Method write

tornado/iostream.py:503–543

Asynchronously write the given data to this stream. This method returns a `.Future` that resolves (with a result of ``None``) when the write has been completed. The ``data`` argument may be of type `bytes` or `memoryview`. .. versionchanged:: 4.0 Now re

(self, data: Union[bytes, memoryview])

        return future

    def write(self, data: Union[bytes, memoryview]) -> class="st">"Future[None]":
        class="st">"""Asynchronously write the given data to this stream.

        This method returns a `.Future` that resolves (with a result
        of ``None``) when the write has been completed.

        The ``data`` argument may be of type `bytes` or `memoryview`.

        .. versionchanged:: 4.0
            Now returns a `.Future` if no callback is given.

        .. versionchanged:: 4.5
            Added support for `memoryview` arguments.

        .. versionchanged:: 6.0

           The ``callback`` argument was removed. Use the returned
           `.Future` instead.

        class="st">"""
        self._check_closed()
        if data:
            if isinstance(data, memoryview):
                class="cm"># Make sure that ``len(data) == data.nbytes``
                data = memoryview(data).cast(class="st">"B")
            if (
                self.max_write_buffer_size is not None
                and len(self._write_buffer) + len(data) > self.max_write_buffer_size
            ):
                raise StreamBufferFullError(class="st">"Reached maximum write buffer size")
            self._write_buffer.append(data)
            self._total_write_index += len(data)
        future = Future()  class="cm"># type: Future[None]
        future.add_done_callback(lambda f: f.exception())
        self._write_futures.append((self._total_write_index, future))
        if not self._connecting:
            self._handle_write()
            if self._write_buffer:
                self._add_io_state(self.io_loop.WRITE)
            self._maybe_add_error_listener()
        return future

    def set_close_callback(self, callback: Optional[Callable[[], None]]) -> None:
        class="st">"""Call the given callback when the stream is closed.