Claude proxy service to support CORS

claude_proxy_service.ts

import { serve } from 'https://deno.land/[email protected]/http/server.ts';

const PORT = 8088;
const ALLOWED_HEADERS = ['x-api-key', 'anthropic-version', 'Content-Type'];

function addCORSHeaders(responseHeaders: Headers) {
    responseHeaders.set('Access-Control-Allow-Origin', '*'); // Allow requests from any origin
    responseHeaders.set('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS'); // Allowed methods
    responseHeaders.set('Access-Control-Allow-Headers', '*'); // Allow all headers
}

const handleRequest = async (request: Request): Promise<Response> => {
    if (request.method == 'OPTIONS') {
        console.log('Received OPTIONS request');
        // Add CORS headers
        const responseHeaders = new Headers();
        addCORSHeaders(responseHeaders);

        return new Response(null, {
            status: 200,
            headers: responseHeaders,
        });
    }
    const targetURL = request.headers.get('x-url');
    console.log('Received request', targetURL);

    if (!targetURL) {
        return new Response("Please provide an 'x-url' header.", { status: 400 });
    }

    const requestHeaders = new Headers();
    for (const [key, value] of request.headers.entries()) {
        if (ALLOWED_HEADERS.includes(key.toLowerCase())) {
            requestHeaders.set(key, value);
        }
    }
    const requestBody = request.body ? await request.arrayBuffer() : undefined;

    const proxyRequest = new Request(targetURL, {
        method: request.method,
        headers: requestHeaders,
        body: requestBody,
    });

    const proxyResponse = await fetch(proxyRequest);
    const responseHeaders = new Headers(proxyResponse.headers);
    const responseBody = proxyResponse.body;

    // Add CORS headers
    addCORSHeaders(responseHeaders);

    return new Response(responseBody, {
        status: proxyResponse.status,
        headers: responseHeaders,
    });
};

console.log(`Proxy server listening on http://localhost:${PORT}`);
await serve(handleRequest, { port: PORT });