How to include Spring Security in a spring boot application - maven

Question

I am working of a spring boot application. After developing the application, we are now trying to include spring security in our application.
I have included the following code:
html code:
<li th:if="${#authorization.expression('!isAuthenticated()')}">
<a th:href="#{/login}" th:text="#{navbar.login.text}" />
</li>
Java code:
package com.devopsbuddy.config;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
#Configuration
#EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
private static final String[] PUBLIC_MATCHERS = {
"/webjars/**",
"/css/**",
"/js/**",
"/images/**",
"/",
"/about/**",
"/contact/**",
"/error/**/*"
};
#Override
protected void configure(HttpSecurity http) throws Exception {
http
.authorizeRequests()
.antMatchers(PUBLIC_MATCHERS).permitAll()
.anyRequest().authenticated()
.and()
.formLogin().loginPage("/login").defaultSuccessUrl("/payload")
.failureUrl("/login?error").permitAll()
.and()
.logout().permitAll();
}
#Autowired
public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
auth
.inMemoryAuthentication()
.withUser("user").password("password")
.roles("USER");
}
}
when I try to hit the url:
http://localhost:8080/
I am getting the below error on screen:
**36673 [http-nio-8080-exec-2] ERROR org.thymeleaf.TemplateEngine - [THYMELEAF][http-nio-8080-exec-2] Exception processing template "user/login": Exception evaluating SpringEL expression: "#authorization.expression('!isAuthenticated()')" (template: "common/navbar" - line 24, col 25)
org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating SpringEL expression: "#authorization.expression('!isAuthenticated()')" (template: "common/navbar" - line 24, col 25)
at org.thymeleaf.spring5.expression.SPELVariableExpressionEvaluator.evaluate(SPELVariableExpressionEvaluator.java:290)
at org.thymeleaf.standard.expression.VariableExpression.executeVariableExpression(VariableExpression.java:166)
at org.thymeleaf.standard.expression.SimpleExpression.executeSimple(SimpleExpression.java:66)
at org.thymeleaf.standard.expression.Expression.execute(Expression.java:109)
at org.thymeleaf.standard.expression.Expression.execute(Expression.java:138)
at org.thymeleaf.standard.expression.Expression.execute(Expression.java:125)
...
...
Caused by: org.springframework.expression.spel.SpelEvaluationException: EL1011E: Method call: Attempted to call method expression(java.lang.String) on null context object
at org.springframework.expression.spel.ast.MethodReference.throwIfNotNullSafe(MethodReference.java:153)
at org.springframework.expression.spel.ast.MethodReference.getValueRef(MethodReference.java:82)
at org.springframework.expression.spel.ast.CompoundExpression.getValueRef(CompoundExpression.java:67)
at org.springframework.expression.spel.ast.CompoundExpression.getValueInternal(CompoundExpression.java:88)
at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:111)
at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:328)
at org.thymeleaf.spring5.expression.SPELVariableExpressionEvaluator.evaluate(SPELVariableExpressionEvaluator.java:263)
... 102 common frames omitted
36673 [http-nio-8080-exec-2] ERROR o.a.c.c.C.[.[.[.[dispatcherServlet] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.thymeleaf.exceptions.TemplateProcessingException: Exception evaluating SpringEL expression: "#authorization.expression('!isAuthenticated()')" (template: "common/navbar" - line 24, col 25)] with root cause
org.springframework.expression.spel.SpelEvaluationException: EL1011E: Method call: Attempted to call method expression(java.lang.String) on null context object
at org.springframework.expression.spel.ast.MethodReference.throwIfNotNullSafe(MethodReference.java:153)
at org.springframework.expression.spel.ast.MethodReference.getValueRef(MethodReference.java:82)
at org.springframework.expression.spel.ast.CompoundExpression.getValueRef(CompoundExpression.java:67)**
pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.thymeleaf.extras</groupId>
<artifactId>thymeleaf-extras-springsecurity4</artifactId>
<version>2.1.2.RELEASE</version>
</dependency>
I am new to Thymeleaf and Spring security. So not sure why the Spring security is failing.
If i comment the line with authorization.expression(), it works.
I have shared the code at https://github.com/azaveri7/devopsbuddy in branch security.
Please advise.

Answer 1

please consider this as a suggestion, not an answer. previously I also went through this but hard to figure it out. then I decided to go through spring's automatic configurations. I only used this library -
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
and then spring provided the login URL, login page, logout URL etc.. I only wrote the userdetailsService. and in my case, I also wrote a custom filter also.

Answer 2

The spring security is 5.0.9 in your pom that extend the spring-boot-starter-parent 2.0.6
BUT thymeleaf-extras-springsecurity4 is still spring security 4, so you need to upgrade the thymeleaf-extras to
<dependency>
<groupId>org.thymeleaf.extras</groupId>
<artifactId>thymeleaf-extras-springsecurity5</artifactId>
<version>3.0.4.RELEASE</version>
</dependency>

Answer 3

I have the below to check if user is not logged-in or not
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:th="http://www.thymeleaf.org"
xmlns:sec="http://www.thymeleaf.org/thymeleaf-extras-springsecurity4">
....
<span sec:authorize="not isAuthenticated()">
You are not logged in - click <a th:href="#{/login}">login</a>
</span>
...