feat: make vercel compatible

Signed-off-by: Tony Tang <tonytang@lilith.com>

api/index.js

@@ -0,0 +1,61 @@
+const cors_proxy = require('../lib/cors-anywhere');
+
+// Parse environment variables for configuration
+function parseEnvList(env) {
+  if (!env) {
+    return [];
+  }
+  return env.split(',');
+}
+
+const originBlacklist = parseEnvList(process.env.CORSANYWHERE_BLACKLIST);
+const originWhitelist = parseEnvList(process.env.CORSANYWHERE_WHITELIST);
+
+// Set up rate-limiting to avoid abuse
+const checkRateLimit = require('../lib/rate-limit')(process.env.CORSANYWHERE_RATELIMIT);
+
+// Create the CORS Anywhere server options
+const options = {
+  originBlacklist: originBlacklist,
+  originWhitelist: originWhitelist,
+  requireHeader: ['origin', 'x-requested-with'],
+  checkRateLimit: checkRateLimit,
+  removeHeaders: [
+    'cookie',
+    'cookie2',
+    // Strip Vercel-specific headers that might cause issues
+    'x-vercel-id',
+    'x-vercel-forwarded-for',
+    'x-vercel-deployment-url',
+    'x-vercel-trace',
+    // Keep other headers that might be useful
+  ],
+  redirectSameOrigin: true,
+  httpProxyOptions: {
+    // Vercel handles forwarding headers, so we can keep this
+    xfwd: true,
+  },
+};
+
+// Create the server (this will give us access to the internal handler)
+const server = cors_proxy.createServer(options);
+
+// Extract the request handler from the server
+// This is a bit of a hack, but necessary for Vercel serverless functions
+const requestHandler = server.listeners('request')[0];
+
+module.exports = (req, res) => {
+  // Vercel serverless functions expect the handler to be called directly
+  // But we need to ensure the request URL is properly formatted
+
+  // For Vercel, the path might include the API route prefix
+  // We need to adjust the URL to match what CORS Anywhere expects
+  const originalUrl = req.url;
+  if (req.url.startsWith('/api/')) {
+    // Remove the /api/ prefix for CORS Anywhere
+    req.url = req.url.substring(4);
+  }
+
+  // Call the CORS Anywhere handler
+  requestHandler(req, res);
+};