Class Task

pywebio/session/coroutinebased.py:268–378

class Task:

    @contextmanager
    def session_context(self):
        """
        >>> with session_context():
        ...     res = self.coros[-1].send(data)
        """

        # todo issue: with 语句可能发生嵌套，导致内层with退出时，将属性置空
        _context.current_session = self.session
        _context.current_task_id = self.coro_id
        try:
            yield
        finally:
            _context.current_session = None
            _context.current_task_id = None

    @staticmethod
    def gen_coro_id(coro=None):
        """生成协程id"""
        name = 'coro'
        if hasattr(coro, '__name__'):
            name = coro.__name__

        return '%s-%s' % (name, random_str(10))

    def __init__(self, coro, session: CoroutineBasedSession, on_coro_stop=None):
        """
        :param coro: 协程对象
        :param session: 创建该Task的会话实例
        :param on_coro_stop: 任务结束(正常结束或外部调用Task.close)时运行的回调
        """
        self.session = session
        self.coro = coro
        self.result = None
        self.task_closed = False  # 任务完毕/取消
        self.on_coro_stop = on_coro_stop or (lambda _: None)

        self.coro_id = self.gen_coro_id(self.coro)

        self.pending_futures = {}  # id(future) -> future

        logger.debug('Task[%s] created ', self.coro_id)

    def step(self, result=None, throw_exp=False):
        """激活协程

        :param any result: 向协程传入的数据
        :param bool throw_exp: 是否向协程引发异常，为 True 时， result 参数为相应的异常对象
        """
        coro_yield = None
        with self.session_context():
            try:
                if throw_exp:
                    coro_yield = self.coro.throw(result)
                else:
                    coro_yield = self.coro.send(result)