Method open

xarray/backends/h5netcdf_.py:172–265

(
        cls,
        filename,
        mode="r",
        format="NETCDF4",
        group=None,
        lock=None,
        autoclose=False,
        invalid_netcdf=None,
        phony_dims=None,
        decode_vlen_strings=True,
        driver=None,
        driver_kwds=None,
        storage_options: dict[str, Any] | None = None,
        open_kwargs: dict[str, Any] | None = None,
    )

    @classmethod
    def open(
        cls,
        filename,
        mode="r",
        format="NETCDF4",
        group=None,
        lock=None,
        autoclose=False,
        invalid_netcdf=None,
        phony_dims=None,
        decode_vlen_strings=True,
        driver=None,
        driver_kwds=None,
        storage_options: dict[str, Any] | None = None,
        open_kwargs: dict[str, Any] | None = None,
    ):
        import h5netcdf

        if isinstance(filename, str) and is_remote_uri(filename) and driver is None:
            mode_ = "rb" if mode == "r" else mode

            open_kwargs = open_kwargs or {}

            # Use blockcache with size 4MB by default
            if "cache_type" not in open_kwargs:
                open_kwargs["cache_type"] = "blockcache"
            if (
                open_kwargs["cache_type"] == "blockcache"
                and "block_size" not in open_kwargs
            ):
                open_kwargs["block_size"] = 4 * 1024 * 1024

            filename = _open_remote_file(
                filename,
                mode=mode_,
                storage_options=storage_options,
                open_kwargs=open_kwargs,
            )

        if isinstance(filename, BytesIOProxy):
            source = filename
            filename = io.BytesIO()
            source.getvalue = filename.getbuffer

        if isinstance(filename, io.IOBase) and mode == "r":
            magic_number = read_magic_number_from_file(filename)
            if not magic_number.startswith(b"\211HDF\r\n\032\n"):
                raise ValueError(
                    f"{magic_number!r} is not the signature of a valid netCDF4 file"
                )

        if format is None:
            format = "NETCDF4"

        if format not in ["NETCDF4", "NETCDF4_CLASSIC"]:
            raise ValueError(f"invalid format for h5netcdf backend: {format}")

        kwargs = {