HTTP header management

When working with HTTP responses, follow these principles for proper header management:

1. Only set default headers when undefined, not when falsy:

   if (!response.getHeader('Content-Type')) {
     response.setHeader('Content-Type', 'application/octet-stream');
   }
   

   This preserves intentionally set falsy values while ensuring compatibility between different HTTP adapters like Express and Fastify.

2. For specialized protocols like Server-Sent Events (SSE), include all necessary headers for proxy compatibility:

   response.writeHead(200, {
     'Content-Type': 'text/event-stream; charset=utf-8',
     'Cache-Control': 'private, no-cache, no-store, must-revalidate, max-age=0, no-transform',
     'X-Accel-Buffering': 'no'
   });
   

   Avoid setting headers that should be determined by the server, such as Transfer-Encoding.

3. For redirects, use standard HTTP status codes with 302 (FOUND) as the default:

   public redirect(response: any, statusCode: number, url: string) {
     const code = statusCode ? statusCode : HttpStatus.FOUND;
     // implementation
   }
   

4. Maintain consistency between different HTTP adapters to ensure predictable behavior across platforms.