError("Cannot create payload from %r" % obj)
+            else:
+                return self.append_payload(payload)
+
+    def append_payload(self, payload: Payload) -> Payload:
+        """Adds a new body part to multipart writer."""
+        encoding: Optional[str] = None
+        te_encoding: Optional[str] = None
+        if self._is_form_data:
+            # https://datatracker.ietf.org/doc/html/rfc7578#section-4.7
+            # https://datatracker.ietf.org/doc/html/rfc7578#section-4.8
+            assert (
+                not {CONTENT_ENCODING, CONTENT_LENGTH, CONTENT_TRANSFER_ENCODING}
+                & payload.headers.keys()
+            )
+            # Set default Content-Disposition in case user doesn't create one
+            if CONTENT_DISPOSITION not in payload.headers:
+                name = f"section-{len(self._parts)}"
+                payload.set_content_disposition("form-data", name=name)
+        else:
+            # compression
+            encoding = payload.headers.get(CONTENT_ENCODING, "").lower()
+            if encoding and encoding not in ("deflate", "gzip", "identity"):
+                raise RuntimeError(f"unknown content encoding: {encoding}")
+            if encoding == "identity":
+                encoding = None
+
+            # te encoding
+            te_encoding = payload.headers.get(CONTENT_TRANSFER_ENCODING, "").lower()
+            if te_encoding not in ("", "base64", "quoted-printable", "binary"):
+                raise RuntimeError(f"unknown content transfer encoding: {te_encoding}")
+            if te_encoding == "binary":
+                te_encoding = None
+
+            # size
+            size = payload.size
+            if size is not None and not (encoding or te_encoding):
+                payload.headers[CONTENT_LENGTH] = str(size)
+
+        self._parts.append((payload, encoding, te_encoding))  # type: ignore[arg-type]
+        return payload
+
+    def append_json(
+        self, obj: Any, headers: Optional[Mapping[str, str]] = None
+    ) -> Payload:
+        """Helper to append JSON part."""
+        if headers is None:
+            headers = CIMultiDict()
+
+        return self.append_payload(JsonPayload(obj, headers=headers))
+
+    def append_form(
+        self,
+        obj: Union[Sequence[Tuple[str, str]], Mapping[str, str]],
+        headers: Optional[Mapping[str, str]] = None,
+    ) -> Payload:
+        """Helper to append form urlencoded part."""
+        assert isinstance(obj, (Sequence, Mapping))
+
+        if headers is None:
+            headers = CIMultiDict()
+
+        if isinstance(obj, Mapping):
+            obj = list(obj.items())
+        data = urlencode(obj, doseq=True)
+
+        return self.append_payload(
+            StringPayload(
+                data, headers=headers, content_type="application/x-www-form-urlencoded"
+            )
+        )
+
+    @property
+    def size(self) -> Optional[int]:
+        """Size of the payload."""
+        total = 0
+        for part, encoding, te_encoding in self._parts:
+            if encoding or te_encoding or part.size is None:
+                return None
+
+            total += int(
+                2
+                + len(self._boundary)
+                + 2
+                + part.size  # b'--'+self._boundary+b'\r\n'
+                + len(part._binary_headers)
+                + 2  # b'\r\n'
+            )
+
+        total += 2 + len(self._boundary) + 4  # b'--'+self._boundary+b'--\r\n'
+        return total
+
+    def decode(self, encoding: str = "utf-8", errors: str = "strict") -> str:
+        return "".join(
+            "--"
+            + self.boundary
+            + "\r\n"
+            + part._binary_headers.decode(encoding, errors)
+            + part.decode()
+            for part, _e, _te in self._parts
+        )
+
+    async def write(self, writer: Any, close_boundary: bool = True) -> None:
+        """Write body."""
+        for part, encoding, te_encoding in self._parts:
+            if self._is_form_data:
+                # https://datatracker.ietf.org/doc/html/rfc7578#section-4.2
+                assert CONTENT_DISPOSITION in part.headers
+                assert "name=" in part.headers[CONTENT_DISPOSITION]
+
+            await writer.write(b"--" + self._boundary + b"\r\n")
+            await writer.write(part._binary_headers)
+
+            if encoding or te_encoding:
+                w = MultipartPayloadWriter(writer)
+                if encoding:
+                    w.enable_compression(encoding)
+                if te_encoding:
+                    w.enable_encoding(te_encoding)
+                await part.write(w)  # type: ignore[arg-type]
+                await w.write_eof()
+            else:
+                await part.write(writer)
+
+            await writer.write(b"\r\n")
+
+        if close_boundary:
+            await writer.write(b"--" + self._boundary + b"--\r\n")
+
+
+class MultipartPayloadWriter:
+    def __init__(self, writer: Any) -> None:
+        self._writer = writer
+        self._encoding: Optional[str] = None
+        self._compress: Optional[ZLibCompressor] = None
+        self._encoding_buffer: Optional[bytearray] = None
+
+    def enable_encoding(self, encoding: str) -> None:
+        if encoding == "base64":
+            self._encoding = encoding
+            self._encoding_buffer = bytearray()
+        elif encoding == "quoted-printable":
+            self._encoding = "quoted-printable"
+
+    def enable_compression(
+        self, encoding: str = "deflate", strategy: int = zlib.Z_DEFAULT_STRATEGY
+    ) -> None:
+        self._compress = ZLibCompressor(
+            encoding=encoding,
+            suppress_deflate_header=True,
+            strategy=strategy,
+        )
+
+    async def write_eof(self) -> None:
+        if self._compress is not None:
+            chunk = self._compress.flush()
+            if chunk:
+                self._compress = None
+                await self.write(chunk)
+
+        if self._encoding == "base64":
+            if self._encoding_buffer:
+                await self._writer.write(base64.b64encode(self._encoding_buffer))
+
+    async def write(self, chunk: bytes) -> None:
+        if self._compress is not None:
+            if chunk:
+                chunk = await self._compress.compress(chunk)
+                if not chunk:
+                    return
+
+        if self._encoding == "base64":
+            buf = self._encoding_buffer
+            assert buf is not None
+            buf.extend(chunk)
+
+            if buf:
+                div, mod = divmod(len(buf), 3)
+                enc_chunk, self._encoding_buffer = (buf[: div * 3], buf[div * 3 :])
+                if enc_chunk:
+                    b64chunk = base64.b64encode(enc_chunk)
+                    await self._writer.write(b64chunk)
+        elif self._encoding == "quoted-printable":
+            await self._writer.write(binascii.b2a_qp(chunk))
+        else:
+            await self._writer.write(chunk)