修复断网重连以后录制无法自动恢复的问题

[imkero]

Fix #259

问题现象

断网触发 ConnectionErrorHandler 后：

• 若网络恢复，会报错 aiohttp.client_exceptions.ClientResponseError: 412, message='Precondition Failed', url=URL('https://live.bilibili.com/')，
• 若网络一直未恢复，断网等待时间 设置项不生效

问题原因

1. Live 中 check_connectivity 方法未捕获所有异常，若请求 https://live.bilibili.com/ 失败，会导致异常抛出到 ConnectionErrorHandler 的 _wait_for_connection_error 导致重试与超时逻辑被打断

   blrec/src/blrec/bili/live.py

   Lines 173 to 179 in 8dc32e5

   	async def check_connectivity(self) -> bool:
   	try:
   	await self._session.head('https://live.bilibili.com/', timeout=3)
   	except (aiohttp.ClientConnectionError, asyncio.TimeoutError):
   	return False
   	else:
   	return True

   blrec/src/blrec/core/operators/connection_error_handler.py

   Lines 74 to 85 in 8dc32e5

   	def _wait_for_connection_error(self) -> bool:
   	timeout = self.disconnection_timeout
   	logger.info(f'Waiting {timeout} seconds for connection recovery... ')
   	timebase = time.monotonic()
   	while not self._call_coroutine(self._live.check_connectivity()):
   	if timeout is not None and time.monotonic() - timebase > timeout:
   	logger.error(f'Connection not recovered in {timeout} seconds')
   	return False
   	time.sleep(self.check_interval)
   	else:
   	logger.info('Connection recovered')
   	return True

2. Live 中 check_connectivity 方法请求的 B 站直播首页 https://live.bilibili.com/ 有风控策略，当请求 UA 为 python requests 的 UA（例如 python-requests/2.31.0）时，会拦截并返回 412 状态码，导致 check_connectivity 始终不能成功

   curl -v -H "User-Agent: python-requests/2.31.0" https://live.bilibili.com/
   

   > GET / HTTP/1.1
   > Host: live.bilibili.com
   > Accept: */*
   > User-Agent: python-requests/2.31.0
   >
   
   < HTTP/1.1 412 Precondition Failed
   < Content-Type: text/html
   < Transfer-Encoding: chunked
   < Connection: keep-alive
   < Server: openresty
   < Cache-Control: no-cache
   < X-BILI-SEC-TOKEN: 1,denied by waf mode
   <
   

修复方法

1. check_connectivity 请求 https://live.bilibili.com/ 时带上用户指定的 UA
2. check_connectivity 捕获 requests 请求时抛出的所有异常，若有异常则返回 False 并打印异常信息到 log 当中