/
trio.py
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/
trio.py
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from ssl import SSLContext
from typing import Optional
import trio
from .._exceptions import (
CloseError,
ConnectError,
ConnectTimeout,
ReadError,
ReadTimeout,
WriteError,
WriteTimeout,
map_exceptions,
)
from .._types import TimeoutDict
from .base import AsyncBackend, AsyncLock, AsyncSemaphore, AsyncSocketStream
def none_as_inf(value: Optional[float]) -> float:
return value if value is not None else float("inf")
class SocketStream(AsyncSocketStream):
def __init__(self, stream: trio.abc.Stream) -> None:
self.stream = stream
self.read_lock = trio.Lock()
self.write_lock = trio.Lock()
def get_http_version(self) -> str:
if not isinstance(self.stream, trio.SSLStream):
return "HTTP/1.1"
ident = self.stream.selected_alpn_protocol()
return "HTTP/2" if ident == "h2" else "HTTP/1.1"
async def start_tls(
self, hostname: bytes, ssl_context: SSLContext, timeout: TimeoutDict
) -> "SocketStream":
connect_timeout = none_as_inf(timeout.get("connect"))
exc_map = {
trio.TooSlowError: ConnectTimeout,
trio.BrokenResourceError: ConnectError,
}
ssl_stream = trio.SSLStream(
self.stream,
ssl_context=ssl_context,
server_hostname=hostname.decode("ascii"),
)
with map_exceptions(exc_map):
with trio.fail_after(connect_timeout):
await ssl_stream.do_handshake()
return SocketStream(ssl_stream)
async def read(self, n: int, timeout: TimeoutDict) -> bytes:
read_timeout = none_as_inf(timeout.get("read"))
exc_map = {trio.TooSlowError: ReadTimeout, trio.BrokenResourceError: ReadError}
async with self.read_lock:
with map_exceptions(exc_map):
with trio.fail_after(read_timeout):
return await self.stream.receive_some(max_bytes=n)
async def write(self, data: bytes, timeout: TimeoutDict) -> None:
if not data:
return
write_timeout = none_as_inf(timeout.get("write"))
exc_map = {
trio.TooSlowError: WriteTimeout,
trio.BrokenResourceError: WriteError,
}
async with self.write_lock:
with map_exceptions(exc_map):
with trio.fail_after(write_timeout):
return await self.stream.send_all(data)
async def aclose(self) -> None:
async with self.write_lock:
with map_exceptions({trio.BrokenResourceError: CloseError}):
await self.stream.aclose()
def is_readable(self) -> bool:
# Adapted from: https://github.com/encode/httpx/pull/143#issuecomment-515202982
stream = self.stream
# Peek through any SSLStream wrappers to get the underlying SocketStream.
while isinstance(stream, trio.SSLStream):
stream = stream.transport_stream
assert isinstance(stream, trio.SocketStream)
return stream.socket.is_readable()
class Lock(AsyncLock):
def __init__(self) -> None:
self._lock = trio.Lock()
async def release(self) -> None:
self._lock.release()
async def acquire(self) -> None:
await self._lock.acquire()
class Semaphore(AsyncSemaphore):
def __init__(self, max_value: int, exc_class: type):
self.max_value = max_value
self.exc_class = exc_class
@property
def semaphore(self) -> trio.Semaphore:
if not hasattr(self, "_semaphore"):
self._semaphore = trio.Semaphore(self.max_value, max_value=self.max_value)
return self._semaphore
async def acquire(self, timeout: float = None) -> None:
timeout = none_as_inf(timeout)
with trio.move_on_after(timeout):
await self.semaphore.acquire()
return
raise self.exc_class()
async def release(self) -> None:
self.semaphore.release()
class TrioBackend(AsyncBackend):
async def open_tcp_stream(
self,
hostname: bytes,
port: int,
ssl_context: Optional[SSLContext],
timeout: TimeoutDict,
*,
local_address: Optional[str],
) -> AsyncSocketStream:
connect_timeout = none_as_inf(timeout.get("connect"))
# Trio will support local_address from 0.16.1 onwards.
# We only include the keyword argument if a local_address
# argument has been passed.
kwargs: dict = {} if local_address is None else {"local_address": local_address}
exc_map = {
trio.TooSlowError: ConnectTimeout,
trio.BrokenResourceError: ConnectError,
}
with map_exceptions(exc_map):
with trio.fail_after(connect_timeout):
stream: trio.abc.Stream = await trio.open_tcp_stream(
hostname, port, **kwargs
)
if ssl_context is not None:
stream = trio.SSLStream(
stream, ssl_context, server_hostname=hostname.decode("ascii")
)
await stream.do_handshake()
return SocketStream(stream=stream)
async def open_uds_stream(
self,
path: str,
hostname: bytes,
ssl_context: Optional[SSLContext],
timeout: TimeoutDict,
) -> AsyncSocketStream:
connect_timeout = none_as_inf(timeout.get("connect"))
exc_map = {
trio.TooSlowError: ConnectTimeout,
trio.BrokenResourceError: ConnectError,
}
with map_exceptions(exc_map):
with trio.fail_after(connect_timeout):
stream: trio.abc.Stream = await trio.open_unix_socket(path)
if ssl_context is not None:
stream = trio.SSLStream(
stream, ssl_context, server_hostname=hostname.decode("ascii")
)
await stream.do_handshake()
return SocketStream(stream=stream)
def create_lock(self) -> AsyncLock:
return Lock()
def create_semaphore(self, max_value: int, exc_class: type) -> AsyncSemaphore:
return Semaphore(max_value, exc_class=exc_class)
async def time(self) -> float:
return trio.current_time()
async def sleep(self, seconds: float) -> None:
await trio.sleep(seconds)