Update app.js

app.js

@@ -1,10 +1,12 @@
-// app.js
 const express = require('express');
 const fetch = require('node-fetch');
+const bodyParser = require('body-parser');
+
 const app = express();
-const port = 8080;
+app.use(bodyParser.json());
 
 const MODEL = 'claude-3-5-sonnet@20240620';
+
 const PROJECT_ID = process.env.PROJECT_ID;
 const CLIENT_ID = process.env.CLIENT_ID;
 const CLIENT_SECRET = process.env.CLIENT_SECRET;
@@ -47,7 +49,6 @@ async function getAccessToken() {
       });
 
       const data = await response.json();
-      
       tokenCache.accessToken = data.access_token;
       tokenCache.expiry = now + data.expires_in;
     } finally {
@@ -68,13 +69,11 @@ function constructApiUrl(location) {
   return `https://${location}-aiplatform.googleapis.com/v1/projects/${PROJECT_ID}/locations/${location}/publishers/anthropic/models/${MODEL}:streamRawPredict`;
 }
 
-app.use(express.json());
-
-app.get('/', (req, res) => {
-  res.status(200).send('Vertex Claude API From GCP');
-});
+async function handleRequest(req, res) {
+  if (req.method === 'OPTIONS') {
+    return handleOptions(res);
+  }
 
-app.post('/ai/v1/messages', async (req, res) => {
   const apiKey = req.headers['x-api-key'];
   if (apiKey !== API_KEY) {
     return res.status(403).json({
@@ -91,35 +90,47 @@ app.post('/ai/v1/messages', async (req, res) => {
   const apiUrl = constructApiUrl(location);
 
   let requestBody = req.body;
-  
+
   if (requestBody.anthropic_version) {
     delete requestBody.anthropic_version;
   }
-  
-  if (requestBody.model === "claude-3-5-sonnet-20240620") {
-    requestBody.model = "claude-3-5-sonnet@20240620";
+
+  if (requestBody.model) {
+    delete requestBody.model;
   }
-  
+
   requestBody.anthropic_version = "vertex-2023-10-16";
 
-  try {
-    const response = await fetch(apiUrl, {
-      method: 'POST',
-      headers: {
-        'Authorization': `Bearer ${accessToken}`,
-        'Content-Type': 'application/json; charset=utf-8'
-      },
-      body: JSON.stringify(requestBody)
-    });
+  const modifiedHeaders = {
+    'Authorization': `Bearer ${accessToken}`,
+    'Content-Type': 'application/json; charset=utf-8'
+  };
 
-    const data = await response.text();
-    res.status(response.status).send(data);
-  } catch (error) {
-    console.error('Error:', error);
-    res.status(500).json({ error: 'Internal Server Error' });
-  }
-});
+  const response = await fetch(apiUrl, {
+    headers: modifiedHeaders,
+    method: 'POST',
+    body: JSON.stringify(requestBody)
+  });
 
-app.listen(port, () => {
-  console.log(`Server running on port ${port}`);
+  const responseBody = await response.text();
+  res.status(response.status).set(response.headers).send(responseBody);
+}
+
+function handleOptions(res) {
+  res.setHeader('Access-Control-Allow-Origin', '*');
+  res.setHeader('Access-Control-Allow-Methods', 'POST, GET, OPTIONS');
+  res.setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization, x-api-key, anthropic-version, model');
+  res.sendStatus(204);
+}
+
+app.post('/ai/v1/messages', handleRequest);
+app.options('/ai/v1/messages', handleOptions);
+
+app.get('/', (req, res) => {
+  res.status(200).send('Vertex Claude API Proxy');
 });
+
+const PORT = process.env.PORT || 8080;
+app.listen(PORT, () => {
+  console.log(`Server is running on port ${PORT}`);
+});