>>> import serial
>>> # Open named port at “19200,8,N,1”, 1s timeout:
>>> with serial.Serial('/dev/ttyS1', 19200, timeout=1) as ser:
...     x = ser.read()          # read one byte
...     s = ser.read(10)        # read up to ten bytes (timeout)
...     line = ser.readline()   # read a '\n' terminated line


>>> # Open port at “38400,8,E,1”, non blocking HW handshaking:
>>> ser = serial.Serial('COM3', 38400, timeout=0,
...                     parity=serial.PARITY_EVEN, rtscts=1)
>>> s = ser.read(100)       # read up to one hundred bytes
...                         # or as much is in the buffer

def consumer():
    with serial.Serial(com, port, timeout=0) as ser:
        buffer = ''
        while True:
            buffer += ser.readline().decode()
            if '\r' in buffer:
                buf = buffer.split('\r')
                last_received, buffer = buffer.split('\r')[-2:]
                yield last_received


async def async_producer(session, q):
    start = time.time()
    while len(q):
        data = q.popleft()
        status, result = await async_post(session, url_seq, url_films, data)
        
        if status != 201:
            q.append(data)
        
        if time.time() - start >= 1:
            break

q = deque()
com = 'COM5'
port = 9600
last_received = ''

async def async_main():
    global q
    async with aiohttp.ClientSession() as session:
        for data in consumer():
            q.append(data)
            
            d = q.popleft()
            status, result = await async_post(session, url_seq, url_films, data=d) # post data
            if status != 201:
                q.append(d)
            
            if len(q) >= 2:
                await async_producer(session, q)

loop = asyncio.get_event_loop()
loop.run_until_complete(async_main())
loop.close()

async def async_main():
    global q  # --> 錯誤 (1)
    async with aiohttp.ClientSession() as session:
        for data in consumer():  # --> 錯誤 (2) 
            q.append(data)
            
            d = q.popleft()
            status, result = await async_post(session, url_seq, url_films, data=d) # post data
            if status != 201:
                q.append(d)
            
            if len(q) >= 2:
                await async_producer(session, q)

loop = asyncio.get_event_loop()
loop.run_until_complete(async_main())
loop.close()

# 'read', 'readexactly', 'readuntil', or 'readline'
msg = await r.readuntil(b'\r')

async def consume(queue):
    """Get serail data with async"""
    while True:
        data = await queue.get()
        print(f'consuming: {id(data)}')
        """handle data from here"""
        await asyncio.sleep(random.random())
        queue.task_done()


loop = asyncio.get_event_loop()
queue = asyncio.Queue(loop=loop)

produce = partial(Reader, queue)
producer_coro = serial_asyncio.create_serial_connection(
    loop, produce, com, baudrate
)
consumer_coro = consume(queue)
loop.run_until_complete(asyncio.gather(producer_coro, consumer_coro))
loop.close()

>>> buf = buf.rstrip().decode('utf-8')
>>> UnicodeDecodeError: 'utf-8' codec can't decode byte 0xe0 in position 0: invalid 
continuation byte

Task was destroyed but it is pending!
task: <Task pending coro=<consume() running at xxxxx.py:207> 
wait_for=<Future pending cb=[<TaskWakeupMethWrapper object at 0x03144F30>()]>>
2018-09-04 08:24:31 INFO  [xxxxx:216] Event loop is closed
Exception ignored in: <coroutine object consume at 0x03255660>
RuntimeError: coroutine ignored GeneratorExit

try:
    buf = buf.rstrip().decode('utf-8')
except Exception as e:
    wlog(buf)
    buf = buf.rstrip().decode('utf-8', 'ignore')

import pytz


# 要查詢資料庫的時間記得要加上時區
tp = pytz.timezone('Asia/Taipei')
dt = datetime.datetime.strptime(start, '%Y-%m-%d %H:%M').astimezone(tp)