243 lines
7.4 KiB
Python
243 lines
7.4 KiB
Python
"""MIT License
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Copyright (c) 2023 - present Vocard Development
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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"""
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from __future__ import annotations
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import base64, io, abc, struct, dataclasses
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from typing import Union, BinaryIO, Optional, TYPE_CHECKING
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if TYPE_CHECKING:
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from .objects import Track
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@dataclasses.dataclass(frozen=True)
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class Codec:
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encoding: str
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error_handler: str
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def encode(self, data: str) -> bytes:
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return data.encode(self.encoding, self.error_handler)
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def decode(self, data: bytes) -> str:
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return data.decode(self.encoding, self.error_handler)
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UTF8 = Codec("utf-8", "surrogatepass")
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_FORMAT_BOOL = "?"
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_FORMAT_BYTE = "b"
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_FORMAT_INT = ">i"
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_FORMAT_LONG = ">q"
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_FORMAT_USHORT = ">H"
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class HasStream(abc.ABC):
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@property
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@abc.abstractmethod
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def stream(self) -> BinaryIO:
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...
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class Reader(HasStream):
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def __init__(self, stream: Union[BinaryIO, HasStream]) -> None:
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self._stream: BinaryIO = stream.stream if isinstance(stream, HasStream) else stream
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@property
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def stream(self) -> BinaryIO:
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return self._stream
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def read_bool(self) -> bool:
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return struct.unpack(_FORMAT_BOOL, self._stream.read(1))[0]
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def read_byte(self) -> int:
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return struct.unpack(_FORMAT_BYTE, self._stream.read(1))[0]
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def read_int(self) -> int:
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return struct.unpack(_FORMAT_INT, self._stream.read(4))[0]
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def read_long(self) -> int:
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return struct.unpack(_FORMAT_LONG, self._stream.read(8))[0]
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def read_ushort(self) -> int:
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return struct.unpack(_FORMAT_USHORT, self._stream.read(2))[0]
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def read_utf(self) -> str:
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length = self.read_ushort()
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data = self._stream.read(length)
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return UTF8.decode(data)
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def read_optional_utf(self) -> Optional[str]:
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if self.read_bool():
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return self.read_utf()
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else:
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return None
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class Writer:
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_stream: BinaryIO
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def __init__(self, stream: Union[BinaryIO, HasStream] = None ) -> None:
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if stream is None:
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stream = io.BytesIO()
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elif isinstance(stream, HasStream):
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stream = stream.stream
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self._stream = stream
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self._string_codec: Codec = UTF8
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@property
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def stream(self) -> BinaryIO:
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return self._stream
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def write_bool(self, data: bool) -> None:
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self._stream.write(struct.pack(_FORMAT_BOOL, data))
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def write_byte(self, data: int) -> None:
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self._stream.write(struct.pack(_FORMAT_BYTE, data))
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def write_int(self, data: int) -> None:
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self._stream.write(struct.pack(_FORMAT_INT, data))
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def write_long(self, data: int) -> None:
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self._stream.write(struct.pack(_FORMAT_LONG, data))
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def write_ushort(self, data: int) -> None:
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self._stream.write(struct.pack(_FORMAT_USHORT, data))
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def write_utf(self, data: str) -> None:
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data = self._string_codec.encode(data)
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self.write_ushort(len(data))
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self._stream.write(data)
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def write_optional_utf(self, data: Optional[str]) -> None:
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if data is None:
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self.write_bool(False)
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else:
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self.write_bool(True)
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self.write_utf(data)
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class MessageInput(HasStream):
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def __init__(self, stream: Union[BinaryIO, HasStream]) -> None:
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self._stream: Reader = Reader(stream)
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self._flags: int = 0
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self._size: int = 0
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@property
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def stream(self) -> BinaryIO:
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return self._stream.stream
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@property
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def flags(self) -> int:
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return self._flags
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def next(self) -> Optional[Reader]:
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value = self._stream.read_int()
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self._flags = (value & 0xC0000000) >> 30
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self._size = value & 0x3FFFFFFF
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if not self._size:
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return None
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data = self._stream.stream.read(self._size)
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return Reader(io.BytesIO(data))
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class MessageOutput(HasStream):
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_stream: Writer
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_body_stream: io.BytesIO
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def __init__(self, stream: Union[BinaryIO, HasStream]) -> None:
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self._string_codec: Codec = UTF8
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self._stream = Writer(stream)
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self._body_stream = io.BytesIO()
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@property
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def stream(self) -> BinaryIO:
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return self._stream.stream
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def start(self) -> Writer:
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self._body_stream.truncate(0)
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self._body_stream.seek(0)
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return Writer(self._body_stream)
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def commit(self, flags: int = None) -> None:
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data = self._body_stream.getvalue()
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header = len(data)
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if flags:
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header |= flags << 30
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self._stream.write_int(header)
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self._stream.stream.write(data)
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def finish(self) -> None:
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self._stream.write_int(0)
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class TrackDecoder:
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"""TrackDecoder for track messages."""
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def decode(self, stream: MessageInput):
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"""Decode an entire message and return the `Track`."""
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body_reader = stream.next()
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if not body_reader:
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raise ValueError("empty stream")
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version = body_reader.read_byte()
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return {
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"title": body_reader.read_utf(),
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"author": body_reader.read_utf(),
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"length": body_reader.read_long(),
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"identifier": body_reader.read_utf(),
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"is_stream": body_reader.read_bool(),
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"uri": body_reader.read_optional_utf(),
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"artworkUrl": None if version not in [0, 3] else body_reader.read_optional_utf(),
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"isrc": None if version != 3 else body_reader.read_optional_utf(),
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"sourceName": body_reader.read_utf(),
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"position": body_reader.read_long()
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}
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class TrackEncoder:
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def encode(self, stream: MessageOutput, track: Track) -> None:
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body_writer = stream.start()
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body_writer.write_byte(0)
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body_writer.write_utf(track.title)
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body_writer.write_utf(track.author)
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body_writer.write_long(track.length)
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body_writer.write_utf(track.identifier)
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body_writer.write_bool(track.is_stream)
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body_writer.write_optional_utf(track.uri)
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body_writer.write_optional_utf(track.thumbnail)
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body_writer.write_utf(track.source)
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body_writer.write_long(0)
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stream.commit()
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def decode(data: Union[str, bytes]) -> dict:
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decoded = base64.b64decode(data)
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stream = MessageInput(io.BytesIO(decoded))
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return TrackDecoder().decode(stream)
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def encode(track) -> bytes:
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buf = io.BytesIO()
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stream = MessageOutput(buf)
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TrackEncoder().encode(stream, track)
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return base64.b64encode(buf.getvalue()).decode("utf-8")
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