初步开发了新的pymsg,并且应用在了dnfs上面

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qing committed 2026-07-26 17:57:27 +08:00
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"""pymsg - Length-prefixed variable-length socket message framing.
Protocol: [4-byte big-endian uint32 length][UTF-8 payload]
Usage:
import socket
from pymsg import send, recv
# sender
send(sock, "hello world")
# receiver
msg = recv(sock)
# with timeout (seconds)
send(sock, "hello", timeout=5.0)
msg = recv(sock, timeout=5.0)
"""
import contextlib
import select
import socket as _socket
import struct
__all__ = ["send", "recv", "TimeoutError", "MsgClient", "MsgServer"]
_HEADER = struct.Struct("!I") # 4 bytes, big-endian unsigned int
class TimeoutError(Exception):
"""Raised when a send or recv operation exceeds its timeout."""
@contextlib.contextmanager
def _timeout(sock: "_socket.socket", seconds: "float | None"):
"""Temporarily set the socket timeout, restoring it on exit."""
if seconds is None:
yield
return
original = sock.gettimeout()
sock.settimeout(seconds)
try:
yield
finally:
sock.settimeout(original)
def send(
sock: "_socket.socket",
data: str,
*,
timeout: "float | None" = None,
) -> None:
"""Send a string over a socket using length-prefixed framing.
Args:
sock: A connected socket object.
data: The string message to send.
timeout: Optional timeout in seconds. Raises TimeoutError on expiry.
"""
payload = data.encode("utf-8")
header = _HEADER.pack(len(payload))
with _timeout(sock, timeout):
try:
sock.sendall(header + payload)
except _socket.timeout:
raise TimeoutError(
f"send timed out after {timeout}s"
) from None
def recv(
sock: "_socket.socket",
*,
timeout: "float | None" = None,
) -> str:
"""Receive a length-prefixed string message from a socket.
Args:
sock: A connected socket object.
timeout: Optional timeout in seconds. Raises TimeoutError on expiry.
Returns:
The decoded string message.
Raises:
ConnectionError: If the connection is closed before a complete
message is received.
TimeoutError: If the operation exceeds the timeout.
"""
with _timeout(sock, timeout):
try:
header = _recv_exact(sock, _HEADER.size)
(length,) = _HEADER.unpack(header)
payload = _recv_exact(sock, length)
return payload.decode("utf-8")
except _socket.timeout:
raise TimeoutError(
f"recv timed out after {timeout}s"
) from None
def _recv_exact(sock: "_socket.socket", n: int) -> bytes:
"""Read exactly n bytes from sock, raising on premature close."""
buf = bytearray()
while len(buf) < n:
chunk = sock.recv(n - len(buf))
if not chunk:
raise ConnectionError(
f"connection closed: expected {n} bytes, got {len(buf)}"
)
buf.extend(chunk)
return bytes(buf)
# ---------------------------------------------------------------------------
# 高层类:封装基于 pymsg 的客户端 / 服务器
# ---------------------------------------------------------------------------
class MsgClient:
"""TCP 聊天客户端:封装套接字创建、连接、发送、监听与关闭。
``listen()`` 在调用线程内阻塞运行,可另开线程调用 ``stop()`` 来终止。
Usage::
def on_msg(text: str) -> None:
print(f"收到: {text}")
c = MsgClient("localhost", 8003, "Alice")
c.connect()
c.send("hello") # 发送单条消息
c.listen(on_msg) # 阻塞当前线程,持续回调
"""
def __init__(self, addr: str, port: int, name: str) -> None:
self.addr = addr
self.port = port
self.name = name
self._sock: "_socket.socket | None" = None
self._running = False
# ---- 连接 ------------------------------------------------------------
def connect(self) -> None:
"""创建 TCP 套接字并连接到服务器。"""
self._sock = _socket.socket(_socket.AF_INET, _socket.SOCK_STREAM)
self._sock.connect((self.addr, self.port))
# ---- 发送单条消息(短连接)--------------------------------------------
def send(self, msg: str) -> None:
"""发送一条消息到服务器(使用短连接,pymsg 协议)。"""
try:
with _socket.socket(_socket.AF_INET, _socket.SOCK_STREAM) as s:
s.settimeout(3)
s.connect((self.addr, self.port))
send(s, f"{self.name}: {msg}")
except ConnectionRefusedError:
raise ConnectionRefusedError(
f"Could not connect to {self.addr}:{self.port}"
)
# ---- 持续监听(阻塞当前线程,回调模式)-------------------------------
def listen(self, on_message: "callable") -> None:
"""阻塞当前线程,持续接收服务器消息并回调。
Args:
on_message: 回调 ``on_message(text: str) -> None``。
"""
if self._sock is None:
raise RuntimeError("必须先调用 connect()")
self._running = True
socklist = [self._sock]
while self._running:
try:
readable, _, exception = select.select(
socklist, [], socklist, 0.1
)
if readable:
try:
text = recv(self._sock)
on_message(text)
except ConnectionError:
break
if exception:
break
except (ConnectionResetError, OSError):
break
# ---- 关闭 ------------------------------------------------------------
def stop(self) -> None:
"""设置停止标志并断开 TCP 连接。
可在另一个线程中调用,使 ``listen()`` 退出阻塞。
"""
self._running = False
if self._sock is not None:
try:
self._sock.close()
except OSError:
pass
self._sock = None
class MsgServer:
"""基于 pymsg 长度前缀协议的多客户端 TCP 服务器。
收到消息时调用回调函数 —— 转发、过滤等逻辑全部在回调中实现。
Usage::
def on_msg(sender_sock, addr, text):
# 转发给所有人(排除发送者)
server.broadcast(f"[{addr}] {text}", except_sock=sender_sock)
server = MsgServer("0.0.0.0", 8003)
server.start(on_msg) # 阻塞当前线程
# 在另一线程中调用 server.stop() 可优雅退出
"""
def __init__(self, addr: str, port: int) -> None:
self.addr = addr
self.port = port
self._running = False
self._server_sock: "_socket.socket | None" = None
self._clients: "dict" = {} # socket -> (ip, port)
# ---- 启动(阻塞)----------------------------------------------------
def start(self, on_message: "callable") -> None:
"""启动服务器,阻塞当前线程。
Args:
on_message: 回调 ``on_message(sock, addr, text)``
- sock: 发送消息的客户端套接字
- addr: (ip, port) 元组
- text: 解码后的字符串消息
"""
self._running = True
servsock = _socket.socket(_socket.AF_INET, _socket.SOCK_STREAM)
servsock.setsockopt(_socket.SOL_SOCKET, _socket.SO_REUSEADDR, 1)
servsock.bind((self.addr, self.port))
servsock.listen(10)
self._server_sock = servsock
socketlist = [servsock]
while self._running:
try:
readable, _, exception = select.select(
socketlist, [], socketlist, 0.1
)
except (ValueError, OSError):
break
for s in exception:
self._remove_client(s, socketlist)
for s in readable:
if s is servsock:
self._accept_client(servsock, socketlist)
else:
self._handle_client(s, socketlist, on_message)
self._shutdown(servsock, socketlist)
# ---- 广播 -----------------------------------------------------------
def broadcast(
self, msg: str, except_sock: "_socket.socket | None" = None
) -> None:
"""向所有已连接客户端广播消息(pymsg 协议)。
Args:
msg: 要发送的字符串。
except_sock: 排除的套接字(通常为发送者),不向其发送。
"""
disconnected = []
for client in list(self._clients):
if client is except_sock:
continue
try:
send(client, msg)
except (BrokenPipeError, ConnectionResetError, OSError):
disconnected.append(client)
for client in disconnected:
self._clients.pop(client, None)
try:
client.close()
except OSError:
pass
# ---- 应答 -----------------------------------------------------------
def reply(self, sock: "_socket.socket", msg: str) -> None:
"""向指定客户端套接字发送一条应答消息(pymsg 协议)。
用于请求-应答模式:服务器收到消息后,通过同一 socket 回复处理结果。
"""
send(sock, msg)
# ---- 停止 -----------------------------------------------------------
def stop(self) -> None:
"""设置停止标志并关闭监听套接字(可从另一线程调用)。"""
self._running = False
if self._server_sock is not None:
try:
self._server_sock.close()
except OSError:
pass
# ---- 内部方法 -------------------------------------------------------
def _accept_client(self, servsock, socketlist):
try:
client_sock, client_addr = servsock.accept()
if client_sock.fileno() != -1:
socketlist.append(client_sock)
self._clients[client_sock] = client_addr
except OSError:
pass
def _handle_client(self, s, socketlist, on_message):
try:
text = recv(s)
on_message(s, self._clients.get(s, ("unknown", 0)), text)
except (ConnectionError, ConnectionResetError, OSError):
self._remove_client(s, socketlist)
def _remove_client(self, s, socketlist):
self._clients.pop(s, None)
if s in socketlist:
socketlist.remove(s)
try:
s.close()
except OSError:
pass
def _shutdown(self, servsock, socketlist):
for s in socketlist:
try:
s.close()
except OSError:
pass
self._clients.clear()