You can customize the response of HTTP.SYS server using the CustomHeaders property of response object.
Just set the value of CustomHeaders with the Header Name + Header Value separated by NewLine Characters.
Example: if you want to add the following headers, find below a sample code
Access-Control-Allow-Origin: *
Acces-Control-Allow-Methods: GET, POST, OPTIONS, PUT, PATCH, DELETE
private void OnHTTPRequest(TsgcWSConnection_HTTPAPI *aConnection, const THttpServerRequest *aRequestInfo,
ref THttpServerResponse *aResponseInfo)
{
aResponseInfo->ResponseNo = 200;
aResponseInfo->CustomHeaders = "Access-Control-Allow-Origin: *" + #13#10 + "Acces-Control-Allow-Methods: " +
"GET, POST, OPTIONS, PUT, PATCH, DELETE'";
}