Class MultipartStream

httpx/_multipart.py:224–300

Request content as streaming multipart encoded form data.

class MultipartStream(SyncByteStream, AsyncByteStream):
    """
    Request content as streaming multipart encoded form data.
    """

    def __init__(
        self,
        data: RequestData,
        files: RequestFiles,
        boundary: bytes | None = None,
    ) -> None:
        if boundary is None:
            boundary = os.urandom(16).hex().encode("ascii")

        self.boundary = boundary
        self.content_type = "multipart/form-data; boundary=%s" % boundary.decode(
            "ascii"
        )
        self.fields = list(self._iter_fields(data, files))

    def _iter_fields(
        self, data: RequestData, files: RequestFiles
    ) -> typing.Iterator[FileField | DataField]:
        for name, value in data.items():
            if isinstance(value, (tuple, list)):
                for item in value:
                    yield DataField(name=name, value=item)
            else:
                yield DataField(name=name, value=value)

        file_items = files.items() if isinstance(files, typing.Mapping) else files
        for name, value in file_items:
            yield FileField(name=name, value=value)

    def iter_chunks(self) -> typing.Iterator[bytes]:
        for field in self.fields:
            yield b"--%s\r\n" % self.boundary
            yield from field.render()
            yield b"\r\n"
        yield b"--%s--\r\n" % self.boundary

    def get_content_length(self) -> int | None:
        """
        Return the length of the multipart encoded content, or `None` if
        any of the files have a length that cannot be determined upfront.
        """
        boundary_length = len(self.boundary)
        length = 0

        for field in self.fields:
            field_length = field.get_length()
            if field_length is None:
                return None

            length += 2 + boundary_length + 2  # b"--{boundary}\r\n"
            length += field_length
            length += 2  # b"\r\n"