resolveAllowOrigin method
Resolves the Access-Control-Allow-Origin value for origin, or null
when origin is not allowed and no header should be sent.
Implementation
String? resolveAllowOrigin(String origin) {
if (origin.isEmpty) {
return allowOrigin.isEmpty ? '*' : null;
}
if (allowOrigin.isEmpty) return origin;
var o = normalizeOrigin(origin);
var allowed = allowOrigin.any((e) => e == '*' || normalizeOrigin(e) == o);
return allowed ? origin : null;
}