Django3基于ASGI与WebSocket实现WebShell的详细过程
发布时间：2026-10-15| 3人浏览过
本文详细介绍如何在Django3环境中利用原生ASGI协议实现WebSocket服务，进而构建WebShell。通过结合Gunicorn、Uvicorn、Paramiko以及前端xterm.js，实现了从React前端到远程虚拟机的字符交互与命令回显，提供了完整的实现思路与核心代码参考。
前言
近期工作需求涉及开发前端操作远程虚拟机的功能，即WebShell。基于现有的React与Django技术栈进行调研，发现多数后端方案采用Django配合Channels来提供WebSocket服务。考虑到这种方案缺乏探索性，查阅Django官方文档后得知，Django原生并不直接支持WebSocket，但从Django3版本开始支持ASGI协议，允许开发者自行实现WebSocket服务。因此，最终确定的技术组合为：Gunicorn + Uvicorn + ASGI + WebSocket + Django3.2 + Paramiko。
实现websocket服务
使用Django脚手架生成的项目中会自动包含asgi.py和wsgi.py两个文件。常规应用通常使用wsgi.py配合Nginx进行线上部署，而本次主要使用asgi.py。实现WebSocket服务的思路在网络上较为常见，核心在于处理connect、send、receive和disconnect这几个动作。参考“How to Add Websockets to a Django App without Extra Dependencies”一文是一个不错的实例，但其实现过于简单，不足以应对复杂场景。
思路
# asgi.py
import os
from django.core.asgi import get_asgi_application
from websocket_app.websocket import websocket_application
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'websocket_app.settings')
django_application = get_asgi_application()
async def application(scope, receive, send):
if scope['type'] == 'http':
await django_application(scope, receive, send)
elif scope['type'] == 'websocket':
await websocket_application(scope, receive, send)
else:
raise NotImplementedError(f"Unknown scope type {scope['type']}")
# websocket.py
async def websocket_application(scope, receive, send):
pass
# websocket.py
async def websocket_application(scope, receive, send):
while True:
event = await receive()
if event['type'] == 'websocket.connect':
await send({
'type': 'websocket.accept'
})
if event['type'] == 'websocket.disconnect':
break
if event['type'] == 'websocket.receive':
if event['text'] == 'ping':
await send({
'type': 'websocket.send',
'text': 'pong!'
})实现
上述代码提供了基本思路，较为完整的参考可参见“websockets-in-django-3-1”，基本可以直接复用。其中最核心的实现部分如下所示：
class WebSocket:
def __init__(self, scope, receive, send):
self._scope = scope
self._receive = receive
self._send = send
self._client_state = State.CONNECTING
self._app_state = State.CONNECTING
@property
def headers(self):
return Headers(self._scope)
@property
def scheme(self):
return self._scope["scheme"]
@property
def path(self):
return self._scope["path"]
@property
def query_params(self):
return QueryParams(self._scope["query_string"].decode())
@property
def query_string(self) -> str:
return self._scope["query_string"]
@property
def scope(self):
return self._scope
async def accept(self, subprotocol: str = None):
"""Accept connection.
:param subprotocol: The subprotocol the server wishes to accept.
:type subprotocol: str, optional
"""
if self._client_state == State.CONNECTING:
await self.receive()
await self.send({"type": SendEvent.ACCEPT, "subprotocol": subprotocol})
async def close(self, code: int = 1000):
await self.send({"type": SendEvent.CLOSE, "code": code})
async def send(self, message: t.Mapping):
if self._app_state == State.DISCONNECTED:
raise RuntimeError("WebSocket is disconnected.")
if self._app_state == State.CONNECTING:
assert message["type"] in {SendEvent.ACCEPT, SendEvent.CLOSE}, (
'Could not write event "%s" into socket in connecting state.'
% message["type"]
)
if message["type"] == SendEvent.CLOSE:
self._app_state = State.DISCONNECTED
else:
self._app_state = State.CONNECTED
elif self._app_state == State.CONNECTED:
assert message["type"] in {SendEvent.SEND, SendEvent.CLOSE}, (
'Connected socket can send "%s" and "%s" events, not "%s"'
% (SendEvent.SEND, SendEvent.CLOSE, message["type"])
)
if message["type"] == SendEvent.CLOSE:
self._app_state = State.DISCONNECTED
await self._send(message)
async def receive(self):
if self._client_state == State.DISCONNECTED:
raise RuntimeError("WebSocket is disconnected.")
message = await self._receive()
if self._client_state == State.CONNECTING:
assert message["type"] == ReceiveEvent.CONNECT, (
'WebSocket is in connecting state but received "%s" event'
% message["type"]
)
self._client_state = State.CONNECTED
elif self._client_state == State.CONNECTED:
assert message["type"] in {ReceiveEvent.RECEIVE, ReceiveEvent.DISCONNECT}, (
'WebSocket is connected but received invalid event "%s".'
% message["type"]
)
if message["type"] == ReceiveEvent.DISCONNECT:
self._client_state = State.DISCONNECTED
return message缝合怪
作为高效的代码整合者，为了提高效率并填平坑洼，需要将上述WebSocket类与Paramiko库结合，从而实现从前段接收字符并传递给远程主机，同时接收返回数据的功能。
import asyncio
import traceback
import paramiko
from webshell.ssh import Base, RemoteSSH
from webshell.connection import WebSocket
class WebShell:
"""整理 WebSocket 和 paramiko.Channel,实现两者的数据互通"""
def __init__(self, ws_session: WebSocket,
ssh_session: paramiko.SSHClient = None,
chanel_session: paramiko.Channel = None
):
self.ws_session = ws_session
self.ssh_session = ssh_session
self.chanel_session = chanel_session
def init_ssh(self, host=None, port=22, user="admin", passwd="admin@123"):
self.ssh_session, self.chanel_session = RemoteSSH(host, port, user, passwd).session()
def set_ssh(self, ssh_session, chanel_session):
self.ssh_session = ssh_session
self.chanel_session = chanel_session
async def ready(self):
await self.ws_session.accept()
async def welcome(self):
# 展示Linux欢迎相关内容
for i in range(2):
if self.chanel_session.send_ready():
message = self.chanel_session.recv(2048).decode('utf-8')
if not message:
return
await self.ws_session.send_text(message)
async def web_to_ssh(self):
# print('--------web_to_ssh------->')
while True:
# print('--------------->')
if not self.chanel_session.active or not self.ws_session.status:
return
await asyncio.sleep(0.01)
shell = await self.ws_session.receive_text()
# print('-------shell-------->', shell)
if self.chanel_session.active and self.chanel_session.send_ready():
self.chanel_session.send(bytes(shell, 'utf-8'))
# print('--------------->', "end")
async def ssh_to_web(self):
# print('<--------ssh_to_web-----------')
while True:
# print('<-------------------')
if not self.chanel_session.active:
await self.ws_session.send_text('ssh closed')
return
if not self.ws_session.status:
return
await asyncio.sleep(0.01)
if self.chanel_session.recv_ready():
message = self.chanel_session.recv(2048).decode('utf-8')
# print('<---------message----------', message)
if not len(message):
continue
await self.ws_session.send_text(message)
# print('<-------------------', "end")
async def run(self):
if not self.ssh_session:
raise Exception("ssh not init!")
await self.ready()
await asyncio.gather(
self.web_to_ssh(),
self.ssh_to_web()
)
def clear(self):
try:
self.ws_session.close()
except Exception:
traceback.print_stack()
try:
self.ssh_session.close()
except Exception:
traceback.print_stack()
前端
前端终端模拟可使用xterm.js，搜索并选择一个界面简洁的库即可满足需求。
export class Term extends React.Component {
private terminal!: HTMLDivElement;
private fitAddon = new FitAddon();
componentDidMount() {
const xterm = new Terminal();
xterm.loadAddon(this.fitAddon);
xterm.loadAddon(new WebLinksAddon());
// using wss for https
// const socket = new WebSocket("ws://" + window.location.host + "/api/v1/ws");
const socket = new WebSocket("ws://localhost:8000/webshell/");
// socket.onclose = (event) => {
// this.props.onClose();
// }
socket.onopen = (event) => {
xterm.loadAddon(new AttachAddon(socket));
this.fitAddon.fit();
xterm.focus();
}
xterm.open(this.terminal);
xterm.onResize(({ cols, rows }) => {
socket.send("<RESIZE>" + cols + "," + rows)
});
window.addEventListener('resize', this.onResize);
}
componentWillUnmount() {
window.removeEventListener('resize', this.onResize);
}
onResize = () => {
this.fitAddon.fit();
}
render() {
return <div className="Terminal" ref={(ref) => this.terminal = ref as HTMLDivElement}></div>;
}
}不再赘述，完整代码已托管于“webshell”仓库，欢迎Star或Fork！
参考资料
webshell
django文档
graphene-django文档
django 异步视图
websockets-in-django-3-1
How to Add Websockets to a Django App without Extra Dependencies
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