dsShelfCorsPreflightResponse function
Generates a CORS preflight (OPTIONS) Response using default headers.
Implementation
Response dsShelfCorsPreflightResponse(Request request) {
final origin = request.headers[dsShelfOriginHeader];
if (origin == null) {
// No Origin header → not a valid CORS preflight
return Response(400, body: 'Missing Origin header');
}
return Response.ok(null, headers: _buildPreflightHeaders(origin));
}