It’s Only Software

Interestingly, a month or so after I posted my 5 Minute Guide to Spring Security 2, a commonly asked question was asked on the Spring forums. I figured I’d address it here, because (once again in Spring/Acegi Security integration) the answer wasn’t really obvious.

Essentially, the question goes something like this:

The examples I can find using Spring Security show this “login.jsp” page. How can I pull Spring content into this page?

Typically, you might want to display data on the login page that’s provided by Spring service-layer beans, or tie into the i18n bundles you’ve configured, or tens of other possibilities.

Fortunately, this is possible with a few tweaks to your Spring configuration. In this post, I’ll assume you’ve started with the configuration I wrote up in the initial 5 Minute Guide to Spring Security.

First, as with any Spring action, you will need a controller to handle the Login page display (the form POST is handled by the Spring Security interceptor). A simple annotated controller might look like this:

/**
 * Simple mapping for login page.
 * 
 * @author Mularien
 */
@Controller
public class LoginController {
	private static Logger logger = Logger.getLogger(LoginController.class);
 
	@Autowired
	// stuff required to display header, footer, etc.
 
	@RequestMapping("/login.do")
	public void login() {
 
	}
 
	@RequestMapping("/accessDenied.do")
	public ModelAndView accessDenied() {
		return new ModelAndView("redirect:/index.do");
	}
}

Now, you can see where we’re going with this. We’ll need a corresponding “login.jsp” page in our views directory, so that the “login.do” mapping works. You’ll need to tweak your Spring Security configuration:

    <http auto-config="true" access-denied-page="/accessDenied.do">
        <intercept-url pattern="/login.do*" filters="none"/>  
        <intercept-url pattern="/app/*.do" access="ROLE_USER,ROLE_ADMIN"  />
        <intercept-url pattern="/admin/**/*.do" access="ROLE_ADMIN"  />
    	<form-login login-page="/login.do" authentication-failure-url="/login.do?login_error=1"
    	   default-target-url="/app/index.do"/>
    	<logout logout-success-url="/login.do"/>
    </http>

Note the references to “login.do” and “accessDenied.do” here – these are the mappings we set up in our login controller. Pay attention to the access rules we’ve assigned – the URL intercept for “/login.do*” has no authorization checks applied to it, this is important otherwise users won’t be able to access the login page!

Hope this helps someone! As always, your comments are appreciated.

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