server.js

const express = require('express');
const proxy = require('express-http-proxy');
const bodyParser = require('body-parser');

const app = express();
const targetUrl = 'https://api.openai.com';
const openai_key = process.env.OPENAI_KEY;

app.use(bodyParser.json()); // Middleware to parse JSON body

// Route to handle GPT-4 generation requests
app.post('/generate', proxy(targetUrl, {
  proxyReqPathResolver: () => '/v1/engines/gpt-4-1106-preview/completions', // Path for GPT-4 requests
  proxyReqOptDecorator: (proxyReqOpts, srcReq) => {
    // Ensure the model is GPT-4
    if (srcReq.body.model !== 'gpt-4-1106-preview') {
      throw new Error('Only gpt-4-1106-preview model is supported');
    }

    // Modify the request headers
    proxyReqOpts.headers['Authorization'] = `Bearer ${openai_key}`;
    proxyReqOpts.headers['Content-Type'] = 'application/json';

    // Forward the JSON body as-is
    proxyReqOpts.bodyContent = JSON.stringify(srcReq.body);

    return proxyReqOpts;
  },
  userResDecorator: (proxyRes, proxyResData, userReq, userRes) => {
    // Check for non-200 status code
    if (proxyRes.statusCode !== 200) {
      throw new Error('Request to OpenAI failed');
    }
    // Forward the OpenAI response
    return proxyResData;
  },
}));

// All other requests are not allowed
app.use('*', (req, res) => {
  res.status(403).send('Access Denied');
});

const port = 7860;
app.listen(port, () => {
  console.log(`Reverse proxy server listening on port ${port}`);
});