How to Check Session in Controller

[Satish Dasari]

Hi all,

I'm new to struts framework. I'm using struts 1.2.9.
In My application I have many controllers . When the user is logged in I'm setting an session attribute like session.setAttribute("user","true"). And when User logged out I'm removing the attribute from the session.

Here My Problem is.. I want to check the user existence in session for every action. I can check the user in every action writing the code in every method in every Controller, but there are so many Controllers and so many methods. Its difficult to check in every action. Is there any way to check the user in every action before the action is executed and forward the page to some other page. So I need some guidance to check the user in a common class before the action is executed.

Thanks in advance

regrds
Satish Raj

[David Curry]

Satish,

One way to achieve this is through inheritance and overriding. Every struts controller uses the execute() method to perform its duties. You can subclass struts Action, placing all common behavior in the execute() method and having all of your controllers subclass from this one class. The only thing about this is that each controller has its own mapping.findForward() declared in the execute() method - to make this flexible enough for all actions to use we must create an abstract method that will be used in all your controllers.... therefore, your code would have to have all controllers extend the one common class, and change the execute() method to call the abstract method.

It can look something like this:


The BaseAction class is the class all your controllers will extend:

public abstract class BaseAction extends Action {
	
	//Derived class can override this if the action does not require login 
    protected boolean isLoginRequired() {
        return true;
    }
    
    

	public final ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws ServletException {
		
		//if login is required  
        if (isLoginRequired()) {
            //use this or whatever your autherntication code is
            HttpSession session = request.getSession(false);
            if (session == null)
                return mapping.findForward("your_forward_here_for_unsuccessful_login");
        }
        
      //Perform the requested action (implemented in the derived class)
        ActionForward forward = null;
        try {
            forward = performExecute(mapping, form, request, response);
        } catch (Exception e) {
            throw new ServletException(e);
        }
        
		return forward;
	}
	
	
	public abstract ActionForward performExecute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception;
}

Here is an example of one of your existing controller classes:

public class ExistingClassAction extends BaseAction {    //notice we extend BaseAction in place of Action

//uncomment if this action does not require login
//    protected boolean isLoginRequired() {
//        return false;
//    }

        //notice performExecute() is called here in place of execute()
	public ActionForward performExecute(ActionMapping mapping,
								 ActionForm form,
								 HttpServletRequest request,
								 HttpServletResponse response) throws Exception {

			//your existing controller code here...
			
		return mapping.findForward("whatever_mapping_for_thid_controller");
	}
}

It will require your code to change, but once implemented you can place any common code for all controller actions in the BaseAction class without anything changing.

Things to note:
1. This will work on an Action level. Meaning that if the user should be logged in to perform the called action, it will test it.
1. ALL your current controller classes will have to extend BaseAction instead of Action.
2. ALL your current controller classes will have to change the execute() method name to performExecute()
3. If there is a controller that does not require a person to be logged you must override the isLoginRequired() method.

Hope this helps. Let me know how it goes!

~DC

[David Newton]

Or just use a filter.

Checking the session for null, btw, would require all JSPs to turn off automatic session creation.

[David Curry]

David,

Good point regarding the "session == null"; I threw the example together pretty quick.

I actually haven't used Filters; I'm googling it now.

[Kousik Majumder]

Hi,

Can somebody tell me what will be the entry in struts-config.xml for BaseAction.

Actually I have forwarded to error page from BaseAction through struts-config.xml .But it is not happening. Can not understand how the path will be called for BaseAction.

Please help.

Thanks,
Kousik