createProxy.js

const http = require('http');
const https = require('https');
const { URL } = require('url');

function createProxy(targetBase) {
  const targetBaseUrl = new URL(targetBase);

  return async function (req, res, next) {
    try {
      // Reconstitue l'URL finale avec le path et les query params
      const targetPath = req.originalUrl.replace(req.baseUrl, '') || '/';
      const query = req.url.includes('?') ? req.url.split('?')[1] : '';
      const targetUrl = new URL(targetPath, targetBaseUrl);
      if (query) targetUrl.search = '?' + query;

      // Choisir le bon module HTTP
      const client = targetUrl.protocol === 'https:' ? https : http;

      // Lire le corps de la requête s'il y en a un
      const chunks = [];
      req.on('data', chunk => chunks.push(chunk));
      req.on('end', () => {
        const body = Buffer.concat(chunks);

        // Préparer les options de la requête sortante
        const options = {
          method: req.method,
          headers: {
            ...req.headers,
            host: targetUrl.host, // remplace l'en-tête Host
          },
        };

        const proxyReq = client.request(targetUrl, options, proxyRes => {
          res.writeHead(proxyRes.statusCode, proxyRes.headers);
          proxyRes.pipe(res);
        });

        proxyReq.on('error', err => {
          console.error('Proxy error:', err);
          res.statusCode = 502;
          res.end('Proxy Error');
        });

        // Transmet le corps s’il existe
        if (body.length) {
          proxyReq.write(body);
        }

        proxyReq.end();
      });
    } catch (err) {
      console.error('Internal proxy error:', err);
      res.statusCode = 500;
      res.end('Internal Server Error');
    }
  };
}

module.exports = createProxy;
/*
Exemple usage:
const express = require('express');
const bodyParser = require('body-parser');
const createProxy = require('./createProxy');

const app = express();

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

// Exemple : proxifier /github → https://github.com
app.use('/github', createProxy('https://github.com'));
app.use('/httpbin', createProxy('https://httpbin.org'));

app.listen(3000, () => {
  console.log('Proxy server listening on http://localhost:3000');
});
*/