index.js

const express = require("express");
const app = express();
const bodyParser = require("body-parser");
const cors = require("cors");
const fs = require("fs");
const { exec } = require("child_process");
const compiler = require("compilex");
const options = { stats: true };
compiler.init(options);

app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(cors());

app.get("/", function (req, res) {
  res.send("Hello World!!");
});

app.post("/compile", function (req, res) {
    var code = req.body.code;
    var input = req.body.input;
    var lang = req.body.lang;
  
    try {
       if (lang == "Python") {
        if (!input) {
          var envData = { OS: "linux" };
          compiler.compilePython(envData, code, function (data) {
            if (data.output) {
              res.send(data);
            } else {
              res.send({ error: data.error });
            }
          });
        } else {
          var envData = { OS: "linux" };
          compiler.compilePythonWithInput(envData, code, input, function (data) {
            if (data.output) {
              res.send(data);
            } else {
              res.send({ error: data.error });
            }
          });
        }
      } else if (lang == "Java") {
        fs.writeFile("/code/temp/Main.java", code, (err) => {
          if (err) {
            console.error(err);
            res.status(500).send("Error writing Java file");
            return;
          }
          const javaProcess = exec(
            "javac -d /code/temp /code/temp/Main.java && java -cp /code/temp Main",
            (error, stdout, stderr) => {
              if (error) {
                console.error(error);
                res.send({ error: stderr });
                return;
              }
              console.log(stdout);
              console.error(stderr);
              res.send({ output: stdout });
            }
          );
          if (input) {
            javaProcess.stdin.write(input);
            javaProcess.stdin.end();
          }

          // Timeout functionality
          const timeout = 5000; // 5 seconds timeout
          let isTimeout = false;
          const timeoutId = setTimeout(() => {
            isTimeout = true;
            javaProcess.kill(); // Kill the process if it exceeds the timeout
            res.status(408).send({ error: "Time Limit Exceeded" });
          }, timeout);

          javaProcess.on("exit", () => {
            clearTimeout(timeoutId); // Clear the timeout if the process exits before the timeout
            if (!isTimeout) {
              res.send({ output: stdout });
            }
          });
        });
      } else if (lang == "Cpp") {
        fs.writeFile("/code/temp/Main.cpp", code, (err) => {
          if (err) {
            console.error(err);
            res.status(500).send("Error writing C++ file");
            return;
          }
          const cppProcess = exec(
            "g++ -o /code/temp/Main /code/temp/Main.cpp && /code/temp/Main",
            (error, stdout, stderr) => {
              if (error) {
                console.error(error);
                res.send({ error: stderr });
                return;
              }
              console.log(stdout);
              console.error(stderr);
              res.send({ output: stdout });
            }
          );
          if (input) {
            cppProcess.stdin.write(input);
            cppProcess.stdin.end();
          }

          // Timeout functionality
          const timeout = 5000; // 5 seconds timeout
          let isTimeout = false;
          const timeoutId = setTimeout(() => {
            isTimeout = true;
            cppProcess.kill(); // Kill the process if it exceeds the timeout
            res.status(408).send({ error: "Time Limit Exceeded" });
          }, timeout);

          cppProcess.on("exit", () => {
            clearTimeout(timeoutId); // Clear the timeout if the process exits before the timeout
            if (!isTimeout) {
              res.send({ output: stdout });
            }
          });
        });
      }
    } catch (e) {
      console.log("error:" + e);
    }
});

const port = 7860;
app.listen(port, () => {
  console.log(`Open http://localhost:${port}`);
});