Stripes and Shiro

I've been a long-time fan of Stripes, a really simple but powerful way of doing web apps in Java. It throws away complicated XML configuration and just prefers convention over configuration and uses annotations heavily to denote actions. It's clean cut and fast to develop in. However, it doesn't really do security (as in authentication and access control), but leaves those to the application.

Enter Apache Shiro (incubation), which is another really simple but powerful library to add access control and authentication to your Java application. It's not limited to webapps, but can be used in anything - though I don't think too many people are doing Java clients these days anymore.

Shiro comes with Spring integration built-in, but I figured I should try to make it Stripes-compatible too. Turns out this was a fairly easy task, though it was made a bit extra difficult by the fact that the AOP libraries of Shiro are not very well documented.

The way this works is that you add a new Stripes Interceptor that just delegates the access control checking to Shiro at just the right point. It even uses Shiro's built-in annotations, so it's fairly simple. Just add the following class to whichever package you like and play with it.

package stripes.util;

import java.lang.reflect.Method;

import net.sourceforge.stripes.action.Resolution;
import net.sourceforge.stripes.controller.ExecutionContext;
import net.sourceforge.stripes.controller.Interceptor;
import net.sourceforge.stripes.controller.Intercepts;
import net.sourceforge.stripes.controller.LifecycleStage;

import org.apache.shiro.aop.MethodInvocation;
import org.apache.shiro.authz.aop.AnnotationsAuthorizingMethodInterceptor;

/**
 *  A Stripes Interceptor which will check if the given handler method has a {@link Require}
 *  annotation, and checks from Shiro whether the user has access to it.  For example
 *  <pre>
 *     public class AdminActionBean implements ActionBean
 *     {
 *        @DefaultHandler
 *        @RequiresRoles("admin")
 *        public Resolution doAdminThingies()
 *        {
 *           ...
 *        }
 *     }
 *  </pre>
 */
@Intercepts(LifecycleStage.HandlerResolution)
public class AccessInterceptor extends AnnotationsAuthorizingMethodInterceptor implements Interceptor
{
    public Resolution intercept( ExecutionContext ctx ) throws Exception
    {
        // First, execute the HandlerResolution
        Resolution resolution = ctx.proceed();

        MethodInvocation mi = new StripesMethodInvocation( ctx );
        
        // This throws a SecurityException if there's no access, which will
        // be caught by the ShiroFilter and acted upon.
        assertAuthorized( mi );
        
        return resolution;
    }
    
    /**
     *  Private class which wraps the current ActionBean/Method invocation
     *  information into a Shiro MethodInvocation.
     */
    private static class StripesMethodInvocation implements MethodInvocation
    {
        private ExecutionContext m_context;
        
        public StripesMethodInvocation(ExecutionContext ctx)
        {
            m_context = ctx;
        }

        public Object[] getArguments()
        {
            // Stripes handlers never get arguments, so this is cool.
            return null;
        }

        public Method getMethod()
        {
            return m_context.getHandler();
        }

        public Object getThis()
        {
            return m_context.getActionBean();
        }

        public Object proceed() throws Throwable
        {
            // This is not actually used by us
            return null;
        }
        
    }
}

Enjoy :-)




Comments

Thank You!

--Anonymous Regexp, 30-Sep-2010


Pretty cool

--AnonymousCoward, 12-Dec-2010


Hi,

Thanks for the code, I've used it (with an acknowledgement!) in my webapp, however I have a bug that I don't see how your code would get around. Shiro uses a ThreadLocal object to store the current subject SecurityUtils.getSubject() and uses this subject to do authorization with. However, you aren't guaranteed that the same thread will be used to service the same session.

I'm seeing the same user serviced by different threads and therefore their authentication token is invalid and they are asked to login again, how have you overcome this?

Do you store some kind of lookup between session and subject and access this somewhere else?

Thanks,

-James

--James B, 20-Dec-2011


Sorry, I didn't see this comment until now. The DefaultWebSecurityManager stores the subject in the Session object, perhaps you should use that instead of the DefaultSecurityManager?

--JanneJalkanen, 18-Jan-2012


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"Main_blogentry_100910_1" last changed on 10-Sep-2010 23:20:48 EEST by JanneJalkanen.

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