How to know if the user is logged in (in the GSP) - grails

Question

I have index.gsp that presents a page. In that page there is a button to register, and a button to log in. Once you have logged in, if the login is ok, the app drives you again to index.gsp. I need that, if the user is logged in, these buttons disappear, and instead say "Hello, [username]". I've tried with this code, but it doesn't work (it is never logged in):
In the Controller:
def dologin(){
def user=Usuario.findByUsernameAndPassword(params.username,springSecurityService.encodePassword(params.password) )
if(user){
redirect (controller:'usuario', action:'index')
}else{
flash.message=message(code:'default.user.not.found', args:[message(code: 'params.username', default:'Usuario'), params.id])
def userlogged = springSecurityService.getCurrentUser()
render view: 'index', model: [user: user]
}
}
In index.gsp (is not full, only the piece that matters):
<sec:ifNotLoggedIn>
<div id="buttons">
<div id="login">Login
</div>
<div id="register">Registrarse
</div>
</div>
</sec:ifNotLoggedIn>
<sec:ifLoggedIn>
<div id="greet">Hello!</div>
</sec:ifLoggedIn>
Any help would be appreciated.
Thank you.

Answer 1

It looks like you're doing your own authentication, rather than going through the spring security authentication process. The <sec:ifLoggedIn> tag relies on spring security handling the authentication.
The usual way this is handled in a spring security app is by posting the login request to /j_spring_security_check, which, behind the scenes, gets filtered by a UsernamePasswordAuthenticationFilter.
Grails and the spring security plugin make this relatively painless by providing a LoginController and auth.gsp that you can use as a starting point. Run the s2-quickstart script (which also creates User and Role domain objects), or just copy them from the spring-security-core templates directory.

Answer 2

I tried it simply
<sec:ifNotLoggedIn> // DO SOMTHING</sec:ifNotLoggedIn>
<sec:ifLoggedIn> // DO SOMTHING</sec:ifNotLoggedIn>

Answer 3

Finally did it simply
<g:if test="${session.user==null}">
<!-- Display buttons-->
</g:if>
<g:if test=${session.user!=null">
<div id="greet"> Hello, ${session.user.username}!</div>
</g:if>
Easier, i think. But, thank you for your answer, ataylor.