import base64
import binascii
import json
import re
import uuid
import warnings
import zlib
from collections import deque
from types import TracebackType
from typing import ( # noqa
TYPE_CHECKING,
Any,
Dict,
Iterator,
List,
Mapping,
Optional,
Sequence,
Tuple,
Type,
Union,
cast,
)
from urllib.parse import parse_qsl, unquote, urlencode
from multidict import CIMultiDict, CIMultiDictProxy, MultiMapping # noqa
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
__all__ = ('MultipartReader', 'MultipartWriter', 'BodyPartReader',
'BadContentDispositionHeader', 'BadContentDispositionParam',
'parse_content_disposition', 'content_disposition_filename')
if TYPE_CHECKING: # pragma: no cover
from .client_reqrep import ClientResponse # noqa
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('\\\\([{}])'.format(chars), '\\1', text)
if not header:
return None, {}
disptype, *parts = header.split(';')
if not is_token(disptype):
warnings.warn(BadContentDispositionHeader(header))
return None, {}
params = {} # type: 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 = '%s;%s' % (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 MultipartBodyReader.
It takes care about
underlying connection and close it when it needs in.
"""
def __init__(self, resp: 'ClientResponse', stream: Any) -> None:
# TODO: add strong annotation to stream
self.resp = resp
self.stream = stream
def __aiter__(self) -> 'MultipartResponseWrapper':
return self
async def __anext__(self) -> Any:
part = await self.next()
if part is None:
raise StopAsyncIteration # NOQA
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) -> Any:
"""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:
"""Releases the connection gracefully, reading all the content
to the void."""
await self.resp.release()
class BodyPartReader:
"""Multipart reader for single body part."""
chunk_size = 8192
def __init__(self, boundary: bytes,
headers: Mapping[str, Optional[str]],
content: StreamReader) -> None:
self.headers = headers
self._boundary = boundary
self._content = content
self._at_eof = False
length = self.headers.get(CONTENT_LENGTH, None)
self._length = int(length) if length is not None else None
self._read_bytes = 0
# TODO: typeing.Deque is not supported by Python 3.5
self._unread = deque() # type: Any
self._prev_chunk = None # type: Optional[bytes]
self._content_eof = 0
self._cache = {} # type: Dict[str, Any]
def __aiter__(self) -> 'BodyPartReader':
return self
async def __anext__(self) -> Any:
part = await self.next()
if part is None:
raise StopAsyncIteration # NOQA
return part
async def next(self) -> Any:
item = await self.read()
if not item:
return None
return item
async def read(self, *, decode: bool=False) -> Any:
"""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)
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)
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 >= len(self._boundary) + 2, \
'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 = await self._content.read(size)
self._content_eof += int(self._content.at_eof())
assert self._content_eof < 3, "Reading after EOF"
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 # NOQA
# and https://dvcs.w3.org/hg/xhr/raw-file/tip/Overview.html#dom-xmlhttprequest-send # NOQA
encoding = encoding or self.get_charset(default='utf-8')
return data.decode(encoding)
async def json(self, *, encoding: Optional[str]=None) -> 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 json.loads(data.decode(encoding))
async def form(self, *,
encoding: Optional[str]=None) -> List[Tuple[str, str]]:
"""Like read(), but assumes that body parts contains 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')
return parse_qsl(data.rstrip().decode(real_encoding),
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 according the specified Content-Encoding
or Content-Transfer-Encoding headers value.
"""
if CONTENT_TRANSFER_ENCODING in self.headers:
data = self._decode_content_transfer(data)
if CONTENT_ENCODING in self.headers:
return self._decode_content(data)
return data
def _decode_content(self, data: bytes) -> bytes:
encoding = cast(str, self.headers[CONTENT_ENCODING]).lower()
if encoding == 'deflate':
return zlib.decompress(data, -zlib.MAX_WBITS)
elif encoding == 'gzip':
return zlib.decompress(data, 16 + zlib.MAX_WBITS)
elif encoding == 'identity':
return data
else:
raise RuntimeError('unknown content encoding: {}'.format(encoding))
def _decode_content_transfer(self, data: bytes) -> bytes:
encoding = cast(str, self.headers[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('unknown content transfer encoding: {}'
''.format(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', default)
@reify
def name(self) -> Optional[str]:
"""Returns name specified in Content-Disposition header or None
if missed or header is malformed.
"""
_, 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 or None
if missed or header is 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):
def __init__(self, value: BodyPartReader,
*args: Any, **kwargs: Any) -> None:
super().__init__(value, *args, **kwargs)
params = {} # type: 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)
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 = 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.headers = headers
self._boundary = ('--' + self._get_boundary()).encode()
self._content = content
self._last_part = None
self._at_eof = False
self._at_bof = True
self._unread = [] # type: List[bytes]
def __aiter__(self) -> 'MultipartReader':
return self
async def __anext__(self) -> Any:
part = await self.next()
if part is None:
raise StopAsyncIteration # NOQA
return part
@classmethod
def from_response(cls, response: 'ClientResponse') -> Any:
"""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 or
False otherwise.
"""
return self._at_eof
async def next(self) -> Any:
"""Emits the next multipart body part."""
# So, if we're at BOF, we need to skip till the boundary.
if self._at_eof:
return
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
self._last_part = await self.fetch_next_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) -> Any:
"""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]') -> Any:
"""Dispatches the response by the `Content-Type` header, returning
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)
def _get_boundary(self) -> str:
mimetype = parse_mimetype(self.headers[CONTENT_TYPE])
assert mimetype.type == 'multipart', (
'multipart/* content type expected'
)
if 'boundary' not in mimetype.parameters:
raise ValueError('boundary missed for Content-Type: %s'
% self.headers[CONTENT_TYPE])
boundary = 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('Invalid boundary %r, expected %r'
% (chunk, self._boundary))
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."""
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 = ('multipart/{}; boundary={}'
.format(subtype, self._boundary_value))
super().__init__(None, content_type=ctype)
self._parts = [] # type: List[_Part] # noqa
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)
_valid_tchar_regex = re.compile(br"\A[!#$%&'*+\-.^_`|~\w]+\Z")
_invalid_qdtext_char_regex = re.compile(br"[\x00-\x08\x0A-\x1F\x7F]")
@property
def _boundary_value(self) -> str:
"""Wrap boundary parameter value in quotes, if necessary.
Reads self.boundary and returns a unicode sting.
"""
# Refer to RFCs 7231, 7230, 5234.
#
# parameter = token "=" ( token / quoted-string )
# token = 1*tchar
# quoted-string = DQUOTE *( qdtext / quoted-pair ) DQUOTE
# qdtext = HTAB / SP / %x21 / %x23-5B / %x5D-7E / obs-text
# obs-text = %x80-FF
# quoted-pair = "\" ( HTAB / SP / VCHAR / obs-text )
# tchar = "!" / "#" / "$" / "%" / "&" / "'" / "*"
# / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
# / 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['MultiMapping[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."""
# compression
encoding = payload.headers.get(CONTENT_ENCODING, '').lower() # type: Optional[str] # noqa
if encoding and encoding not in ('deflate', 'gzip', 'identity'):
raise RuntimeError('unknown content encoding: {}'.format(encoding))
if encoding == 'identity':
encoding = None
# te encoding
te_encoding = payload.headers.get(
CONTENT_TRANSFER_ENCODING, '').lower() # type: Optional[str] # noqa
if te_encoding not in ('', 'base64', 'quoted-printable', 'binary'):
raise RuntimeError('unknown content transfer encoding: {}'
''.format(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
return payload
def append_json(
self,
obj: Any,
headers: Optional['MultiMapping[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['MultiMapping[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."""
if not self._parts:
return 0
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 + # b'--'+self._boundary+b'\r\n'
part.size + len(part._binary_headers) +
2 # b'\r\n'
)
total += 2 + len(self._boundary) + 4 # b'--'+self._boundary+b'--\r\n'
return total
async def write(self, writer: Any,
close_boundary: bool=True) -> None:
"""Write body."""
if not self._parts:
return
for part, encoding, te_encoding in self._parts:
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
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 = None # type: Optional[str]
self._compress = None # type: Any
self._encoding_buffer = None # type: Optional[bytearray]
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') -> None:
zlib_mode = (16 + zlib.MAX_WBITS
if encoding == 'gzip' else -zlib.MAX_WBITS)
self._compress = zlib.compressobj(wbits=zlib_mode)
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 = 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)
