code_validator.py

import subprocess
import tempfile
import os
import shutil


class CodeValidator:
    def __init__(self):
        self.timeout = 2
        self.python_exec = shutil.which("python") or shutil.which("python3")
        self.node_available = shutil.which("node") is not None

    def validate(self, language, code):

        if not code:
            return self._fail("empty code")

        if language == "python":
            return self._run_python(code)

        if language == "javascript":
            return self._run_node(code)

        return self._fail("unsupported")

    def _run_python(self, code):
        path = None

        try:
            path = self._write(code, ".py")

            r = subprocess.run(
                [self.python_exec, path],
                capture_output=True,
                text=True,
                timeout=self.timeout
            )

            return self._format(r)

        except Exception as e:
            return self._fail(str(e))

        finally:
            self._clean(path)

    def _run_node(self, code):
        if not self.node_available:
            return self._fail("node missing")

        path = None

        try:
            path = self._write(code, ".js")

            r = subprocess.run(
                ["node", path],
                capture_output=True,
                text=True,
                timeout=self.timeout
            )

            return self._format(r)

        except Exception as e:
            return self._fail(str(e))

        finally:
            self._clean(path)

    def _write(self, code, ext):
        f = tempfile.NamedTemporaryFile("w", suffix=ext, delete=False)
        f.write(code)
        f.close()
        return f.name

    def _clean(self, path):
        if path and os.path.exists(path):
            try:
                os.remove(path)
            except:
                pass

    def _format(self, r):
        return {
            "success": r.returncode == 0,
            "stdout": r.stdout,
            "stderr": r.stderr,
            "returncode": r.returncode
        }

    def _fail(self, msg):
        return {"success": False, "stderr": msg, "returncode": -1}