Django3 使用 WebSocket 实现 WebShell
2021-09-30
前言
最近工作中需要开发前端操作远程虚拟机的功能,简称 WebShell。基于当前的技术栈为 react+django,调研了一会发现大部分的后端实现都是 django+channels 来实现 websocket 服务。
大致看了下觉得这不够有趣,翻了翻 django 的官方文档发现 django 原生是不支持 websocket 的,但 django3 之后支持了 asgi 协议可以自己实现 websocket 服务。
于是选定 gunicorn+uvicorn+asgi+websocket+django3.2+paramiko 来实现 WebShell。
实现 websocket 服务
使用 django 自带的脚手架生成的项目会自动生成 asgi.py 和 wsgi.py 两个文件,普通应用大部分用的都是 wsgi.py 配合 nginx 部署线上服务。
这次主要使用 asgi.py 实现 websocket 服务的思路大致网上搜一下就能找到,主要就是实现 connect/send/receive/disconnect 这个几个动作的处理方法。
这里 How to Add Websockets to a Django App without Extra Dependencies就是一个很好的实例,但过于简单……
思路
# asgi.py import os
from django.core.asgi import get_asgi_applicationfrom 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.pyasync def websocket_application(scope, receive, send): pass
# websocket.pyasync 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
上面的代码提供了思路
其中最核心的实现部分我放下面:
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
做为合格的代码搬运工,为了提高搬运效率还是要造点轮子填点坑的,如何将上面的 WebSocket 类与 paramiko 结合起来,实现从前端接受字符传递给远程主机,并同时接受返回呢?
import asyncioimport tracebackimport paramikofrom webshell.ssh import Base, RemoteSSHfrom 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
xterm.js 完全满足,搜索下找个看着简单的就行。
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>; }}
原文链接:https://www.cnblogs.com/lgjbky/p/15186188.html
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