Create app.js

app.js

@@ -0,0 +1,125 @@
+// app.js
+const express = require('express');
+const fetch = require('node-fetch');
+const app = express();
+const port = 8080;
+
+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;
+const REFRESH_TOKEN = process.env.REFRESH_TOKEN;
+const API_KEY = process.env.API_KEY;
+
+const TOKEN_URL = 'https://www.googleapis.com/oauth2/v4/token';
+
+let tokenCache = {
+  accessToken: '',
+  expiry: 0,
+  refreshPromise: null
+};
+
+async function getAccessToken() {
+  const now = Date.now() / 1000;
+
+  if (tokenCache.accessToken && now < tokenCache.expiry - 120) {
+    return tokenCache.accessToken;
+  }
+
+  if (tokenCache.refreshPromise) {
+    await tokenCache.refreshPromise;
+    return tokenCache.accessToken;
+  }
+
+  tokenCache.refreshPromise = (async () => {
+    try {
+      const response = await fetch(TOKEN_URL, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json'
+        },
+        body: JSON.stringify({
+          client_id: CLIENT_ID,
+          client_secret: CLIENT_SECRET,
+          refresh_token: REFRESH_TOKEN,
+          grant_type: 'refresh_token'
+        })
+      });
+
+      const data = await response.json();
+      
+      tokenCache.accessToken = data.access_token;
+      tokenCache.expiry = now + data.expires_in;
+    } finally {
+      tokenCache.refreshPromise = null;
+    }
+  })();
+
+  await tokenCache.refreshPromise;
+  return tokenCache.accessToken;
+}
+
+function getLocation() {
+  const currentSeconds = new Date().getSeconds();
+  return currentSeconds < 30 ? 'europe-west1' : 'us-east5';
+}
+
+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');
+});
+
+app.post('/ai/v1/chat/completions', async (req, res) => {
+  const apiKey = req.headers['x-api-key'];
+  if (apiKey !== API_KEY) {
+    return res.status(403).json({
+      type: "error",
+      error: {
+        type: "permission_error",
+        message: "Your API key does not have permission to use the specified resource."
+      }
+    });
+  }
+
+  const accessToken = await getAccessToken();
+  const location = getLocation();
+  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";
+  }
+  
+  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 data = await response.text();
+    res.status(response.status).send(data);
+  } catch (error) {
+    console.error('Error:', error);
+    res.status(500).json({ error: 'Internal Server Error' });
+  }
+});
+
+app.listen(port, () => {
+  console.log(`Server running on port ${port}`);
+});