使用 jsr:@langchain/pyodide-sandbox 构建 Python 安全沙箱

den run -A jsr:@langchain/pyodide-sandbox \ -c "print('Hello, World')"

输出：

{"stdout":"Hello, World","stderr":null,"result":null,"success":true,"sessionMetadata":{"created":"2026-01-22T02:13:43.619Z","lastModified":"2026-01-22T02:13:43.660Z","packages":[]}} 

4.2 执行计算

den run -A jsr:@langchain/pyodide-sandbox \ -c "print(2 + 3)"

{"stdout":"5","stderr":null,"result":null,"success":true,"sessionMetadata":{"created":"2026-01-22T02:09:58.743Z","lastModified":"2026-01-22T02:09:58.794Z","packages":[]}} 

五、自动安装 Python 包（micropip）

Pyodide 无需 pip / venv，而是使用 micropip。

5.1 使用 numpy 示例

den run -A jsr:@langchain/pyodide-sandbox \ -c "import numpy as np; print(np.arange(5))"

首次执行会看到：

{"stdout":"Loading numpyDidn't find package numpy-2.0.2-cp312-cp312-pyodide_2024_0_wasm32.whl locally, attempting to load from https://cdn.jsdelivr.net/pyodide/v0.27.7/full/Package numpy-2.0.2-cp312-cp312-pyodide_2024_0_wasm32.whl loaded from https://cdn.jsdelivr.net/pyodide/v0.27.7/full/, caching the wheel in node_modules for future use.Loaded numpy[0 1 2 3 4]","stderr":null,"result":null,"success":true,"sessionMetadata":{"created":"2026-01-22T02:14:13.300Z","lastModified":"2026-01-22T02:14:17.036Z","packages":["numpy"]}} 

这是 正常行为，表示：

• Pyodide 正在下载依赖
• 下载完成后会缓存到 node_modules
• 后续执行不会再下载

六、Stateful 会话（保持执行状态）

默认情况下，每次执行是 无状态的。

如果你希望多次执行共享变量，需要开启 stateful 模式。

6.1 创建 state

den run -A jsr:@langchain/pyodide-sandbox \ -s -c "x = 42"

会返回 sessionBytes。

{"stdout":null,"stderr":null,"result":null,"success":true,"sessionBytes":[128,4,149,168,0,0,0,0,0,0,0,140,10,100,105,108,108,46,95,100,105,108,108,148,140,14,95,105,109,112,111,114,116,95,109,111,100,117,108,101,148,147,148,140,8,95,95,109,97,105,110,95,95,148,133,148,82,148,125,148,40,140,8,95,95,110,97,109,101,95,95,148,104,3,140,7,95,95,100,111,99,95,95,148,78,140,11,95,95,112,97,99,107,97,103,101,95,95,148,78,140,8,95,95,115,112,101,99,95,95,148,78,140,15,95,95,97,110,110,111,116,97,116,105,111,110,115,95,95,148,125,148,140,13,95,112,121,111,100,105,100,101,95,99,111,114,101,148,104,2,140,13,95,112,121,111,100,105,100,101,95,99,111,114,101,148,133,148,82,148,140,1,120,148,75,42,117,98,46],"sessionMetadata":{"created":"2026-01-22T02:14:55.543Z","lastModified":"2026-01-22T02:14:56.955Z","packages":["dill"]}}

6.2 恢复 state

jsr:@langchain/pyodide-sandbox 的 stateful 会话由 两部分组成：

CLI 在恢复 session 时需要：

sessionBytes → 还原 Python 对象 sessionMetadata → 校验 & 环境一致性 

den run -A jsr:@langchain/pyodide-sandbox \ -s \ -b '<sessionBytes>'\ -m '<sessionMetadata>'\ -c "print(x)"

例子

den run -A jsr:@langchain/pyodide-sandbox \ -s \ -b '[128,4,149,168,0,0,0,0,0,0,0,140,10,100,105,108,108,46,95,100,105,108,108,148,140,14,95,105,109,112,111,114,116,95,109,111,100,117,108,101,148,147,148,140,8,95,95,109,97,105,110,95,95,148,133,148,82,148,125,148,40,140,8,95,95,110,97,109,101,95,95,148,104,3,140,7,95,95,100,111,99,95,95,148,78,140,11,95,95,112,97,99,107,97,103,101,95,95,148,78,140,8,95,95,115,112,101,99,95,95,148,78,140,15,95,95,97,110,110,111,116,97,116,105,111,110,115,95,95,148,125,148,140,13,95,112,121,111,100,105,100,101,95,99,111,114,101,148,104,2,140,13,95,112,121,111,100,105,100,101,95,99,111,114,101,148,133,148,82,148,140,1,120,148,75,42,117,98,46]'\ -m '{"created":"2026-01-22T02:14:55.543Z","lastModified":"2026-01-22T02:14:56.955Z","packages":["dill"]}'\ -c "print(x)"

输出：

{"stdout":"42","stderr":null,"result":null,"success":true,"sessionBytes":[128,4,149,168,0,0,0,0,0,0,0,140,10,100,105,108,108,46,95,100,105,108,108,148,140,14,95,105,109,112,111,114,116,95,109,111,100,117,108,101,148,147,148,140,8,95,95,109,97,105,110,95,95,148,133,148,82,148,125,148,40,140,8,95,95,110,97,109,101,95,95,148,104,3,140,7,95,95,100,111,99,95,95,148,78,140,11,95,95,112,97,99,107,97,103,101,95,95,148,78,140,8,95,95,115,112,101,99,95,95,148,78,140,15,95,95,97,110,110,111,116,97,116,105,111,110,115,95,95,148,125,148,140,13,95,112,121,111,100,105,100,101,95,99,111,114,101,148,104,2,140,13,95,112,121,111,100,105,100,101,95,99,111,114,101,148,133,148,82,148,140,1,120,148,75,42,117,98,46],"sessionMetadata":{"created":"2026-01-22T02:14:55.543Z","lastModified":"2026-01-22T02:18:31.879Z","packages":["dill"]}} 

七、Python 正确执行模板（非常重要）

⚠️ 很多人踩坑就在这里

❌ 错误写法

2+3

或者：

print(2+3)

这样不会返回 result，只会进 stdout。

✅ 正确写法（标准模板）

async def main(args):
    return 2 + 3

✅ 同时 print + return

async def main(args):
    print("hello")
    return {"sum": 2 + 3}

返回结构：

{"stdout":"hello\n","result":{"sum":5}}

八、在 Python 中集成（推荐）

LangChain 官方提供了 Python 封装包：

8.1 安装

pip install langchain-sandbox 

8.2 Python 示例

from langchain_sandbox import PyodideSandbox
import asyncio

async def run():
    sandbox = PyodideSandbox(
        allow_net=False,
        allow_read=False,
        allow_write=False,
    )
    result = await sandbox.execute("""
    async def main(args):
        print("hello from pyodide")
        return 1 + 2
    await main({})
    """)
    print("status:", result.status)
    print("stdout:", result.stdout)
    print("result:", result.result)

asyncio.run(run())

结果

status: success
stdout: hello from pyodide
result: 3

九、权限控制（安全关键）

示例：

sandbox = PyodideSandbox(
    allow_net=False,
    allow_read=["data"],
    allow_write=False,
    memory_limit_mb=32,
)

十、典型应用场景

✔ LLM Agent 执行代码
✔ LangChain Tool Sandbox
✔ 在线 Python 解释器
✔ 插件系统
✔ 教育 / 判题系统

十一、常见问题

Q1：stdout 很乱正常吗？

✅ 正常
第一次会输出 Pyodide 包安装日志
生产环境请只信 result 字段

Q2：能安装 pandas / numpy 吗？

⚠️ 只能安装 pure Python / WASM 兼容包
❌ 不支持 CPython C 扩展（如 torch）

十二、官方资源汇总

• JSR 文档
  https://jsr.io/@langchain/pyodide-sandbox
• GitHub 源码
  https://github.com/langchain-ai/langchain-sandbox
• Pyodide 官方文档
  https://pyodide.org
• Python 封装
  https://pypi.org/project/langchain-sandbox

十三、总结

jsr:@langchain/pyodide-sandbox 是目前 LLM 场景下最优雅的 Python 沙箱方案之一：

轻量、安全、Agent 友好

非常适合用在：

• AI Agent
• 多租户执行
• 自动化平台