import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

import com.google.inject.Singleton;

/**
 * Allow CORS for Swagger specification api.
 *
 * @author ben.manes@gmail.com (Ben Manes)
 */
@Singleton
final class ApiOriginFilter implements Filter {

  @Override
  public void doFilter(ServletRequest request, ServletResponse response,
      FilterChain chain) throws IOException, ServletException {
    HttpServletResponse res = (HttpServletResponse) response;
    res.addHeader("Access-Control-Allow-Origin", "*");
    res.addHeader("Access-Control-Allow-Headers", "Content-Type");
    res.addHeader("Access-Control-Allow-Methods", "GET, POST, DELETE, PUT");
    chain.doFilter(request, response);
  }

  @Override
  public void destroy() {}

  @Override
  public void init(FilterConfig filterConfig) throws ServletException {}
}