223 lines
6.4 KiB
Python
223 lines
6.4 KiB
Python
# MicroPython asyncio module
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# MIT license; Copyright (c) 2019-2020 Damien P. George
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from . import core
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class Stream:
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def __init__(self, s, e={}):
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self.s = s
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self.e = e
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self.out_buf = b""
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def get_extra_info(self, v):
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return self.e[v]
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def close(self):
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pass
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async def wait_closed(self):
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# TODO yield?
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self.s.close()
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# async
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def read(self, n=-1):
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r = b""
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while True:
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yield core._io_queue.queue_read(self.s)
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r2 = self.s.read(n)
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if r2 is not None:
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if n >= 0:
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return r2
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if not len(r2):
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return r
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r += r2
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# async
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def readinto(self, buf):
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yield core._io_queue.queue_read(self.s)
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return self.s.readinto(buf)
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# async
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def readexactly(self, n):
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r = b""
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while n:
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yield core._io_queue.queue_read(self.s)
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r2 = self.s.read(n)
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if r2 is not None:
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if not len(r2):
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raise EOFError
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r += r2
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n -= len(r2)
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return r
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# async
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def readline(self):
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l = b""
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while True:
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yield core._io_queue.queue_read(self.s)
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l2 = self.s.readline() # may do multiple reads but won't block
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if l2 is None:
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continue
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l += l2
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if not l2 or l[-1] == 10: # \n (check l in case l2 is str)
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return l
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def write(self, buf):
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if not self.out_buf:
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# Try to write immediately to the underlying stream.
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ret = self.s.write(buf)
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if ret == len(buf):
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return
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if ret is not None:
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buf = buf[ret:]
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self.out_buf += buf
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# async
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def drain(self):
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if not self.out_buf:
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# Drain must always yield, so a tight loop of write+drain can't block the scheduler.
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return (yield from core.sleep_ms(0))
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mv = memoryview(self.out_buf)
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off = 0
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while off < len(mv):
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yield core._io_queue.queue_write(self.s)
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ret = self.s.write(mv[off:])
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if ret is not None:
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off += ret
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self.out_buf = b""
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# Stream can be used for both reading and writing to save code size
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StreamReader = Stream
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StreamWriter = Stream
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# Create a TCP stream connection to a remote host
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#
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# async
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def open_connection(host, port, ssl=None, server_hostname=None):
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from errno import EINPROGRESS
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import socket
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ai = socket.getaddrinfo(host, port, 0, socket.SOCK_STREAM)[0] # TODO this is blocking!
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s = socket.socket(ai[0], ai[1], ai[2])
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s.setblocking(False)
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try:
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s.connect(ai[-1])
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except OSError as er:
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if er.errno != EINPROGRESS:
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raise er
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# wrap with SSL, if requested
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if ssl:
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if ssl is True:
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import ssl as _ssl
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ssl = _ssl.SSLContext(_ssl.PROTOCOL_TLS_CLIENT)
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if not server_hostname:
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server_hostname = host
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s = ssl.wrap_socket(s, server_hostname=server_hostname, do_handshake_on_connect=False)
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s.setblocking(False)
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ss = Stream(s)
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yield core._io_queue.queue_write(s)
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return ss, ss
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# Class representing a TCP stream server, can be closed and used in "async with"
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class Server:
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async def __aenter__(self):
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return self
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async def __aexit__(self, exc_type, exc, tb):
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self.close()
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await self.wait_closed()
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def close(self):
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# Note: the _serve task must have already started by now due to the sleep
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# in start_server, so `state` won't be clobbered at the start of _serve.
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self.state = True
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self.task.cancel()
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async def wait_closed(self):
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await self.task
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async def _serve(self, s, cb, ssl):
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self.state = False
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# Accept incoming connections
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while True:
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try:
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yield core._io_queue.queue_read(s)
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except core.CancelledError as er:
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# The server task was cancelled, shutdown server and close socket.
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s.close()
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if self.state:
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# If the server was explicitly closed, ignore the cancellation.
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return
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else:
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# Otherwise e.g. the parent task was cancelled, propagate
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# cancellation.
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raise er
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try:
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s2, addr = s.accept()
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except:
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# Ignore a failed accept
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continue
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if ssl:
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try:
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s2 = ssl.wrap_socket(s2, server_side=True, do_handshake_on_connect=False)
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except OSError as e:
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core.sys.print_exception(e)
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s2.close()
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continue
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s2.setblocking(False)
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s2s = Stream(s2, {"peername": addr})
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core.create_task(cb(s2s, s2s))
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# Helper function to start a TCP stream server, running as a new task
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# TODO could use an accept-callback on socket read activity instead of creating a task
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async def start_server(cb, host, port, backlog=5, ssl=None):
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import socket
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# Create and bind server socket.
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host = socket.getaddrinfo(host, port)[0] # TODO this is blocking!
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s = socket.socket()
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s.setblocking(False)
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s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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s.bind(host[-1])
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s.listen(backlog)
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# Create and return server object and task.
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srv = Server()
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srv.task = core.create_task(srv._serve(s, cb, ssl))
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try:
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# Ensure that the _serve task has been scheduled so that it gets to
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# handle cancellation.
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await core.sleep_ms(0)
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except core.CancelledError as er:
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# If the parent task is cancelled during this first sleep, then
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# we will leak the task and it will sit waiting for the socket, so
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# cancel it.
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srv.task.cancel()
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raise er
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return srv
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################################################################################
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# Legacy uasyncio compatibility
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async def stream_awrite(self, buf, off=0, sz=-1):
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if off != 0 or sz != -1:
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buf = memoryview(buf)
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if sz == -1:
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sz = len(buf)
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buf = buf[off : off + sz]
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self.write(buf)
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await self.drain()
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Stream.aclose = Stream.wait_closed
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Stream.awrite = stream_awrite
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Stream.awritestr = stream_awrite # TODO explicitly convert to bytes?
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