Can we use spring data repository to update embedded documents in mongodb

Can we use spring data repository to update embedded documents in mongodb

Can we use spring data repository to update embedded documents in mongodb

    {
    "_id" : 1000,
    "user_id" : "001",
    "events" : [
            {
                    "handled" : 1,
                    "profile" : 10,
                    "data" : "....."
            }
            {
                    "handled" : 1,
                    "profile" : 10,
                    "data" : "....."
            }
            {
                    "handled" : 1,
                    "profile" : 20,
                    "data" : "....."
            }
            ...
       ]
}

I want to update the handle to 10 where events.profile is 10. I know how to do it using mongoTemplate but i need to know how to do it using mongoRepository. Thanks

Build Web App Authentication using Spring Boot, Spring Security, MongoDB and Angular 8

Build Web App Authentication using Spring Boot, Spring Security, MongoDB and Angular 8

In this article, you'll learn how to build web application authentication using Spring Boot, Spring Security, MongoDB, and Angular 8

In this tutorial, we have to build Spring Boot, Spring Security Core, and MongoDB RESTful Authentication as the backend. The Angular 8 used as the frontend using the HttpClient, HttpInterceptor, and RouteGuard modules. The secure page guarded by Angular 8 Route Guard and the secure RESTful API guarded by Spring Security REST. This should be a great combination of a secure modern web application.

The flow of the web application looks like below Sequence Diagram.

The Angular 8 application starts with the secure and route guarded page list of products without authorization headers. The Angular 8 redirect to the Login page. After login with the valid credential, the Angular 8 got the JWT token that validates with Route guard also send together with Authorization headers bearer. In the products list page, the Angular 8 application request products API to Spring Boot Security API include authorization headers. Finally, the Angular 8 page displaying the list of products.

The following tools, frameworks, libraries, and modules are required for this tutorial:

We assume that you already installed all required software, tools, and frameworks. So, we will not cover how to install that software, tools, and frameworks. Notes: We are using Spring Boot 2.1.6 (Stable version), JDK 1.8.0_92, and Angular 8.0.6.

Generate a New Spring Boot Gradle Project

To create or generate a new Spring Boot Application or Project, simply go to Spring Initializer. Fill all required fields as below then click on Generate Project button.

The project will automatically be downloaded as a Zip file. Next, extract the zipped project to your java projects folder. On the project folder root, you will find build.gradle file for register dependencies, initially it looks like this.

plugins {

    id 'org.springframework.boot' version '2.1.6.RELEASE'

    id 'java'

    id 'war'

}

 

apply plugin: 'io.spring.dependency-management'

 

group = 'com.djamware'

version = '0.0.1-SNAPSHOT'

sourceCompatibility = '1.8'

 

repositories {

    mavenCentral()

}

 

dependencies {

    implementation 'org.springframework.boot:spring-boot-starter-data-mongodb-reactive'

    implementation 'org.springframework.boot:spring-boot-starter-security'

    implementation 'org.springframework.boot:spring-boot-starter-web'

    providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat'

    testImplementation 'org.springframework.boot:spring-boot-starter-test'

    testImplementation 'org.springframework.security:spring-security-test'

}

Now, you can work with the source code of this Spring Boot Project using your own IDE or Text Editor. We are using Visual Studio Code (VSCode). In the terminal or command line go to the extracted project folder then run the command to open VSCode.

cd spring-angular-auth 
code .

Next, we have to add the JWT library to the build.gradle as the dependency. Open and edit build.gradle then add this line to dependencies after other implementation.

implementation 'io.jsonwebtoken:jjwt:0.9.1'

Next, compile the Gradle Project by type this command from Terminal or CMD.

gradle compileJava

Next, open and edit src/main/resources/application.properties then add these lines.

spring.data.mongodb.database=springmongodb 
spring.data.mongodb.host=localhost 
spring.data.mongodb.port=27017

Create Product, User and Role Model or Entity Classes

We will be creating all required models or entities for products, user and role. Create a new folder and files inside that new folder.

mkdir src/main/java/com/djamware/springangularauth/models touch src/main/java/com/djamware/springangularauth/models/Products.java touch src/main/java/com/djamware/springangularauth/models/User.java touch src/main/java/com/djamware/springangularauth/models/Role.java

Next, open and edit src/main/java/com/djamware/springangularauth/models/Products.java then add these package and imports.

package com.djamware.springangularauth.models; 

import org.springframework.data.annotation.Id; 
import org.springframework.data.mongodb.core.mapping.Document;

Next, add these lines of codes for class, fields, document annotation that map to MongoDB collection, constructors, and getter/setter for each field.

@Document(collection = "products")
public class Products {
 
    @Id
    String id;
    String prodName;
    String prodDesc;
    Double prodPrice;
    String prodImage;
 
    public Products() {
    }
 
    public Products(String prodName, String prodDesc, Double prodPrice, String prodImage) {
        super();
        this.prodName = prodName;
        this.prodDesc = prodDesc;
        this.prodPrice = prodPrice;
        this.prodImage = prodImage;
    }
 
    public String getId() {
        return id;
    }
 
    public void setId(String id) {
        this.id = id;
    }
 
    public String getProdName() {
        return prodName;
    }
 
    public void setProdName(String prodName) {
        this.prodName = prodName;
    }
 
    public String getProdDesc() {
        return prodDesc;
    }
 
    public void setProdDesc(String prodDesc) {
        this.prodDesc = prodDesc;
    }
 
    public Double getProdPrice() {
        return prodPrice;
    }
 
    public void setProdPrice(Double prodPrice) {
        this.prodPrice = prodPrice;
    }
 
    public String getProdImage() {
        return prodImage;
    }
 
    public void setProdImage(String prodImage) {
        this.prodImage = prodImage;
    }
 
}

Next, open and edit src/main/java/com/djamware/springangularauth/models/User.java then add these package and imports.

package com.djamware.springangularauth.models;
 
import java.util.Set;
 
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.index.IndexDirection;
import org.springframework.data.mongodb.core.index.Indexed;
import org.springframework.data.mongodb.core.mapping.DBRef;
import org.springframework.data.mongodb.core.mapping.Document;

Add these lines of Java codes that contain document annotation that map to the MongoDB collection, class name, fields, constructors, and getter/setter of the fields.

@Document(collection = "users")
public class User {
 
    @Id
    private String id;
    @Indexed(unique = true, direction = IndexDirection.DESCENDING, dropDups = true)
    private String email;
    private String password;
    private String fullname;
    private boolean enabled;
    @DBRef
    private Set<Role> roles;
 
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getFullname() {
        return fullname;
    }
    public void setFullname(String fullname) {
        this.fullname = fullname;
    }
    public boolean isEnabled() {
        return enabled;
    }
    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }
    public Set<Role> getRoles() {
        return roles;
    }
    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }
 
}

Next, open and edit src/main/java/com/djamware/springangularauth/models/Role.java then add these package name and imports.

package com.djamware.springangularauth.models;
 
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.index.IndexDirection;
import org.springframework.data.mongodb.core.index.Indexed;
import org.springframework.data.mongodb.core.mapping.Document;

Add these lines of codes that contain document annotation that map to MongoDB collection, class name, fields/variables, constructors, and getter/setter for each field/variables.

@Document(collection = "users")
public class User {
 
    @Id
    private String id;
    @Indexed(unique = true, direction = IndexDirection.DESCENDING, dropDups = true)
    private String email;
    private String password;
    private String fullname;
    private boolean enabled;
    @DBRef
    private Set<Role> roles;
 
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getFullname() {
        return fullname;
    }
    public void setFullname(String fullname) {
        this.fullname = fullname;
    }
    public boolean isEnabled() {
        return enabled;
    }
    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }
    public Set<Role> getRoles() {
        return roles;
    }
    public void setRoles(Set<Role> roles) {
        this.roles = roles;
    }
 
}

If you want easier Java class creation, auto import organization, generate constructor, and generate getter/setter then you can use IDE like Eclipse, Netbeans, Spring Tool-Suite, or IntelliJ IDEA. So, you don't have to type all codes manually.

Create Product, User and Role Repository Interfaces

Next steps to create Product, User, and Role Repository Interfaces. Create a new folder and files for the repositories.

mkdir src/main/java/com/djamware/springangularauth/repositories
touch src/main/java/com/djamware/springangularauth/repositories/ProductRepository.java
touch src/main/java/com/djamware/springangularauth/repositories/UserRepository.java
touch src/main/java/com/djamware/springangularauth/repositories/RoleRepository.java

Next, open and edit src/main/java/com/djamware/springangularauth/repositories/ProductRepository.java then add these package name and imports.

package com.djamware.springangularauth.repositories;
 
import com.djamware.springangularauth.models.Products;
import org.springframework.data.mongodb.repository.MongoRepository;

Add these lines of codes that contain Java interface name that extends MongoRepository and deletes method.

public interface ProductRepository extends MongoRepository<Products, String> {
 
    @Override
    void delete(Products deleted);
}

Next, open and edit src/main/java/com/djamware/springangularauth/repositories/UserRepository.java then add these package name and imports.

package com.djamware.springangularauth.repositories; 

import com.djamware.springangularauth.models.User; 
import org.springframework.data.mongodb.repository.MongoRepository;

Add these lines of codes that contain Java interface name that extends MongoRepository and find by email method.

public interface UserRepository extends MongoRepository<User, String> {
 
    User findByEmail(String email);
}

Next, open and edit src/main/java/com/djamware/springangularauth/repositories/RoleRepository.java then add these package name and imports.

package com.djamware.springangularauth.repositories; 

import org.springframework.data.mongodb.repository.MongoRepository; 
import com.djamware.springangularauth.models.Role;

Add these lines of codes that contain Java interface name that extends MongoRepository and find by role method.

public interface RoleRepository extends MongoRepository<Role, String> {
 
    Role findByRole(String role);
}

Create a Custom User Details Service

To implements authentication using existing User and Role from MongoDB, we have to create a custom user details service. Create a new folder and Java file for the service.

mkdir src/main/java/com/djamware/springangularauth/services 
touch src/main/java/com/djamware/springangularauth/services/CustomUserDetailsService.java

Next, open and edit src/main/java/com/djamware/springangularauth/services/CustomUserDetailsService.java then add these package name and imports.

package com.djamware.springangularauth.services;
 
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.stereotype.Service;
 
import com.djamware.springangularauth.models.Role;
import com.djamware.springangularauth.models.User;
import com.djamware.springangularauth.repositories.RoleRepository;
import com.djamware.springangularauth.repositories.UserRepository;

Add these lines of codes that contains service annotation, the class name that implements UserDetailsService, required variables, constructors, and methods for the authentication process.

@Service
public class CustomUserDetailsService implements UserDetailsService {
 
    @Autowired
    private UserRepository userRepository;
 
    @Autowired
    private RoleRepository roleRepository;
 
    @Autowired
    private PasswordEncoder bCryptPasswordEncoder;
 
    public User findUserByEmail(String email) {
        return userRepository.findByEmail(email);
    }
 
    public void saveUser(User user) {
        user.setPassword(bCryptPasswordEncoder.encode(user.getPassword()));
        user.setEnabled(true);
        Role userRole = roleRepository.findByRole("ADMIN");
        user.setRoles(new HashSet<>(Arrays.asList(userRole)));
        userRepository.save(user);
    }
 
    @Override
    public UserDetails loadUserByUsername(String email) throws UsernameNotFoundException {
 
        User user = userRepository.findByEmail(email);
        if(user != null) {
            List<GrantedAuthority> authorities = getUserAuthority(user.getRoles());
            return buildUserForAuthentication(user, authorities);
        } else {
            throw new UsernameNotFoundException("username not found");
        }
    }
 
    private List<GrantedAuthority> getUserAuthority(Set<Role> userRoles) {
        Set<GrantedAuthority> roles = new HashSet<>();
        userRoles.forEach((role) -> {
            roles.add(new SimpleGrantedAuthority(role.getRole()));
        });
 
        List<GrantedAuthority> grantedAuthorities = new ArrayList<>(roles);
        return grantedAuthorities;
    }
 
    private UserDetails buildUserForAuthentication(User user, List<GrantedAuthority> authorities) {
        return new org.springframework.security.core.userdetails.User(user.getEmail(), user.getPassword(), authorities);
    }
}

Configure Spring Boot Security Rest

Now, the main purpose of this tutorial is configuring Spring Security Rest. First, we have to create a bean for JWT token generation and validation. Create a new folder and file for the configuration.

mkdir src/main/java/com/djamware/springangularauth/configs
touch src/main/java/com/djamware/springangularauth/configs/JwtTokenProvider.java
touch src/main/java/com/djamware/springangularauth/configs/JwtConfigurer.java
touch src/main/java/com/djamware/springangularauth/configs/JwtTokenFilter.java
touch src/main/java/com/djamware/springangularauth/configs/WebSecurityConfig.java

Next, open and edit src/main/java/com/djamware/springangularauth/configs/JwtTokenProvider.java then add these package name and imports.

package com.djamware.springangularauth.configs;
 
import java.util.Base64;
import java.util.Date;
import java.util.Set;
 
import javax.annotation.PostConstruct;
import javax.servlet.http.HttpServletRequest;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;
 
import com.djamware.springangularauth.models.Role;
import com.djamware.springangularauth.services.CustomUserDetailsService;
 
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jws;
import io.jsonwebtoken.JwtException;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

Next, add these lines of codes that contain component annotation, class name, variables, and methods.

@Component
public class JwtTokenProvider {
 
      @Value("${security.jwt.token.secret-key:secret}")
    private String secretKey = "secret";
 
    @Value("${security.jwt.token.expire-length:3600000}")
    private long validityInMilliseconds = 3600000; // 1h
 
    @Autowired
    private CustomUserDetailsService userDetailsService;
 
    @PostConstruct
    protected void init() {
        secretKey = Base64.getEncoder().encodeToString(secretKey.getBytes());
    }
 
    public String createToken(String username, Set<Role> set) {
        Claims claims = Jwts.claims().setSubject(username);
        claims.put("roles", set);
        Date now = new Date();
        Date validity = new Date(now.getTime() + validityInMilliseconds);
        return Jwts.builder()//
            .setClaims(claims)//
            .setIssuedAt(now)//
            .setExpiration(validity)//
            .signWith(SignatureAlgorithm.HS256, secretKey)//
            .compact();
    }
 
    public Authentication getAuthentication(String token) {
        UserDetails userDetails = this.userDetailsService.loadUserByUsername(getUsername(token));
        return new UsernamePasswordAuthenticationToken(userDetails, "", userDetails.getAuthorities());
    }
 
    public String getUsername(String token) {
        return Jwts.parser().setSigningKey(secretKey).parseClaimsJws(token).getBody().getSubject();
    }
 
    public String resolveToken(HttpServletRequest req) {
        String bearerToken = req.getHeader("Authorization");
        if (bearerToken != null && bearerToken.startsWith("Bearer ")) {
            return bearerToken.substring(7, bearerToken.length());
        }
        return null;
    }
 
    public boolean validateToken(String token) {
        try {
            Jws<Claims> claims = Jwts.parser().setSigningKey(secretKey).parseClaimsJws(token);
            if (claims.getBody().getExpiration().before(new Date())) {
                return false;
            }
            return true;
        } catch (JwtException | IllegalArgumentException e) {
            throw new JwtException("Expired or invalid JWT token");
        }
    }
}

Next, open and edit src/main/java/com/djamware/springangularauth/configs/JwtTokenFilter.java then add these package name and imports.

package com.djamware.springangularauth.configs;
 
import java.io.IOException;
 
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
 
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.web.filter.GenericFilterBean;

Next, add these lines of codes that contain component annotation, class name, variables, and methods.

public class JwtTokenFilter extends GenericFilterBean {
 
    private JwtTokenProvider jwtTokenProvider;
 
    public JwtTokenFilter(JwtTokenProvider jwtTokenProvider) {
        this.jwtTokenProvider = jwtTokenProvider;
    }
 
    @Override
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain)
        throws IOException, ServletException {
        String token = jwtTokenProvider.resolveToken((HttpServletRequest) req);
        if (token != null && jwtTokenProvider.validateToken(token)) {
            Authentication auth = token != null ? jwtTokenProvider.getAuthentication(token) : null;
            SecurityContextHolder.getContext().setAuthentication(auth);
        }
        filterChain.doFilter(req, res);
    }
}

Next, open and edit src/main/java/com/djamware/springangularauth/configs/JwtConfigurer.java then add these package name and imports.

package com.djamware.springangularauth.configs;
 
import org.springframework.security.config.annotation.SecurityConfigurerAdapter;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.web.DefaultSecurityFilterChain;
import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;

Next, add these lines of codes that contain component annotation, the class name that extends the SecurityConfigurerAdapter, variables, and methods.

public class JwtConfigurer extends SecurityConfigurerAdapter<DefaultSecurityFilterChain, HttpSecurity> {
 
    private JwtTokenProvider jwtTokenProvider;
 
    public JwtConfigurer(JwtTokenProvider jwtTokenProvider) {
        this.jwtTokenProvider = jwtTokenProvider;
    }
 
    @Override
    public void configure(HttpSecurity http) throws Exception {
        JwtTokenFilter customFilter = new JwtTokenFilter(jwtTokenProvider);
        http.addFilterBefore(customFilter, UsernamePasswordAuthenticationFilter.class);
    }
}

Finally, we have to configure the Spring Security by open and edit src/main/java/com/djamware/springangularauth/configs/WebSecurityConfig.java then add these package name and imports.

package com.djamware.springangularauth.configs;
 
import javax.servlet.http.HttpServletResponse;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationManager;
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.builders.WebSecurity;
import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
import org.springframework.security.config.http.SessionCreationPolicy;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.security.crypto.password.PasswordEncoder;
import org.springframework.security.web.AuthenticationEntryPoint;
 
import com.djamware.springangularauth.services.CustomUserDetailsService;

Add these lines of codes that contains Configuration and EnableWebSecurity annotation, class name that extends WebSecurityConfigurerAdapter, required variables, constructors, and methods.

@Configuration
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {
 
    @Autowired
    JwtTokenProvider jwtTokenProvider;
 
    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        UserDetailsService userDetailsService = mongoUserDetails();
        auth.userDetailsService(userDetailsService).passwordEncoder(bCryptPasswordEncoder());
 
    }
 
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.httpBasic().disable().csrf().disable().sessionManagement()
                .sessionCreationPolicy(SessionCreationPolicy.STATELESS).and().authorizeRequests()
                .antMatchers("/api/auth/login").permitAll().antMatchers("/api/auth/register").permitAll()
                .antMatchers("/api/products/**").hasAuthority("ADMIN").anyRequest().authenticated().and().csrf()
                .disable().exceptionHandling().authenticationEntryPoint(unauthorizedEntryPoint()).and()
                .apply(new JwtConfigurer(jwtTokenProvider));
    http.cors();
    }
 
    @Override
    public void configure(WebSecurity web) throws Exception {
        web.ignoring().antMatchers("/resources/**", "/static/**", "/css/**", "/js/**", "/images/**");
    }
 
    @Bean
    public PasswordEncoder bCryptPasswordEncoder() {
        return new BCryptPasswordEncoder();
    }
 
    @Bean
    @Override
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }
 
    @Bean
    public AuthenticationEntryPoint unauthorizedEntryPoint() {
        return (request, response, authException) -> response.sendError(HttpServletResponse.SC_UNAUTHORIZED,
                "Unauthorized");
    }
 
    @Bean
    public UserDetailsService mongoUserDetails() {
        return new CustomUserDetailsService();
    }
}

Create Product and Authentication Controllers

Now it's time for REST API endpoint. All RESTful API will be created from each controller. Product controller will handle CRUD endpoint of product and Authentication controller will handle login and register endpoint. Create a new folder and files for the controllers.

mkdir src/main/java/com/djamware/springangularauth/controllers
touch src/main/java/com/djamware/springangularauth/controllers/ProductController.java
touch src/main/java/com/djamware/springangularauth/controllers/AuthController.java
touch src/main/java/com/djamware/springangularauth/controllers/AuthBody.java

Next, open and edit src/main/java/com/djamware/springangularauth/controllers/AuthController.java then add these package name and imports.

package com.djamware.springangularauth.controllers;
 
import java.util.Optional;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
 
import com.djamware.springangularauth.models.Products;
import com.djamware.springangularauth.repositories.ProductRepository;

Add these lines of codes that contain RestController annotation, class name, required variables, constructors, and methods.

@CrossOrigin(origins = "*")
@RequestMapping("/api")
@RestController
public class ProductController {
 
    @Autowired
    ProductRepository productRepository;
 
    @RequestMapping(method = RequestMethod.GET, value = "/products")
    public Iterable<Products> product() {
        return productRepository.findAll();
    }
}

Next, open and edit src/main/java/com/djamware/springangularauth/controllers/AuthController.java then add these package name and imports.

package com.djamware.springangularauth.controllers;
 
import static org.springframework.http.ResponseEntity.ok;
 
import java.util.HashMap;
import java.util.Map;
 
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.AuthenticationException;
import org.springframework.web.bind.annotation.CrossOrigin;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
 
import com.djamware.springangularauth.configs.JwtTokenProvider;
import com.djamware.springangularauth.models.User;
import com.djamware.springangularauth.repositories.UserRepository;
import com.djamware.springangularauth.services.CustomUserDetailsService;

Add these lines of codes that contain RestController and RequestMapping annotation, class name, required variables, constructors, and methods.

@CrossOrigin(origins = "*")
@RestController
@RequestMapping("/api/auth")
public class AuthController {
 
    @Autowired
    AuthenticationManager authenticationManager;
 
    @Autowired
    JwtTokenProvider jwtTokenProvider;
 
    @Autowired
    UserRepository users;
 
    @Autowired
    private CustomUserDetailsService userService;
 
    @SuppressWarnings("rawtypes")
    @PostMapping("/login")
    public ResponseEntity login(@RequestBody AuthBody data) {
        try {
            String username = data.getEmail();
            authenticationManager.authenticate(new UsernamePasswordAuthenticationToken(username, data.getPassword()));
            String token = jwtTokenProvider.createToken(username, this.users.findByEmail(username).getRoles());
            Map<Object, Object> model = new HashMap<>();
            model.put("username", username);
            model.put("token", token);
            return ok(model);
        } catch (AuthenticationException e) {
            throw new BadCredentialsException("Invalid email/password supplied");
        }
    }
 
    @SuppressWarnings("rawtypes")
    @PostMapping("/register")
    public ResponseEntity register(@RequestBody User user) {
        User userExists = userService.findUserByEmail(user.getEmail());
        if (userExists != null) {
            throw new BadCredentialsException("User with username: " + user.getEmail() + " already exists");
        }
        userService.saveUser(user);
        Map<Object, Object> model = new HashMap<>();
        model.put("message", "User registered successfully");
        return ok(model);
    }
}

Next, open and edit src/main/java/com/djamware/springangularauth/controllers/AuthBody.java then add these package name.

package com.djamware.springangularauth.controllers;

Add these lines of codes that contains the class name, fields or variables, and getter/setter for those variables.

public class AuthBody {
 
    private String email;
    private String password;
 
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
 
}

Install or Update Angular 8 CLI and Create Application

Before installing the Angular 8 CLI, make sure you have installed Node.js https://nodejs.org and can open Node.js command prompt. Next, open the Node.js command prompt then type this command to install

Angular 8 CLI.

sudo npm install -g @angular/cli

Next, create an Angular 8 application by typing this command in the root of the Spring Boot application/project directory.

ng new client

Where client is the name of the Angular 8 application. You can specify your own name, we like to name it client because it's put inside Spring Boot Project directory. If there's a question, we fill them with Y and SCSS. Next, go to the newly created Angular 8 application.

cd client

Run the Angular 8 application for the first time.

ng serve

Now, go to localhost:4200 and you should see this page.

Add Routes for Navigation between Angular 8 Pages/Component

On the previous steps, we have to add Angular 8 Routes when answering the questions. Now, we just added the required pages for CRUD (Create, Read, Update, Delete) Supplier data. Type this commands to add the Angular 8 components or pages.

ng g component products
ng g component auth/login
ng g component auth/register

Open src/app/app.module.ts then you will see those components imported and declared in @NgModule declarations. Next, open and edit src/app/app-routing.module.ts then add these imports.

import { ProductsComponent } from './products/products.component';
import { LoginComponent } from './auth/login/login.component';
import { RegisterComponent } from './auth/register/register.component';

Add these arrays to the existing routes constant.

const routes: Routes = [
  {
    path: '',
    redirectTo: 'products',
    pathMatch: 'full'
  },
  {
    path: 'products',
    component: ProductsComponent,
    data: { title: 'List of Products' }
  },
  {
    path: 'login',
    component: LoginComponent,
    data: { title: 'Login' }
  },
  {
    path: 'register',
    component: RegisterComponent,
    data: { title: 'Register' }
  }
];

Open and edit src/app/app.component.html and you will see the existing router outlet. Next, modify this HTML page to fit the CRUD page.

<div class="container">
  <router-outlet></router-outlet>
</div>

Open and edit src/app/app.component.scss then replace all SCSS codes with this.

.container {
  padding: 20px;
}

Create a custom Angular 8 HttpInterceptor

Before creating a custom Angular 8 HttpInterceptor, create a folder with the name client/src/app/interceptors. Next, create a file for the custom Angular 8 HttpInterceptor with the name client/src/app/interceptors/token.interceptor.ts. Open and edit that file the add these imports.

import { Injectable } from '@angular/core';
import {
    HttpRequest,
    HttpHandler,
    HttpEvent,
    HttpInterceptor,
    HttpResponse,
    HttpErrorResponse
} from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { map, catchError } from 'rxjs/operators';
import { Router } from '@angular/router';

Create a class that implementing HttpInterceptor method.

@Injectable()
export class TokenInterceptor implements HttpInterceptor {
 
}

Inject the required module to the constructor inside the class.

constructor(private router: Router) {}

Implement a custom Interceptor function.

intercept(request: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {
 
    const token = localStorage.getItem('token');
    if (token) {
      request = request.clone({
        setHeaders: {
          'Authorization': 'Bearer ' + token
        }
      });
    }
    if (!request.headers.has('Content-Type')) {
      request = request.clone({
        setHeaders: {
          'content-type': 'application/json'
        }
      });
    }
    request = request.clone({
      headers: request.headers.set('Accept', 'application/json')
    });
    return next.handle(request).pipe(
      map((event: HttpEvent<any>) => {
        if (event instanceof HttpResponse) {
          console.log('event--->>>', event);
        }
        return event;
      }),
      catchError((error: HttpErrorResponse) => {
        console.log(error);
        if (error.status === 401) {
          this.router.navigate(['login']);
        }
        if (error.status === 400) {
          alert(error.error);
        }
        return throwError(error);
      }));
}

Next, we have to register this custom HttpInterceptor and HttpClientModule. Open and edit client/src/app.module.ts then add these imports.

import { HTTP_INTERCEPTORS, HttpClientModule } from '@angular/common/http'; 
import { TokenInterceptor } from './interceptors/token.interceptor';

Add HttpClientModule to the @NgModule imports array.

imports: [
  BrowserModule,
  AppRoutingModule,
  HttpClientModule
],

Add the Interceptor modules to the provider array of the @NgModule.

providers: [
  {
    provide: HTTP_INTERCEPTORS,
    useClass: TokenInterceptor,
    multi: true
  }
],

Now, the HTTP interceptor is ready to intercept any request to the API.

Create Services for Accessing Product and Authentication API

To access the Spring Boot RESTful API from Angular 8 application, we have to create services for that. Type these commands to generate the Angular 8 services from the client folder.

ng g service auth 
ng g service product

Next, open and edit client/src/app/auth.service.ts then add these imports.

import { HttpClient } from '@angular/common/http'; 
import { Observable, of } from 'rxjs'; 
import { catchError, tap } from 'rxjs/operators';

Declare a constant variable as Spring Boot RESTful API URL after the imports.

const apiUrl = 'http://192.168.0.7:8080/api/auth/';

Declare the variables before the constructor that will use by Angular 8 Route Guard.

isLoggedIn = false; 
redirectUrl: string;

Inject the HttpClient module inside the constructor.

constructor(private http: HttpClient) { }

Create all required functions for Login, Logout, Register, and helper functions.

login(data: any): Observable<any> {
  return this.http.post<any>(apiUrl + 'login', data)
    .pipe(
      tap(_ => this.isLoggedIn = true),
      catchError(this.handleError('login', []))
    );
}
 
logout(): Observable<any> {
  return this.http.get<any>(apiUrl + 'signout')
    .pipe(
      tap(_ => this.isLoggedIn = false),
      catchError(this.handleError('logout', []))
    );
}
 
register(data: any): Observable<any> {
  return this.http.post<any>(apiUrl + 'register', data)
    .pipe(
      tap(_ => this.log('login')),
      catchError(this.handleError('login', []))
    );
}
 
private handleError<T>(operation = 'operation', result?: T) {
  return (error: any): Observable<T> => {
 
    console.error(error); // log to console instead
    this.log(`${operation} failed: ${error.message}`);
 
    return of(result as T);
  };
}
 
private log(message: string) {
  console.log(message);
}

Next, create an object class that represents Product data client/src/app/products/product.ts then replace all file contents with these.

export class Product {
    productId: number;
    isbn: string;
    title: string;
    author: string;
    description: string;
    publisher: string;
    publishedYear: number;
    price: number;
}

Next, open and edit client/src/app/services/product.service.ts then replace all codes with this.

import { Injectable } from '@angular/core';
import { Product } from './products/product';
import { HttpClient } from '@angular/common/http';
import { Observable, of } from 'rxjs';
import { catchError, tap } from 'rxjs/operators';
 
const apiUrl = 'http://192.168.0.7:8080/api/products';
 
@Injectable({
  providedIn: 'root'
})
export class ProductService {
 
  constructor(private http: HttpClient) { }
 
  getProducts(): Observable<Product[]> {
    return this.http.get<Product[]>(apiUrl + 'Product')
      .pipe(
        tap(_ => this.log('fetched Products')),
        catchError(this.handleError('getProducts', []))
      );
  }
 
  private handleError<T>(operation = 'operation', result?: T) {
    return (error: any): Observable<T> => {
 
      console.error(error); // log to console instead
      this.log(`${operation} failed: ${error.message}`);
 
      return of(result as T);
    };
  }
 
  private log(message: string) {
    console.log(message);
  }
}

Display List of Product using Angular 8 Material

To display a list of products to the Angular 8 template. First, open and edit client/src/app/products/products.component.ts then add these imports.

import { Product } from './product'; 
import { ProductService } from '../product.service'; 
import { AuthService } from '../auth.service'; 
import { Router } from '@angular/router';

Next, inject the Product and Auth Services to the constructor.

constructor(private productService: ProductService, private authService: AuthService, private router: Router) { }

Declare these variables before the constructor.

data: Product[] = [];
displayedColumns: string[] = ['prodName', 'prodDesc', 'prodPrice'];
isLoadingResults = true;

Create a function for consuming or get a product list from the producing service.

getProducts(): void {
  this.productService.getProducts()
    .subscribe(products => {
      this.data = products;
      console.log(this.data);
      this.isLoadingResults = false;
    }, err => {
      console.log(err);
      this.isLoadingResults = false;
    });
}

Call this function from ngOnInit.

ngOnInit() {
  this.getProducts();
}

Add a function for log out the current session.

logout() {
  localStorage.removeItem('token');
  this.router.navigate(['login']);
}

Next, for the user interface (UI) we will use Angular 8 Material and CDK. There's a CLI for generating a Material component like Table as a component, but we will create or add the Table component from scratch to existing component. Type this command to install Angular 8 Material.

ng add @angular/material

If there are some questions, answer them like below.

? Choose a prebuilt theme name, or "custom" for a custom theme: Purple/Green       [ Preview: https://material.angular.i
o?theme=purple-green ]
? Set up HammerJS for gesture recognition? Yes
? Set up browser animations for Angular Material? Yes

Next, we have to register all required Angular Material components or modules to src/app/app.module.ts. Open and edit that file then add this imports.

import {
  MatInputModule,
  MatPaginatorModule,
  MatProgressSpinnerModule,
  MatSortModule,
  MatTableModule,
  MatIconModule,
  MatButtonModule,
  MatCardModule,
  MatFormFieldModule } from '@angular/material';

Also, add FormsModule and ReactiveFormsModule.

import { FormsModule, ReactiveFormsModule } from '@angular/forms';

Register the above modules to @NgModule imports.

imports: [
  BrowserModule,
  FormsModule,
  HttpClientModule,
  AppRoutingModule,
  ReactiveFormsModule,
  BrowserAnimationsModule,
  MatInputModule,
  MatTableModule,
  MatPaginatorModule,
  MatSortModule,
  MatProgressSpinnerModule,
  MatIconModule,
  MatButtonModule,
  MatCardModule,
  MatFormFieldModule
],

Next, open and edit client/src/app/products/products.component.html then replace all HTML tags with this Angular 8 Material tags.

<div class="example-container mat-elevation-z8">
  <div class="example-loading-shade"
       *ngIf="isLoadingResults">
    <mat-spinner *ngIf="isLoadingResults"></mat-spinner>
  </div>
  <div class="button-row">
    <a mat-flat-button color="primary" (click)="logout()">Logout</a>
  </div>
  <div class="mat-elevation-z8">
    <table mat-table [dataSource]="data" class="example-table">
 
      <!-- Product ID Column -->
      <ng-container matColumnDef="prodName">
        <th mat-header-cell *matHeaderCellDef>Product Name</th>
        <td mat-cell *matCellDef="let row">{{row.prodName}}</td>
      </ng-container>
 
      <!-- ISBN Column -->
      <ng-container matColumnDef="prodDesc">
        <th mat-header-cell *matHeaderCellDef>Product Description</th>
        <td mat-cell *matCellDef="let row">{{row.prodDesc}}</td>
      </ng-container>
 
      <!-- Title Column -->
      <ng-container matColumnDef="prodPrice">
        <th mat-header-cell *matHeaderCellDef>Product Price</th>
        <td mat-cell *matCellDef="let row">{{row.prodPrice}}</td>
      </ng-container>
 
      <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
      <tr mat-row *matRowDef="let row; columns: displayedColumns;"></tr>
    </table>
  </div>
</div>

Finally, we have to align the style for this page. Open and edit client/src/app/products/products.component.scss then replace all SCSS codes with these.

/* Structure */
.example-container {
    position: relative;
    padding: 5px;
}
 
.example-table-container {
    position: relative;
    max-height: 400px;
    overflow: auto;
}
 
table {
    width: 100%;
}
 
.example-loading-shade {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 56px;
    right: 0;
    background: rgba(0, 0, 0, 0.15);
    z-index: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}
 
.example-rate-limit-reached {
    color: #980000;
    max-width: 360px;
    text-align: center;
}
 
/* Column Widths */
.mat-column-number,
.mat-column-state {
    max-width: 64px;
}
 
.mat-column-created {
    max-width: 124px;
}
 
.mat-flat-button {
    margin: 5px;
}

Create the Angular 8 Login and Register Page

This time for authentication part. Open and edit client/src/app/auth/login/login.component.ts then add these imports.

import { FormControl, FormGroupDirective, FormBuilder, FormGroup, NgForm, Validators } from '@angular/forms';
import { AuthService } from '../../auth.service';
import { Router } from '@angular/router';
import { ErrorStateMatcher } from '@angular/material/core';

Declare these variables before the constructor.

loginForm: FormGroup;
email = '';
password = '';
matcher = new MyErrorStateMatcher();
isLoadingResults = false;

Inject the imported modules to the constructor.

constructor(private formBuilder: FormBuilder, private router: Router, private authService: AuthService) { }

Initialize NgForm to the NgOnInit function.

ngOnInit() {
  this.loginForm = this.formBuilder.group({
    'email' : [null, Validators.required],
    'password' : [null, Validators.required]
  });
}

Add a function to submit the login form.

onFormSubmit(form: NgForm) {
  this.authService.login(form)
    .subscribe(res => {
      console.log(res);
      if (res.token) {
        localStorage.setItem('token', res.token);
        this.router.navigate(['products']);
      }
    }, (err) => {
      console.log(err);
    });
}

Add a function to go to the Register page.

register() {
  this.router.navigate(['register']);
}

Add a class that handles the form validation above this class.

/** Error when invalid control is dirty, touched, or submitted. */
export class MyErrorStateMatcher implements ErrorStateMatcher {
  isErrorState(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean {
    const isSubmitted = form && form.submitted;
    return !!(control && control.invalid && (control.dirty || control.touched || isSubmitted));
  }
}

Next, open and edit client/src/app/auth/login/login.component.html then replace all HTML tags with these.

<div class="example-container mat-elevation-z8">
  <div class="example-loading-shade"
       *ngIf="isLoadingResults">
    <mat-spinner *ngIf="isLoadingResults"></mat-spinner>
  </div>
  <mat-card class="example-card">
    <form [formGroup]="loginForm" (ngSubmit)="onFormSubmit(loginForm.value)">
      <mat-form-field class="example-full-width">
        <input matInput type="email" placeholder="Email" formControlName="email"
               [errorStateMatcher]="matcher">
        <mat-error>
          <span *ngIf="!loginForm.get('email').valid && loginForm.get('email').touched">Please enter your email</span>
        </mat-error>
      </mat-form-field>
      <mat-form-field class="example-full-width">
        <input matInput type="password" placeholder="Password" formControlName="password"
               [errorStateMatcher]="matcher">
        <mat-error>
          <span *ngIf="!loginForm.get('password').valid && loginForm.get('password').touched">Please enter your password</span>
        </mat-error>
      </mat-form-field>
      <div class="button-row">
        <button type="submit" [disabled]="!loginForm.valid" mat-flat-button color="primary">Login</button>
      </div>
      <div class="button-row">
        <button type="button" mat-flat-button color="primary" (click)="register()">Register</button>
      </div>
    </form>
  </mat-card>
</div>

Next, give this page a style by open and edit client/src/app/auth/login/login.component.scss then applies these styles codes.

/* Structure */
.example-container {
  position: relative;
  padding: 5px;
}
 
.example-form {
  min-width: 150px;
  max-width: 500px;
  width: 100%;
}
 
.example-full-width {
  width: 100%;
}
 
.example-full-width:nth-last-child() {
  margin-bottom: 10px;
}
 
.button-row {
  margin: 10px 0;
}
 
.mat-flat-button {
  margin: 5px;
}

Next, for register page, open and edit client/src/app/auth/register/register.component.ts then replace all Typescript codes with these.

import { Component, OnInit } from '@angular/core';
import { FormControl, FormGroupDirective, FormBuilder, FormGroup, NgForm, Validators } from '@angular/forms';
import { AuthService } from '../../auth.service';
import { Router } from '@angular/router';
import { ErrorStateMatcher } from '@angular/material/core';
 
@Component({
  selector: 'app-register',
  templateUrl: './register.component.html',
  styleUrls: ['./register.component.scss']
})
export class RegisterComponent implements OnInit {
 
  registerForm: FormGroup;
  fullName = '';
  email = '';
  password = '';
  isLoadingResults = false;
  matcher = new MyErrorStateMatcher();
 
  constructor(private formBuilder: FormBuilder, private router: Router, private authService: AuthService) { }
 
  ngOnInit() {
    this.registerForm = this.formBuilder.group({
      'fullName' : [null, Validators.required],
      'email' : [null, Validators.required],
      'password' : [null, Validators.required]
    });
  }
 
  onFormSubmit(form: NgForm) {
    this.authService.register(form)
      .subscribe(res => {
        this.router.navigate(['login']);
      }, (err) => {
        console.log(err);
        alert(err.error);
      });
  }
 
}
 
/** Error when invalid control is dirty, touched, or submitted. */
export class MyErrorStateMatcher implements ErrorStateMatcher {
  isErrorState(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean {
    const isSubmitted = form && form.submitted;
    return !!(control && control.invalid && (control.dirty || control.touched || isSubmitted));
  }
}

Next, open and edit client/src/app/auth/register/register.component.html then replace all HTML tags with these.

<div class="example-container mat-elevation-z8">
  <div class="example-loading-shade"
       *ngIf="isLoadingResults">
    <mat-spinner *ngIf="isLoadingResults"></mat-spinner>
  </div>
  <mat-card class="example-card">
    <form [formGroup]="registerForm" (ngSubmit)="onFormSubmit(registerForm.value)">
      <mat-form-field class="example-full-width">
        <input matInput type="fullName" placeholder="Full Name" formControlName="fullName"
                [errorStateMatcher]="matcher">
        <mat-error>
          <span *ngIf="!registerForm.get('fullName').valid && registerForm.get('fullName').touched">Please enter your Full Name</span>
        </mat-error>
      </mat-form-field>
      <mat-form-field class="example-full-width">
        <input matInput type="email" placeholder="Email" formControlName="email"
               [errorStateMatcher]="matcher">
        <mat-error>
          <span *ngIf="!registerForm.get('email').valid && registerForm.get('email').touched">Please enter your email</span>
        </mat-error>
      </mat-form-field>
      <mat-form-field class="example-full-width">
        <input matInput type="password" placeholder="Password" formControlName="password"
               [errorStateMatcher]="matcher">
        <mat-error>
          <span *ngIf="!registerForm.get('password').valid && registerForm.get('password').touched">Please enter your password</span>
        </mat-error>
      </mat-form-field>
      <div class="button-row">
        <button type="submit" [disabled]="!registerForm.valid" mat-flat-button color="primary">Register</button>
      </div>
    </form>
  </mat-card>
</div>

Finally, open and edit client/src/app/auth/register/register.component.scss then replace all SCSS codes with these.

/* Structure */
.example-container {
  position: relative;
  padding: 5px;
}
 
.example-form {
  min-width: 150px;
  max-width: 500px;
  width: 100%;
}
 
.example-full-width {
  width: 100%;
}
 
.example-full-width:nth-last-child() {
  margin-bottom: 10px;
}
 
.button-row {
  margin: 10px 0;
}
 
.mat-flat-button {
  margin: 5px;
}

Secure the Guarded Products Page using Angular 8 Route Guard

As we mention in the beginning that the Angular 8 application will use Angular 8 Route Guard to secure the products page. So, we have both securities for the Angular 8 page and for Spring Boot RESTful API. Type this command to generate a guard configuration file.

ng generate guard auth/auth

Open and edit that file then add this Angular 8 or Typescript imports.

import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, Router } from '@angular/router';
import { Observable } from 'rxjs';
import { AuthService } from '../auth.service';

Next, add this implements code to the Class name.

export class AuthGuard implements CanActivate

Inject the AuthService and the Router to the constructor params.

constructor(private authService: AuthService, private router: Router) {}

Add the function for the Route Guard.

canActivate(
  next: ActivatedRouteSnapshot,
  state: RouterStateSnapshot): boolean {
  const url: string = state.url;
 
  return this.checkLogin(url);
}

Add the function to check the login status and redirect to the login page if it's not logged in and redirect to the Guarded page if it's logged in.

checkLogin(url: string): boolean {
  if (this.authService.isLoggedIn) { return true; }
 
  // Store the attempted URL for redirecting
  this.authService.redirectUrl = url;
 
  // Navigate to the login page with extras
  this.router.navigate(['/login']);
  return false;
}

Next, open and edit src/app/app-routing.module.ts then add this import.

import { AuthGuard } from './auth/auth.guard';

Modify the product path, so it will look like this.

const routes: Routes = [
  {
    path: 'products',
    canActivate: [AuthGuard],
    component: ProductsComponent,
    data: { title: 'List of Products' }
  },
  {
    path: 'login',
    component: LoginComponent,
    data: { title: 'Login' }
  },
  {
    path: 'register',
    component: RegisterComponent,
    data: { title: 'Register' }
  }
];

Run and Test The Authentication of The Spring Boot, Security, MongoDB, and Angular 8 Web Application

Before run the Spring Boot RESTful API, make sure the MongoDB server is running by type this command in another terminal or command line tab.

mongod

In the different tab run the Spring Boot RESTful API using this command.

gradle bootRun

Open again a new terminal tab then go to the client folder then run the Angular 8 application.

ng serve

Next, open the browser then go to [http://localhost:4200](http://localhost:4200 "http://localhost:4200") and you

should see then login page because of the landing page that point to

products page will redirect to login if not logged in.

That it's the Spring Boot, Security, MongoDB, Angular 8: Build Authentication. You can find the full source code from our GitHub.

Build a Reactive App with Spring Boot and MongoDB

Build a Reactive App with Spring Boot and MongoDB

This tutorial shows how to build a non-blocking, reactive app with Spring Boot, Spring WebFlux, and MongoDB


Reactive apps allow you to scale better if you’re dealing with lots of streaming data. They’re non-blocking and tend to be more efficient because they’re not tying up processing while waiting for stuff to happen.

Reactive systems embrace asynchronous I/O. The concept behind asynchronous I/O is straightforward: alleviate inefficient resource utilization by reclaiming resources that would otherwise be idle as they waited for I/O activity. Asynchronous I/O inverts the normal design of I/O processing: the clients are notified of new data instead of asking for it; this frees the client to do other things while waiting.

If you’re going to build a reactive app, you’ll need it to be reactive all the way down to your database. Use a blocking JDBC driver with Spring WebFlux, and you’ll be disappointed in its performance. Use a reactive NoSQL database like Cassandra, MongoDB, Couchbase and Redis – and you’ll be impressed by its performance.

In this tutorial, you’ll learn how to use Spring Boot, Spring WebFlux, and Spring Data to create a reactive web service that talks to a NoSQL database backend (MongoDB, in this case).

I just threw a handful of terms at you. Let’s go over them.

If you already understand NoSQL and Reactive programming and just want to see some code, feel free to skip the first two sections and start with “Build a Spring Boot Resource Server”.


What is NoSQL and Why MongoDB?

NoSQL is a term for any non-relational database. In relational databases (think SQL, MySQL, etc…), data is stored in tables with strong typing and well-defined relationships between table columns. The tight, well-defined structure of relational databases is both their strength and their weakness. It’s a trade-off. NoSQL databases explode this model and provide other models that allow for more flexibility and ease of scaling.

The microservice/cluster model of scaling created lots of problems for relational databases. They just weren’t built to run and stay in sync across multiple machines. NoSQL databases were developed, in part, to address this problem. Often, they were built with clustering and horizontal scaling in mind. To present this another way, classically with SQL databases, if you needed more power, you had to resize the server that the database was running on; it was pretty monolithic, and this is hard to do dynamically, even with all the modern virtual server snazziness available these days. At internet scale, a far better model is to have a flexible cluster of databases that automatically sync between them and that allow you to spin up instances as demand requires (and spin them down when demand lessens). This means that adding more power doesn’t require ever more expensive machines; you can simply add more, relatively cheap machines as needed.

Another potential benefit of NoSQL databases is their flexibility. A document-based NoSQL database like MongoDB can store arbitrary data in documents. Fields can be added to the stored documents on the fly, without the overhead of table migrations and what not. Of course, this doesn’t solve the problem of versioning and it’s still up to the app to deal with the changing data structure (not always trivial), but at least you’re not fighting the database.

All that said, keep in mind that SQL/relational databases aren’t going anywhere. They’re proven, fast, and super reliable. In some use cases, they’re cheaper and easier. MySQL is hard to beat for a simple website or blog, for example. But even in an enterprise setting, sometimes you want the structure that a relational database enforces. If you have a fairly static data model and don’t need to scale to internet scale, SQL may be the best choice. These types of design considerations are worth pondering before you dive into a database choice simply because it’s new and flashy.

I’m using MongoDB in this tutorial because it’s a breeze to start with. If you use Spring Data MongoDB, it’s even easier!


Get Reactive!

Reactive is another great bit of jargon. It feels like the kind of word that people like to throw around at parties and conferences with only vague ideas of what it actually means. Like “existential” or “ennui.” Let’s define it.

If you take a look at the Spring WebFlux documentation, they give a pretty good overview of what reactive means.

The term, “reactive,” refers to programming models that are built around reacting to change — network components reacting to I/O events, UI controllers reacting to mouse events, and others. In that sense, non-blocking is reactive, because, instead of being blocked, we are now in the mode of reacting to notifications as operations complete or data becomes available.

So reactive means: non-blocking, asynchronous, and centered around stream processing.


Build a Spring Boot Resource Server

Clone the starter project from the GitHub repository and check out the start branch:

git clone -b start https://github.com/oktadeveloper/okta-spring-boot-mongo-webflux-example.git

The starter project is a simple Spring Boot starter project with the necessary dependencies already in the build.gradle file.

Let’s take a quick look at the dependencies:

compile('org.springframework.boot:spring-boot-starter-webflux')
compile('org.springframework.boot:spring-boot-starter-data-mongodb-reactive')
compileOnly('org.projectlombok:lombok')
compile('de.flapdoodle.embed:de.flapdoodle.embed.mongo')

The first is for Spring WebFlux, the reactive version of Spring MVC. The second brings in the reactive MongoDB dependencies that Spring needs. The third is a project called Lombok that saves us from typing a bunch of constructors, getters, and setters in our Java code (you can check out the project on their webpage). The last dependency is an embedded, in-memory MongoDB database. This database is great for testing, simple tutorials like this, and isn’t persisted.

The application can be run using a simple Gradle command:

./gradlew bootRun

Of course, if you run the app at this point it’s not going to do much. Spring Boot will load, but there aren’t any controllers, resources, or repositories defined yet, so nothing much happens.


Define a Model Class for MongoDB

For clarity, this tutorial is going to parallel the first part of this series that I mentioned earlier. You’re going to build a simple server that stores types of kayaks. I always suggest starting any project by defining the data structure first.

Create a Kayak.java class file in the com.okta.springbootmongo package:

package com.okta.springbootmongo;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.mongodb.core.mapping.Document;

@Document
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Kayak {
private String name;
private String owner;
private Number value;
private String makeModel;
}

The @Document annotation is the NoSQL equivalent of @Entity. It tells Spring Boot that this class is defining a data model. In the NoSQL world, this means creating a document instead of a table entry. The other three annotations are Lombok helpers that autogenerate getters, setters, and constructors.

The kayak document has five properties: name, owner, value, and type. These are automatically mapped to appropriate BSON types for MongoDB. What’s a BSON type? Take a look at the MongoDB docs on the subject. They are the binary serialization types used to persist data in MongoDB documents. They define the primitive types that can be stored in a MongoDB database.


Add a ReactiveMongoRepository to Your Spring Boot App

Defining the Kayak class with the @Document annotation tells Spring Boot about the structure of the data, but doesn’t actually give us any way of saving or loading data from the database. In order to do that, you need to define a Repository.

The code for that is beguilingly simple. Create a KayakRepository.java class file in the com.okta.springbootmongo package:

package com.okta.springbootmongo;

import org.springframework.data.mongodb.repository.ReactiveMongoRepository;

public interface KayakRepository extends ReactiveMongoRepository<Kayak, Long> {
}

This actually gives you all of the basic methods you need to create, update, read, and delete documents from the database. To understand how, dig into the ReactiveMongoRepository class and the various other superclasses, particularly ReactiveCrudRepository. Take a look at the docs for ReactiveCrudRepository to see the implemented methods.

ReactiveCrudRepository actually provides a basic and complete set of CRUD methods. ReactiveMongoRepository builds on top of that to provide some MongoDB-specific querying features.


Implement a Controller with Spring WebFlux

With the repository added, you have enough to manipulate the data programmatically. However, there are no web endpoints defined. In the previous tutorial, to add REST endpoints, all that was required was to add the @RepositoryRestResource annotation to the KayakRepository class. This autogenerated a fully functioning REST resource for us with all of the CRUD methods. This shortcut does not work with Spring WebFlux, however. Any public web endpoints will have to be explicitly defined.

Add the following KayakController.java class

package com.okta.springbootmongo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import reactor.core.publisher.Flux;

@Controller
@RequestMapping(path = "/kayaks")
public class KayakController {

private KayakRepository kayakRepository;  

public KayakController(KayakRepository kayakRepository) {
    this.kayakRepository = kayakRepository;
}

@PostMapping()  
public @ResponseBody  
Mono&lt;Kayak&gt; addKayak(@RequestBody Kayak kayak) {  
    return kayakRepository.save(kayak);  
}  

@GetMapping()  
public @ResponseBody  
Flux&lt;Kayak&gt; getAllKayaks() {  
    return kayakRepository.findAll();  
}

}

This controller adds two endpoints:

  • POST /kayaks that adds a new kayak
  • GET /kayaks that lists all of the kayaks

You’ll also notice that the class uses Spring dependency injection to autowire the KayakRepository instance into the controller, and you’ll see how the Kayak domain class is being persisted using the repository.

This class looks an awful lot like a relational, blocking version. A lot of behind the scenes work goes into making this the case. Have no fear, however, this is 100% reactive, non-blocking code.


Test Your Spring Boot Server

At this point, you have a fully operational kayak REST resource server. Before you test it, add the following method to your MainApplication class. This simply injects some test data into the database when the application loads.

@Bean
ApplicationRunner init(KayakRepository repository) {

Object[][] data = {
{"sea", "Andrew", 300.12, "NDK"},
{"creek", "Andrew", 100.75, "Piranha"},
{"loaner", "Andrew", 75, "Necky"}
};

return args -> {
repository
.deleteAll()
.thenMany(
Flux
.just(data)
.map(array -> {
return new Kayak((String) array[0], (String) array[1], (Number) array[2], (String) array[3]);
})
.flatMap(repository::save)
)
.thenMany(repository.findAll())
.subscribe(kayak -> System.out.println("saving " + kayak.toString()));
};
}

HTTPie is a great command line utility that makes it easy to run requests against the resource server. If you don’t have HTTPie installed, install it using brew install httpie. Or head over to their website and make it happen. Or just follow along.

Make sure your Spring Boot app is running. If it isn’t, start it using ./gradlew bootRun.

Run a GET request against your resource server: http :8080/kayaks, which is shorthand for http GET http://localhost:8080/kayaks.

You’ll get this:

HTTP/1.1 200 OK
Content-Type: application/json;charset=UTF-8
transfer-encoding: chunked
[
{
"makeModel": "NDK",
"name": "sea",
"owner": "Andrew",
"value": 300.12
},
{
"makeModel": "Piranha",
"name": "creek",
"owner": "Andrew",
"value": 100.75
},
{
"makeModel": "Necky",
"name": "loaner",
"owner": "Andrew",
"value": 75
}
]

Now try POST’ing a new kayak to the server.

http POST :8080/kayaks name="sea2" owner="Andrew" value="500" makeModel="P&H"

You should see:

HTTP/1.1 200 OK
Content-Length: 62
Content-Type: application/json;charset=UTF-8
{
"makeModel": "P&H",
"name": "sea2",
"owner": "Andrew",
"value": 500
}

And if you repeat the GET request, http :8080/kayaks, you’ll see the new kayak in the list!


Set Up Secure Authentication

Now you need to integrate Okta for OAuth 2.0 and add token-based authentication to the resource server. This section is exactly the same as the section in Part 1 of this tutorial, so if you’ve already done that, all you need is your Client ID, and you can skip forward to to the next section.

If you haven’t already, head over to developer.okta.com and sign up for a free account. Once you have an account, open the developer dashboard and create an OpenID Connect (OIDC) application by clicking on the Application top-menu item, and then on the Add Application button.

Select Single-Page App.

The default application settings are great, except that you need to add a Login Redirect URI: https://oidcdebugger.com/debug. You’re going to use this in a moment to retrieve a test token.

NOTE: If you’re implementing a front end like Angular or React, you may need to update the default login redirect URI depending on the platform you’re using. Because this tutorial is only creating a resource server without a front end, it doesn’t really matter for the moment. All our resource server will be doing is validating the JSON web token with the authorization server, which doesn’t require a redirect.

Also, note your Client ID, as you’ll need that in a moment.


Configure Your Spring Boot Server for Token Authentication

Now you need to update a few project files to configure Spring Boot for OAuth 2.0.

Add the following dependencies to your build.gradle file:

dependencies {
...
compile('com.okta.spring:okta-spring-boot-starter:1.1.0')
...
}

Create a new configuration file called src/main/resources/application.yml

okta:
oauth2:
issuer: https://{yourOktaDomain}/oauth2/default
groupsClaim: groups
clientId: {yourClientId}

Create a SecurityConfiguration.java class in the com.okta.springbootmongo package:

package com.okta.springbootmongo;

import org.springframework.context.annotation.Bean;
import org.springframework.security.config.annotation.web.reactive.EnableWebFluxSecurity;
import org.springframework.security.config.web.server.ServerHttpSecurity;
import org.springframework.security.web.server.SecurityWebFilterChain;

@EnableWebFluxSecurity
public class SecurityConfiguration {

@Bean
public SecurityWebFilterChain securityWebFilterChain(ServerHttpSecurity http) {
    http
        .authorizeExchange()
        .anyExchange().authenticated()
        .and()
        .oauth2ResourceServer()
        .jwt();
    return http.build();
}

}

Test Your Protected Server

Stop your Spring Boot server and restart it using: ./gradlew bootRun

From the command line, run a simple GET request.

http :8080/kayaks

You’ll get a 401/unauthorized.

HTTP/1.1 401 Unauthorized
Cache-Control: no-store
Content-Type: application/json;charset=UTF-8

Generate an Access Token

To access the server now, you need a valid access token. You can use OpenID Connect debugger to help you do this. In another window, open oidcdebugger.com.

  • Authorize URI: <span
  • class="okta-preview-domain"><span
  • class="okta-preview-domain">https://{yourOktaDomain}</span></span>/oauth2/default/v1/authorize
  • Redirect URI: do not change. This is the value you added to your OIDC application above.
  • Client ID: from the OIDC application you just created.
  • Scope: openid profile email.
  • State: any value you want to pass through the OAuth redirect process. I set it to {}.
  • Nonce: can be left alone. Nonce means “number used once” and is a simple security measure used to prevent the same request being used multiple times.
  • Response Type: token.
  • Response mode: form_post.

Click Send Request. If you are not logged into developer.okta.com, then you’ll be required to log in. If you are (as is likely) already logged in, then the token will be generated for your signed-in identity.


Use Your Access Token

You use the token by including in an Authorization request header of type Bearer.

Store the token in a shell variable:

TOKEN=eyJraWQiOiJldjFpay1DS3UzYjJXS3QzSVl1MlJZc3VJSzBBYUl3NkU4SDJfNVJr...

Then make a GET request with HTTPie:

http :8080/kayaks "Authorization: Bearer $TOKEN"

Note the double quotes above. Single quotes do not work because the shell variable is not expanded.


Add Group-Based Authorization

Now you’re going to make the authorization scheme a little more refined by adding the ability to control access to specific controller endpoints based on Group membership.

To use group-based authorization with Okta, you need to add a “groups” claim to your access token. Create an Admin group (Users > Groups > Add Group) and add your user to it. You can use the account you signed up with, or create a new user (Users > Add Person). Navigate to API > Authorization Servers, click the Authorization Servers tab and edit the default one. Click the Claims tab and Add Claim. Name it “groups”, and include it in the access token. Set the value type to “Groups” and set the filter to be a Regex of .*.

The groups claim carries the groups to which the user is assigned. The default user you’re using to sign into the developer.okta.com website will also be a member of both the “Everyone” group and the “Admin” group.

The SecurityConfiguration class also needs to be updated to use group-based authorization. Update the Java file to match the following:

package com.okta.springbootmongo;

import org.springframework.context.annotation.Bean;
import org.springframework.http.HttpMethod;
import org.springframework.security.config.annotation.method.configuration.EnableReactiveMethodSecurity;
import org.springframework.security.config.annotation.web.reactive.EnableWebFluxSecurity;
import org.springframework.security.config.web.server.ServerHttpSecurity;
import org.springframework.security.web.server.SecurityWebFilterChain;

@EnableWebFluxSecurity
@EnableReactiveMethodSecurity
public class SecurityConfiguration {

@Bean
public SecurityWebFilterChain securityWebFilterChain(ServerHttpSecurity http) {
http
.authorizeExchange()
.pathMatchers(HttpMethod.POST, "/kayaks/**").hasAuthority("Admin")
.anyExchange().authenticated()
.and()
.oauth2ResourceServer()
.jwt();
return http.build();
}
}

In simple English, this tells Spring Boot to require the group membership Admin for any POST to the /kayak endpoint, and for all other requests, simply require a valid JWT.

Your group-based authorization policy is defined by these two lines:

.pathMatchers(HttpMethod.POST, "/kayaks/**").hasAuthority("Admin")
.anyExchange().authenticated()

For more information, take a look at the ServerHttpSecurity class’s documentation.

You might be wondering why it says hasAuthority() instead of hasRole() or hasGroup(). This is because authorities are what Spring calls the text strings sent by the server to denote permission membership, be it roles or groups. hasRole() assumes that roles are in a specific format: “ROLE_ADMIN”. This can be overridden, but hasAuthority() is a simple way to use the authority string directly. There is no hasGroup() method, as this use case is covered by the former two examples, if not explicitly.


Create a Non-Admin User

To test your group-based authorization scheme, you need a user that isn’t an admin. Go to the developer.okta.com dashboard.

From the top-menu, select Users > People. Click the Add Person button.

Give the user a First Name, Last Name, and Username (which will also be the Primary Email). The values do not matter, and you won’t need to be able to check the email. You simply need to know the email address/username and password so you can log in to Okta in a minute.

Password: change the drop down to Set by admin.

Assign the user a password.

Click Save.

You’ve just created a user that is NOT a member of the Admin group but is a member of the default group Everyone.


Test Group-Based Authorization

Log out of your Okta developer dashboard.

Return to the OIDC Debugger and generate a new token.

This time, log in as your new non-admin user. You’ll be asked to choose a security question, after which you’ll be redirected to the https://oidcdebugger.com/debug page where your token can be copied.

If you like, you can go to jsonwebtoken.io and decode your new token. In the payload, the sub claim will show the email/username of the user, and the groups claim will show only the Everyone group.

{
"sub": "[email protected]",
"groups": [
"Everyone"
]
}

According to the permission scheme, this user should be able to list all kayaks but shouldn’t be able to add a new kayak.

Remember, store your token in a shell script like so:

TOKEN=eyJraWQiOiI4UlE5REJGVUJOTnJER0VGaEExekd6bWJqREpSYTRTT1lhaGpsM3d4...

Make a GET request to list all kayaks:

http :8080/kayaks "Authorization: Bearer $TOKEN"

HTTP/1.1 200 OK
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Content-Type: application/json;charset=UTF-8
...

[
{
"makeModel": "NDK",
"name": "sea",
"owner": "Andrew",
"value": 300.12
},
{
"makeModel": "Necky",
"name": "loaner",
"owner": "Andrew",
"value": 75
},
{
"makeModel": "Piranha",
"name": "creek",
"owner": "Andrew",
"value": 100.75
}
]

Try to add a new kayak using the non-admin user token:

http POST :8080/kayaks "Authorization: Bearer $TOKEN" name="sea2" owner="Andrew" value="500" makeModel="P&H"

You’ll be denied!

HTTP/1.1 403 Forbidden
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Expires: 0
...

Now, log out of developer.okta.com, and generate a new token using the OIDC Debugger. This time log back in with your original, admin account.

Store the new token in the shell variable TOKEN.

Run the POST request:

http POST :8080/kayaks "Authorization: Bearer $TOKEN" name="sea2" owner="Andrew" value="500" makeModel="P&H"

BAM! 💥

HTTP/1.1 200 OK
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
...
{
"makeModel": "P&H",
"name": "sea2",
"owner": "Andrew",
"value": 500
}

All’s Well that Ends Authenticated

That’s it! In this tutorial, you created a Spring Boot application with Spring WebFlux, used an embedded MongoDB database for persisting model classes, and added a resource server to it. After that, I showed you how to add JWT token authentication using Okta and OAuth 2.0. Finally, you saw how to use Okta and Spring Security to add group-based authorization to specific endpoints in a controller.

If you’d like to check out this complete project, you can find the repo on GitHub at oktadeveloper/okta-spring-boot-mongo-webflux-example.

If you haven’t already, check out Part 1 of this series: Build a Basic App with Spring Boot and JPA using PostgreSQL. It’s the same app, but using a more traditional relational database and Spring MVC-style blocking web server.


Learn More

The Complete Developers Guide to MongoDB

Master MongoDB, the NOSQL leader with Clarity and Confidence

MongoDB, NoSQL & Node: Mongoose, Azure & Database Management

Build a ChatApp with: (Nodejs,Socketio, Expressjs ,MongoDB)

GraphQL: Learning GraphQL with Node.Js

Complete Java Masterclass

Complete Step By Step Java For Testers

Java Web Service Complete Guide - SOAP + REST + Buide App

Selenium WebDriver with Java - Basics to Advanced& Interview

Java Persistence: Hibernate and JPA Fundamentals

Java Swing (GUI) Programming: From Beginner to Expert

Originally published by Andrew Hughes at https://developer.okta.com

Building a simple Slack Bot using Spring Boot and MongoDB

Building a simple Slack Bot using Spring Boot and MongoDB

Step by step tutorial of building a simple Slack Bot using Spring Boot and MongoDB as a worker

A simple step by step tutorial of building a simple Slack Bot using Spring Boot and MongoDB as a Worker. Slack is an acronym for Searchable Log of All Conversation and Knowledge. Slack offers many IRC-like features, including persistent chat rooms (channels) organized by topic, private groups, and direct messaging. Content, including files, conversations, and people, is all searchable within Slack. Users can add emoji buttons to their messages, on which other users can then click to express their reactions to messages. This Slack Bot application using the JBot library. Actually, there's a lot of Slack Bot library for Java (find here), but we just want to try this JBot library.

Table of Contents:

  • Create a Slack App
  • Generate Spring Boot Application
  • Create Java Model or Entity Class
  • Create Java Repository Interface for BadWord Model
  • Add and Configure JBot Java Library
  • Implement Bot Method on Spring Boot Java Application
  • Run and Test the Spring Boot MongoDB Slack Bot

Bots are like having a virtual team member, they can help you manage tasks, run your team standup, poll the office, and more.

The Scenario for this tutorial is simple, just a Slack Bot for catch the keyword from a conversation or chats that contain harsh words or bad words (ex: fuck, sht, b*tch) then save it to MongoDB include with User who sends it. The Slack will count that words from MongoDB until getting 5 words then the Bot will send back the message to channels to warns the sender of bad words.

The following tools, frameworks, and library are required for this tutorial:

  1. Java 8
  2. Spring Boot
  3. Spring Data MongoDB
  4. MongoDB https://www.mongodb.com/
  5. JBot
  6. Terminal or Command Line
  7. IDE or Text Editor (we are using Netbeans)
  8. Spring Initalizr

We assume that you have installed Java 8, MongoDB and IDE or Text Editor. So, we can continue straight forward to the steps of the tutorial.

Create a Slack App

We need a Slack token before moving to Spring Boot MongoDB Slack Bot tutorial. For that, on the browser go to https://yourworkspace.slack.com/services/new/bot. You will redirect to the login form if not logged in yet. Log in using your workspaces user then you will entering Slack Bot configuration page.

Give username for your bot then click Add Bot Integration button. That's it, now you have your Bot token that ready to use. Save that code somewhere in your local, do not try to save it on public repositories or the bot will be disabled by Slack.

Generate Spring Boot Application

As our previous Spring Boot tutorial, we will generate a Spring Boot application online by going to Spring Initalizr on the browser.

Choose to generate a Gradle project with Java and Spring Boot 1.5.9. In Project metadata fill artifact coordinate group with your package ID (example: com.djamware) and artifact by your app name (example: slackbot). Search dependencies for the term of MongoDB. Finally, click Generate Project button to generate and download a zip file contains the initial Spring Boot project.

Extract that zip file to your workspace or projects folder. Now, open the project in the Netbeans. It will load all dependencies automatically, just wait until finished. After that, you will see the directory structure like this in the files navigation.

Create Java Model or Entity Class

Every bad word catch from Slack message save to MongoDB collection including the sender of the message. For that, we have to create a Java class that represents a model for bad words collection. If you are using Netbeans (similar with some IDE), right-click project name then click New then click Java Class.

Fill necessary fields like above screenshot then click Finish button. Netbeans will automatically open the newly created file, replace all codes with this.

package com.djamware.slackbot.models;

import java.util.Date;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

@Document(collection = "badwords")
public class BadWord {
    @Id
    String id;
    String user;
    String word;
    Date updateDate = new Date();

    public BadWord() {
    }

    public BadWord(String user, String word, Date updateDate) {
        this.user = user;
        this.word = word;
        this.updateDate = updateDate;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getUser() {
        return user;
    }

    public void setUser(String user) {
        this.user = user;
    }

    public String getWord() {
        return word;
    }

    public void setWord(String word) {
        this.word = word;
    }

    public Date getUpdateDate() {
        return updateDate;
    }

    public void setUpdateDate(Date updateDate) {
        this.updateDate = updateDate;
    }
}

That BadWord class mapping to badword collections of MongoDB which has 4 fields (id, user, word, updateDate). Each field has getter and setter except for updateDate has a default value for the current date.

Don't forget to add MongoDB configuration to the src/main/recources/application.properties.

spring.data.mongodb.database=slackbot
spring.data.mongodb.host=localhost
spring.data.mongodb.port=27017
Create Java Repository Interface for BadWord Model

Now, we need to create an interface for connecting the BadWord model and controller. On Netbeans right-click project name on projects left panel then choose New then choose Java Interface. On the New Java Interface dialog, git it name BadwordRepository and package name com.djamware.slackbot.repositories then click Finish button.

Next, replace all codes with these few lines of codes.

package com.djamware.slackbot.repositories;

import com.djamware.slackbot.models.BadWord;
import org.springframework.data.repository.CrudRepository;

public interface BadwordRepository extends CrudRepository<BadWord, String> {

}
Add and Configure JBot Java Library

Back to business, open and edit build.gradle from the root of the project folder. Add JBot dependencies to dependencies block.

dependencies {
    compile('org.springframework.boot:spring-boot-starter-data-mongodb')
    testCompile('org.springframework.boot:spring-boot-starter-test')
    compile("me.ramswaroop.jbot:jbot:3.0.2")
}

Then run compile by open the Run menu then choose compile file or just click on F9 key. Now, the library is ready to use with your Java application.

Implement Bot Method on Spring Boot Java Application

It's time to make a Java Slack Bot with Spring Boot. Open application.properties on the src/main/resources folder then add these lines of codes.

rtmUrl=https://slack.com/api/rtm.start?token={token}&simple_latest&no_unreads
slackBotToken=your-slack-bot-token

Next, create a Class file in the package com.djamware.slackbot.bot with the name of the file SlackBot.java. After the new class file opened, add extends to the class name and add annotation above the class name.

@Component
public class SlackBot extends Bot {

}

Declare the variable for logger on the first line of the class body.

private static final Logger logger = LoggerFactory.getLogger(SlackBot.class);

Declare a variable for getting the token which handles by JBot library.

@Value("${slackBotToken}")
private String slackToken;

Next, create getter methods for token and JBot library.

@Override
public String getSlackToken() {
    return slackToken;
}

@Override
public Bot getSlackBot() {
    return this;
}

Now, create a method for receiving a direct message (DM) to the Slack Bot.

@Controller(events = {EventType.DIRECT_MENTION, EventType.DIRECT_MESSAGE})
public void onReceiveDM(WebSocketSession session, Event event) {
    reply(session, event, new Message("Hi, I am " + slackService.getCurrentUser().getName()));
}

For catching bad words, we have to add a method onReceiveMessage and create a filter by message string pattern.

@Controller(events = EventType.MESSAGE, pattern = "fuck|shit|bitch")
public void onReceiveMessage(WebSocketSession session, Event event, Matcher matcher) {
    if(!matcher.group(0).isEmpty()) {
        BadWord badword = new BadWord(event.getUserId(),matcher.group(0));
        badwordRepository.save(badword);
        Integer countBadWords = badwordRepository.countByUser(event.getUserId());
        if(countBadWords >= 5) {
            reply(session, event, new Message("Enough! You have too many say bad words. \nThe admin will kick you away from this channel."));
        } else {
            reply(session, event, new Message("Becareful you have say bad words "+countBadWords+" times"));
        }
    }
}

The bad words declare the pattern if found one of them then save it to the database. After save, count by user ID then check if bad words exceed the maximum allowed 5 words then the response to the channel with a warning message.

Run and Test the Spring Boot MongoDB Slack Bot

To test and run the Slack Bot application on the local machine, make sure your MongoDB is running. Then open another terminal to run the Slack Bot by typing this command in the project directory.

./gradlew bootrun

Open the Slack app from your browser or desktop app then log on to it. Create a new channel from the left navigation menu of the Slack app.

Then fill the new Channel form like below.

Click Create Channel button to finish. Now, your channel is ready. Type something contains bad words in the text field below the Slack App. If it catches then you will get the response like this.

That's it, a simple Slack Bot example using Spring Boot, MongoDB, and JBot. Actually, JBot getUser() method returns null so for saving user who types the bad word to DB using user ID. There's some Slack Bot library for Java out there that might be fit for your requirements, this is just an example of Slack Bot integration. For the full working Source Code, you can find in our GitHub.