server.py

#!/usr/bin/env python3
"""
Simple HTTP server with Cross-Origin Isolation headers for SharedArrayBuffer.
This enables multi-threading in ONNX Runtime Web for much better performance.
"""

import http.server
import socketserver
import sys

PORT = int(sys.argv[1]) if len(sys.argv) > 1 else 8080


class CORSRequestHandler(http.server.SimpleHTTPRequestHandler):
    def end_headers(self):
        # Required for SharedArrayBuffer (enables multi-threading in WASM)
        self.send_header('Cross-Origin-Opener-Policy', 'same-origin')
        self.send_header('Cross-Origin-Embedder-Policy', 'require-corp')
        # Allow loading from CDN
        self.send_header('Access-Control-Allow-Origin', '*')
        super().end_headers()

    def do_OPTIONS(self):
        self.send_response(200)
        self.end_headers()


if __name__ == '__main__':
    class ReusableTCPServer(socketserver.TCPServer):
        allow_reuse_address = True
    with ReusableTCPServer(("", PORT), CORSRequestHandler) as httpd:
        print(f"Serving at http://localhost:{PORT}")
        print("Cross-Origin Isolation headers enabled for multi-threading")
        print("Press Ctrl+C to stop")
        try:
            httpd.serve_forever()
        except KeyboardInterrupt:
            print("\nShutting down...")