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[[core-securityTagLib]]
=== SecurityTagLib

The plugin includes GSP tags to support conditional display based on whether the user is authenticated, and/or has the required role to perform a particular action. These tags are in the `sec` namespace and are implemented in `grails.plugin.springsecurity.SecurityTagLib`.

==== ifLoggedIn
Displays the inner body content if the user is authenticated.

Example:

[source,html]
.Listing {counter:listing}. Example using `<sec:ifLoggedIn>`
----
<sec:ifLoggedIn>
Welcome Back!
</sec:ifLoggedIn>
----

==== ifNotLoggedIn
Displays the inner body content if the user is not authenticated.

Example:

[source,html]
.Listing {counter:listing}. Example using `<sec:ifNotLoggedIn>`
----
<sec:ifNotLoggedIn>
<g:link controller='login' action='auth'>Login</g:link>
</sec:ifNotLoggedIn>
----

==== ifAllGranted
Displays the inner body content only if all of the listed roles are granted.

Example:

[source,html]
.Listing {counter:listing}. Example using `<sec:ifAllGranted>`
----
<sec:ifAllGranted roles='ROLE_ADMIN,ROLE_SUPERVISOR'>
...
secure stuff here
...
</sec:ifAllGranted>
----

==== ifAnyGranted
Displays the inner body content if at least one of the listed roles are granted.

Example:

[source,html]
.Listing {counter:listing}. Example using `<sec:ifAnyGranted>`
----
<sec:ifAnyGranted roles='ROLE_ADMIN,ROLE_SUPERVISOR'>
...
secure stuff here
...
</sec:ifAnyGranted>
----

==== ifNotGranted
Displays the inner body content if none of the listed roles are granted.

Example:

[source,html]
.Listing {counter:listing}. Example using `<sec:ifNotGranted>`
----
<sec:ifNotGranted roles='ROLE_USER'>
...
non-user stuff here
...
</sec:ifNotGranted>
----

==== loggedInUserInfo
Displays the value of the specified UserDetails property if logged in. For example, to show the username property:

[source,html]
.Listing {counter:listing}. Example using `<sec:loggedInUserInfo>`
----
<sec:loggedInUserInfo field='username'/>
----

If you have customized the UserDetails (e.g. with a custom UserDetailsService) to add a `fullName` property, you access it as follows:

[source,html]
.Listing {counter:listing}. Example using `<sec:loggedInUserInfo>` for a nonstandard property
----
Welcome Back <sec:loggedInUserInfo field='fullName'/>
----

[[core-taglib-username]]
==== username
Displays the value of the UserDetails `username` property if logged in.

[source,html]
.Listing {counter:listing}. Example using `<sec:username>`
----
<sec:ifLoggedIn>
Welcome Back <sec:username/>!
</sec:ifLoggedIn>
<sec:ifNotLoggedIn>
<g:link controller='login' action='auth'>Login</g:link>
</sec:ifNotLoggedIn>
----

==== ifSwitched
Displays the inner body content only if the current user switched from another user. (See also <<core-switchUser>>.)

[source,html]
.Listing {counter:listing}. Example using `<sec:ifSwitched>` and `<sec:ifNotSwitched>`
----
<sec:ifLoggedIn>
Logged in as <sec:username/>
</sec:ifLoggedIn>

<sec:ifSwitched>
    <form action='${request.contextPath}/logout/impersonate' method='POST'>
        <input type='submit' value="Resume as ${grails.plugin.springsecurity.SpringSecurityUtils.switchedUserOriginalUsername}"/>
    </form>
</sec:ifSwitched>

<sec:ifNotSwitched>

   <sec:ifAllGranted roles='ROLE_SWITCH_USER'>

   <form action='${request.contextPath}/login/impersonate'
         method='POST'>

      Switch to user: <input type='text' name='username'/><br/>

      <input type='submit' value='Switch'/> </form>

   </sec:ifAllGranted>

</sec:ifNotSwitched>
----

==== ifNotSwitched
Displays the inner body content only if the current user has not switched from another user.

==== switchedUserOriginalUsername
Renders the original user's username if the current user switched from another user.

[source,html]
.Listing {counter:listing}. Example using `<sec:switchedUserOriginalUsername>`
----
<sec:ifSwitched>
    <form action='${request.contextPath}/logout/impersonate' method='POST'>
        <input type='submit' value="Resume as ${grails.plugin.springsecurity.SpringSecurityUtils.switchedUserOriginalUsername}"/>
    </form>
</sec:ifSwitched>
----

==== access

Renders the body if the specified expression evaluates to `true` or specified URL is allowed.

[source,html]
.Listing {counter:listing}. Example using `<sec:access>` with an expression
----
<sec:access expression="hasRole('ROLE_USER')">

You're a user

</sec:access>
----

[source,html]
.Listing {counter:listing}. Example using `<sec:access>` with a URL
----
<sec:access url='/admin/user'>

<g:link controller='admin' action='user'>Manage Users</g:link>

</sec:access>
----

You can also guard access to links generated from controller and action names or named URL mappings instead of hard-coding the values, for example

[source,html]
.Listing {counter:listing}. Example using `<sec:access>` with a controller and action
----
<sec:access controller='admin' action='user'>

<g:link controller='admin' action='user'>Manage Users</g:link>

</sec:access>
----

or if you have a named URL mapping you can refer to that:

[source,html]
.Listing {counter:listing}. Example using `<sec:access>` with a URL mapping
----
<sec:access mapping='manageUsers'>

<g:link mapping='manageUsers'>Manage Users</g:link>

</sec:access>
----

For even more control of the generated URL (still avoiding hard-coding) you can use `createLink` to build the URL, for example

[source,html]
.Listing {counter:listing}. Example using `<sec:access>` with `<g:createLink>`
----
<sec:access url='${createLink(controller: 'admin', action: 'user', base: '/')}'>

<g:link controller='admin' action='user'>Manage Users</g:link>

</sec:access>
----

Be sure to include the `base: '/'` attribute in this case to avoid appending the context name to the URL.

==== noAccess

Renders the body if the specified expression evaluates to `false` or URL isn't allowed.

[source,html]
.Listing {counter:listing}. Example using `<sec:noAccess>`
----
<sec:noAccess expression="hasRole('ROLE_USER')">

You're not a user

</sec:noAccess>
----

==== link

A wrapper around the standard Grails link tag that renders if the specified expression evaluates to `true` or URL is allowed.

To define the expression to evaluate within the tag itself:

[source,html]
.Listing {counter:listing}. Example using `<sec:link>` with an expression
----
<sec:link controller='myController' action='myAction' expression="hasRole('ROLE_USER')">My link text</sec:link>
----

To use access controls defined, for example, in the interceptUrlMap:

[source,html]
.Listing {counter:listing}. Example using `<sec:link>` without an expression
----
<sec:link controller='myController' action='myAction'>My link text</sec:link>
----

By default, nothing will be rendered if the specified expression evaluates to `false` or URL is not allowed. To render only the text that would have been linked, set the `fallback` attribute:
[source,html]
.Listing {counter:listing}. Example using `<sec:link fallback='true'>` without an expression
----
<sec:link controller='myController' action='myAction' fallback='true'>This text will display but won't be linked if the user doesn't have access</sec:link>
----