app.py

import gradio as gr
import subprocess
from typing import Tuple
import os

# Security: Define allowed commands or use a whitelist approach
DANGEROUS_COMMANDS = ['rm -rf /', 'dd if=', 'mkfs', ':(){ :|:& };:']

async def run_command(command: str) -> Tuple[str, str]:
    """
    Run a command on shell with improved security and error handling.
    
    Args:
        command: Shell command to execute
        
    Returns:
        Tuple of (output, status_message)
    """
    if not command or not command.strip():
        return "", "❌ Error: Empty command provided"
    
    # Basic security check for obviously dangerous commands
    for dangerous in DANGEROUS_COMMANDS:
        if dangerous in command:
            return "", f"🚫 Security: Command blocked (contains: {dangerous})"
    
    try:
        # Use subprocess instead of os.popen for better control
        result = subprocess.run(
            command,
            shell=True,
            capture_output=True,
            text=True,
            timeout=30,  # Prevent hanging commands
            cwd=os.getcwd()
        )
        
        # Combine stdout and stderr
        output = result.stdout
        if result.stderr:
            output += f"\n--- STDERR ---\n{result.stderr}"
        
        if result.returncode == 0:
            status = f"✅ Success (exit code: {result.returncode})"
        else:
            status = f"⚠️ Command exited with code: {result.returncode}"
            
        return output or "(no output)", status
        
    except subprocess.TimeoutExpired:
        return "", "⏱️ Error: Command timed out (30s limit)"
    except Exception as e:
        return "", f"❌ Error: {str(e)}"


def create_interface():
    """Create the Gradio interface with improved UI"""
    with gr.Blocks(
        title="Shell Command Executor",
    ) as demo:
        gr.Markdown("""
        # 🖥️ Shell Command Executor
        Execute shell commands safely with timeout protection and error handling.
        
        **⚠️ Warning**: Use with caution. Some dangerous commands are blocked.
        """)
        
        with gr.Row():
            with gr.Column(scale=2):
                command_input = gr.Textbox(
                    label="Command",
                    placeholder="Enter your shell command (e.g., ls -la, pwd, echo 'hello')",
                    lines=2
                )
                
                with gr.Row():
                    run_btn = gr.Button("▶️ Run Command", variant="primary")
                    clear_btn = gr.Button("🗑️ Clear")
            
            with gr.Column(scale=1):
                status_output = gr.Textbox(
                    label="Status",
                    lines=2,
                    interactive=False
                )
        
        output_display = gr.Code(
            label="Output",
            language="shell",
            lines=15
        )
        
        gr.Markdown("""
        ### 📝 Example Commands
        - `pwd` - Print working directory
        - `ls -la` - List files with details
        - `whoami` - Show current user
        - `df -h` - Show disk usage
        - `ps aux | head -n 10` - Show top 10 processes
        """)
        
        # Event handlers
        run_btn.click(
            fn=run_command,
            inputs=command_input,
            outputs=[output_display, status_output]
        )
        
        command_input.submit(
            fn=run_command,
            inputs=command_input,
            outputs=[output_display, status_output]
        )
        
        clear_btn.click(
            fn=lambda: ("", "", ""),
            outputs=[command_input, output_display, status_output]
        )
    
    return demo


if __name__ == "__main__":
    print("🚀 Starting Shell Command Executor...")
    print("⚠️  Security features enabled: timeout protection, basic command filtering")
    
    demo = create_interface()
    demo.launch(
        mcp_server=True,
        show_error=True)