Create proxy.js

proxy.js

@@ -0,0 +1,94 @@
+const express = require('express');
+const fetch = require('node-fetch');
+
+const app = express();
+const TARGET_URL = 'https://rhknk53jznw37un7.us-east-1.aws.endpoints.huggingface.cloud';
+const MAX_PARALLEL = 4;
+const MAX_WAIT_MS = 10 * 60 * 1000; // 10 minutes
+
+let activeRequests = 0;
+const queue = [];
+
+async function processQueue() {
+  while (queue.length > 0 && activeRequests < MAX_PARALLEL) {
+    const { req, res, next } = queue.shift();
+    activeRequests++;
+    handleRequest(req, res, next).finally(() => {
+      activeRequests--;
+      processQueue();
+    });
+  }
+}
+
+async function retryWith503Backoff(url, options, startTime) {
+  let attempt = 0;
+  
+  while (true) {
+    const elapsed = Date.now() - startTime;
+    if (elapsed > MAX_WAIT_MS) {
+      throw new Error('Max wait time exceeded (10 minutes)');
+    }
+    
+    const response = await fetch(url, options);
+    
+    if (response.status !== 503) {
+      return response;
+    }
+    
+    // Exponential backoff: 1s, 2s, 4s, 8s, 16s, 32s, 64s...
+    const delay = Math.min(1000 * Math.pow(2, attempt), 64000);
+    attempt++;
+    
+    // Check if waiting would exceed max time
+    if (elapsed + delay > MAX_WAIT_MS) {
+      throw new Error('Max wait time would be exceeded');
+    }
+    
+    await new Promise(resolve => setTimeout(resolve, delay));
+  }
+}
+
+async function handleRequest(req, res, next) {
+  try {
+    const startTime = Date.now();
+    const targetUrl = TARGET_URL + req.url;
+    
+    const options = {
+      method: req.method,
+      headers: { ...req.headers, host: new URL(TARGET_URL).host },
+      body: req.method !== 'GET' && req.method !== 'HEAD' ? req.body : undefined
+    };
+    
+    const response = await retryWith503Backoff(targetUrl, options, startTime);
+    
+    res.status(response.status);
+    response.headers.forEach((value, key) => {
+      res.setHeader(key, value);
+    });
+    
+    response.body.pipe(res);
+  } catch (error) {
+    res.status(504).json({ error: error.message });
+  }
+}
+
+app.use(express.raw({ type: '*/*', limit: '50mb' }));
+
+app.use((req, res, next) => {
+  if (activeRequests < MAX_PARALLEL) {
+    activeRequests++;
+    handleRequest(req, res, next).finally(() => {
+      activeRequests--;
+      processQueue();
+    });
+  } else {
+    queue.push({ req, res, next });
+  }
+});
+
+const PORT = process.env.PORT || 7860;
+app.listen(PORT, () => {
+  console.log(`Reverse proxy listening on port ${PORT}`);
+  console.log(`Proxying to: ${TARGET_URL}`);
+  console.log(`Max parallel requests: ${MAX_PARALLEL}`);
+});