Optimizing API Calls with Request Batching

// Client-side code to send batched requests

async function sendBatchedRequests(requests) {
  // 'requests' is an array of objects, e.g.:
  // [{ method: 'GET', path: '/users/1' }, { method: 'POST', path: '/products', body: { name: 'New Item' }}]
  try {
    const response = await fetch('/api/batch', { // Your custom batch endpoint on your backend
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(requests),
    });

    if (!response.ok) {
      throw new Error(`Batch request failed with status: ${response.status}`);
    }

    const data = await response.json();
    console.log('Batched response:', data);
    return data; // 'data' will likely be an array of responses for each original request
  } catch (error) {
    console.error('Error sending batched requests:', error);
    throw error;
  }
}

// --- Example Usage ---
// (async () => {
//   const userRequests = [
//     { method: 'GET', path: '/api/users/1' },
//     { method: 'GET', path: '/api/users/2' },
//     { method: 'POST', path: '/api/products', body: { name: 'Laptop', price: 1200 } }
//   ];

//   try {
//     const batchResults = await sendBatchedRequests(userRequests);
//     // batchResults might look like:
//     // [
//     //   { status: 200, data: { id: 1, name: 'Alice' } },
//     //   { status: 200, data: { id: 2, name: 'Bob' } },
//     //   { status: 201, data: { productId: 'abc', name: 'Laptop' } }
//     // ]
//     console.log('Results of batched operations:', batchResults);
//   } catch (error) {
//     console.error('Failed to get batched results:', error);
//   }
// })();

// --- Hypothetical Server-Side Endpoint (Node.js with Express) ---
/*
const express = require('express');
const axios = require('axios'); // Or fetch, or any HTTP client
const app = express();
app.use(express.json()); // For parsing application/json

app.post('/api/batch', async (req, res) => {
  const requestsToProcess = req.body; // Array of { method, path, body }

  if (!Array.isArray(requestsToProcess)) {
    return res.status(400).json({ error: 'Request body must be an array of requests.' });
  }

  const results = [];
  for (const request of requestsToProcess) {
    try {
      const { method, path, body } = request;
      // IMPORTANT: Validate paths and methods to prevent SSRF or unauthorized access
      // e.g., ensure path starts with '/api/' or is on an allow-list
      if (!path.startsWith('/api/')) {
          results.push({ status: 403, error: 'Unauthorized path' });
          continue;
      }

      const targetUrl = `http://localhost:3000${path}`; // Or your actual internal API base URL
      let apiResponse;

      if (method === 'GET') {
        apiResponse = await axios.get(targetUrl);
      } else if (method === 'POST') {
        apiResponse = await axios.post(targetUrl, body);
      } else if (method === 'PUT') {
          apiResponse = await axios.put(targetUrl, body);
      } else if (method === 'DELETE') {
          apiResponse = await axios.delete(targetUrl);
      } else {
          results.push({ status: 405, error: `Method ${method} not allowed.` });
          continue;
      }

      results.push({ status: apiResponse.status, data: apiResponse.data });
    } catch (error) {
      console.error('Error processing batched request:', error.message);
      results.push({ status: error.response?.status || 500, error: error.message });
    }
  }
  res.json(results);
});

app.listen(3000, () => console.log('Batch server running on port 3000'));
*/