Method readline

Lib/asyncio/streams.py:543–572

Read chunk of data from the stream until newline (b'\n') is found. On success, return chunk that ends with newline. If only partial line can be read due to EOF, return incomplete line without terminating newline. When EOF was reached while no bytes read, empty bytes

(self)

            self._waiter = None

    async def readline(self):
        """Read chunk of data from the stream until newline (b'\n') is found.

        On success, return chunk that ends with newline. If only partial
        line can be read due to EOF, return incomplete line without
        terminating newline. When EOF was reached while no bytes read, empty
        bytes object is returned.

        If limit is reached, ValueError will be raised. In that case, if
        newline was found, complete line including newline will be removed
        from internal buffer. Else, internal buffer will be cleared. Limit is
        compared against part of the line without newline.

        If stream was paused, this function will automatically resume it if
        needed.
        """
        sep = b'\n'
        seplen = len(sep)
        try:
            line = await self.readuntil(sep)
        except exceptions.IncompleteReadError as e:
            return e.partial
        except exceptions.LimitOverrunError as e:
            if self._buffer.startswith(sep, e.consumed):
                del self._buffer[:e.consumed + seplen]
            else:
                self._buffer.clear()
            self._maybe_resume_transport()
            raise ValueError(e.args[0])
        return line

    async def readuntil(self, separator=b'\n'):
        """Read data from the stream until ``separator`` is found.