[FIXED] Get Cookie after its set in doFilter

Issue

I have a CookieFilter class that overrides doFilter method to set a Cookie before my Rest service is invoked:

import javax.servlet.*;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.UUID;

public class CookieFilter implements Filter {

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

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) 
         throws IOException, ServletException {

        HttpServletRequest httpRequest = (HttpServletRequest) request;
        HttpServletResponse httpResponse = (HttpServletResponse) response;

        if (notPresent("TEST")) {
             String uuid = UUID.randomUUID().toString();
             httpResponse.addCookie(new Cookie("TEST", uuid));
        }

        chain.doFilter(request, response);
    }

    @Override
    public void destroy() {}

    private boolean notPresent(String cookieName) {
         // here are the checks
    }
}

Rest service method:

void myRestServiceMethod(@Context HttpServletRequest request) {
   Cookie[] cookies = request.getCookies(); // has my cookie inside after second call
   // other logic bellow
}

myRestServiceMethod is called after doFilter but Cookie is not present.

However, I am able to read the cookie (using JAX-RS @Context to retrieve HttpServletRequest object) in second client call to myRestServiceMethod where Cookie (set in a first call) is sent from the client and passed to the server.

My question is: is there a way read the Cookie in a first call to myRestServiceMethod after its set in doFilter?

Solution

is there a way read the Cookie in a first call to myRestServiceMethod after its set in doFilter?

No.

There are 2 solutions:

1. Refresh the request after adding cookie.

   if (notPresent("TEST")) {
       String uuid = UUID.randomUUID().toString();
       httpResponse.addCookie(new Cookie("TEST", uuid));
       httpRequest.sendRedirect(httpRequest.getRequestURI()); // NOTE: you might want to add query string if necessary.
   }
   else {
       chain.doFilter(request, response);
   }
   

2. Or, better, store it as request attribute.

   String uuid = getCookieValue("TEST");
   
   if (uuid == null) {
       uuid = UUID.randomUUID().toString();
       httpResponse.addCookie(new Cookie("TEST", uuid));
   }
   
   request.setAttribute("TEST", uuid);
   chain.doFilter(request, response);
   

   So that you can simply do this.

   String uuid = (String) request.getAttribute("TEST");
   

   If CDI is available in the environment, you could populate a @RequestScoped bean instead.

That said, it's strange to have a JAX-RS service to (indirectly) deal with cookies. REST is never intented to be stateful.

Answered By - BalusC
Answer Checked By - Terry (JavaFixing Volunteer)