Class FormData

aiohttp/formdata.py:17–184

Helper class for form body generation. Supports multipart/form-data and application/x-www-form-urlencoded.

class FormData:
    """Helper class for form body generation.

    Supports multipart/form-data and application/x-www-form-urlencoded.
    """

    def __init__(
        self,
        fields: Iterable[Any] = (),
        quote_fields: bool = True,
        charset: str | None = None,
        *,
        default_to_multipart: bool = False,
    ) -> None:
        self._writer = multipart.MultipartWriter("form-data")
        self._fields: list[Any] = []
        self._is_multipart = default_to_multipart
        self._quote_fields = quote_fields
        self._charset = charset

        if isinstance(fields, dict):
            fields = list(fields.items())
        elif not isinstance(fields, (list, tuple)):
            fields = (fields,)
        self.add_fields(*fields)

    @property
    def is_multipart(self) -> bool:
        return self._is_multipart

    def add_field(
        self,
        name: str,
        value: Any,
        *,
        content_type: str | None = None,
        filename: str | None = None,
        content_transfer_encoding: str | None = None,
    ) -> None:

        if isinstance(value, io.IOBase):
            self._is_multipart = True
        elif isinstance(value, (bytes, bytearray, memoryview)):
            msg = (
                "In v4, passing bytes will no longer create a file field. "
                "Please explicitly use the filename parameter or pass a BytesIO object."
            )
            if filename is None and content_transfer_encoding is None:
                warnings.warn(msg, DeprecationWarning)
                filename = name

        _safe_header(name)
        type_options: MultiDict[str] = MultiDict({"name": name})
        if filename is not None and not isinstance(filename, str):
            raise TypeError("filename must be an instance of str. Got: %s" % filename)
        if filename is None and isinstance(value, io.IOBase):
            filename = guess_filename(value, name)
        if filename is not None: