sathish2352/compiler

1# app.py2# This is the main file for our FastAPI application.3 4import io5import sys6from fastapi import FastAPI, HTTPException7from pydantic import BaseModel8from fastapi.middleware.cors import CORSMiddleware9 10# Initialize the FastAPI app11app = FastAPI(12    title="Python Code Executor API",13    description="An API to execute Python code securely and return the output.",14    version="1.0.0",15)16 17# --- CORS Middleware ---18# This is important to allow your front-end website (running on a different domain)19# to communicate with this API. We'll allow all origins for simplicity.20app.add_middleware(21    CORSMiddleware,22    allow_origins=["*"],  # Allows all origins23    allow_credentials=True,24    allow_methods=["*"],  # Allows all methods (GET, POST, etc.)25    allow_headers=["*"],  # Allows all headers26)27 28 29# --- Request Body Model ---30# This Pydantic model defines the structure of the JSON we expect in the request.31# It ensures that the incoming data has a "code" field which is a string.32class Code(BaseModel):33    code: str34 35 36# --- API Endpoint ---37# This defines the endpoint at the path "/execute" that accepts POST requests.38@app.post("/execute")39async def execute_python_code(code_payload: Code):40    """41    Executes the provided Python code and returns its output or any errors.42    """43    # Create a string buffer to capture the output of the print() statements44    old_stdout = sys.stdout45    redirected_output = io.StringIO()46    sys.stdout = redirected_output47 48    try:49        # The exec() function executes the Python code passed as a string.50        # We pass an empty dictionary for globals and locals for a cleaner scope.51        exec(code_payload.code, {}, {})52    except Exception as e:53        # If any error occurs during execution, restore stdout and raise an HTTPException.54        # This will be sent back to the user as a proper error response.55        sys.stdout = old_stdout56        raise HTTPException(57            status_code=400,58            detail=f"Error executing code: {str(e)}"59        )60    finally:61        # This 'finally' block ensures that we always restore the original stdout,62        # even if an error occurred. This is crucial for the server's stability.63        sys.stdout = old_stdout64 65    # Get the captured output from the string buffer66    output = redirected_output.getvalue()67 68    # Return the captured output in a JSON response69    return {"output": output}70 71# A simple root endpoint to confirm the API is running72@app.get("/")73def read_root():74    return {"message": "Python Code Executor API is running."}75