Thymeleaf - Spring Security 3 integration module

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Status

This is a thymeleaf extras module, not a part of the Thymeleaf core (and as such following its own versioning schema), but fully supported by the Thymeleaf team.

Current versions:

• Version 2.0.0 - for Thymeleaf 2.0 (requires 2.0.14+)

License

This software is licensed under the [Apache License 2.0] (http://www.apache.org/licenses/LICENSE-2.0.html).

Requirements

• Thymeleaf 2.0.14+
• Spring Security version 3.0.x, 3.1.1+, 3.2.x
• Web environment (Spring Security integration cannot work offline)

Maven info

• groupId: org.thymeleaf.extras
• artifactId: thymeleaf-extras-springsecurity3

Distribution packages

Distribution packages (binaries + sources + javadoc) can be downloaded from SourceForge.

Features

This module provides a new dialect called org.thymeleaf.extras.springsecurity3.dialect.SpringSecurityDialect, with default prefix sec. It includes:

• New expression utility objects: * #authentication representing the Spring Security authentication object (an object implementing the org.springframework.security.core.Authentication interface). * #authorization: a expression utility object with methods for checking authorization based on expressions, URLs and Access Control Lists.
• New attributes: * sec:authentication="prop" outputs a prop property of the authentication object, similar to the Spring Security <sec:authentication/> JSP tag. * sec:authorize="expr" or sec:authorize-expr="expr" renders the element children (tag content) if the authenticated user is authorized to see it according to the specified Spring Security expression. * sec:authorize-url="url" renders the element children (tag content) if the authenticated user is authorized to see the specified URL. * sec:authorize-acl="object :: permissions" renders the element children (tag content) if the authenticated user has the specified permissions on the specified domain object, according to Spring Source's Access Control List system.

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Configuration

In order to use the thymeleaf-extras-springsecurity3 module in your Spring MVC application, we will first need to configure our application in the usual way for Spring + Thymeleaf applications (TemplateEngine bean, template resolvers, etc.), and add the SpringSecurity dialect to our Template Engine so that we can use the sec:* attributes and special expression utility objects:

    <bean id="templateEngine" class="org.thymeleaf.spring3.SpringTemplateEngine">
      ...
      <property name="additionalDialects">
        <set>
          <bean class="org.thymeleaf.extras.springsecurity3.dialect.SpringSecurityDialect"/>
        </set>
      </property>
	  ...
    </bean>

And that's all!

Using the expression utility objects

The #authentication object can be easily used, like this:

    <div th:text="${#authentication.name}">
        The value of the "name" property of the authentication object should appear here.
    </div>

The #authorization object can be used in a similar way, normally in th:if or th:unlesstags:

    <div th:if="${#authorization.expression('hasRole(''ROLE_ADMIN'')')}">
        This will only be displayed if authenticated user has role ROLE_ADMIN.
    </div>

The #authorization object is an instance of org.thymeleaf.extras.springsecurity3.auth.Authorization, see this class and its documentation to understand all the methods offered.

Using the attributes

Using the sec:authentication attribute is equivalent to using the #authentication object, but using its own attribute:

    <div sec:authentication="name">
        The value of the "name" property of the authentication object should appear here.
    </div>

The sec:authorize and sec:authorize-expr attributes are exactly the same. They work equivalently to a th:if that evaluated an #authorization.expression(...) expression, by evaluating a Spring Security Expression:

    <div sec:authorize="hasRole('ROLE_ADMIN')">
        This will only be displayed if authenticated user has role ROLE_ADMIN.
    </div>

These Spring Security Expressions in sec:authorize attributes are in fact Spring EL expressions evaluated on a SpringSecurity-specific root object containing methods such as hasRole(...), getPrincipal(), etc.

As with normal Spring EL expressions, Thymeleaf allows you to access a series of objects from them including the context variables map (the #vars object). In fact, you are allowed to surround your access expression with ${...} if it makes you feel more comfortable:

    <div sec:authorize="${hasRole(#vars.expectedRole)}">
        This will only be displayed if authenticated user has a role computed by the controller.
    </div>

Remember that Spring Security sets a special security-oriented object as expression root, which is why you would not be able to access the expectedRole variable directly in the above expression.

Another way of checking authorization is sec:authorize-url, which allows you to check whether a user is authorized to visit a specific URL or not:

    <div sec:authorize-url="/admin">
        This will only be displayed if authenticated user can call the "/admin" URL.
    </div>

For specifying a specific HTTP method, do:

    <div sec:authorize-url="POST /admin">
        This will only be displayed if authenticated user can call the "/admin" URL
        using the POST HTTP method.
    </div>

Finally, there is an attribute for checking authorization using Spring Security's Access Control Lists, which needs the specification of a domain object and the permissions defined on it that we are asking for.

    <div sec:authorize-acl="${obj} :: '1,3'">
        This will only be displayed if authenticated user has permissions "1" and "3"
        on domain object referenced by context variable "obj".
    </div>

In this attribute, both domain object and permission specifications are considered to be thymeleaf Standard Expressions.