async_client.py

''' Asynchronous python bindings for the lircd socket interface. '''

 

 
#   pylint: disable=W0613
 
import asyncio
from lirc.client import AbstractConnection as AbstractConnection
 
 
class AsyncConnection(object):
    ''' Asynchronous read interface on top of an AbstractConnection.
 
    Parameters:
       - connection: Typically a lirc.RawConnection or lirc.LircdConnection.
       - loop: AbstractEventLoop, typically obtained using
               asyncio.get_event_loop().
    '''
 
    def __init__(self, connection: AbstractConnection,
                 loop: asyncio.AbstractEventLoop):
 
        def read_from_fd():
            ''' Read data from the connection fd and put into queue. '''
            try:
                line = self._conn.readline(0)
                if line:
                    asyncio.ensure_future(self._queue.put(line))
            except Exception as e:
                self.close()
                self._queue.put_nowait(e)
 
        self._conn = connection
        self._loop = loop
        self._queue = asyncio.Queue()
        self._loop.add_reader(self._conn.fileno(), read_from_fd)
 
    def close(self):
        ''' Clean up loop and the base connection. '''
        self._loop.remove_reader(self._conn.fileno())
 
    async def readline(self) -> str:
        ''' Asynchronous get next line from the connection. '''
        line = await self._queue.get()
        if isinstance(line, Exception):
            raise line
        return line
 
    def __aiter__(self):
        ''' Return async iterator. '''
        return self
 
    async def __anext__(self):
        ''' Implement async iterator.next(). '''
        line = await self._queue.get()
        if isinstance(line, Exception):
            raise StopAsyncIteration
        return line
 
    async def __aenter__(self):
        ''' Implement "async with". '''
        return self
 
    async def __aexit__(self, exc_type, exc, traceback):
        ''' Implement exit from "async with". '''
        self.close()