Migrate backend from Node.js/TypeScript/Express to Java Spring Boot

backend/.gitignore

@@ -1,4 +1,16 @@
-config.ts
-dist
-node_modules
-.env
+# Maven build output
+target/
+
+# IDE files
+.idea/
+*.iml
+.classpath
+.project
+.settings/
+*.class
+
+# Environment / secrets
+.env
+
+# macOS
+.DS_Store

backend/pom.xml

@@ -0,0 +1,90 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.4.3</version>
+        <relativePath/>
+    </parent>
+
+    <groupId>com.secondbrain</groupId>
+    <artifactId>second-brain</artifactId>
+    <version>1.0.0</version>
+    <name>second-brain</name>
+    <description>Second Brain API - Spring Boot</description>
+
+    <properties>
+        <java.version>17</java.version>
+        <jjwt.version>0.12.6</jjwt.version>
+    </properties>
+
+    <dependencies>
+        <!-- Spring Web -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <!-- Spring Data MongoDB -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-mongodb</artifactId>
+        </dependency>
+
+        <!-- Spring Security -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-security</artifactId>
+        </dependency>
+
+        <!-- Spring Validation -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
+        </dependency>
+
+        <!-- JJWT -->
+        <dependency>
+            <groupId>io.jsonwebtoken</groupId>
+            <artifactId>jjwt-api</artifactId>
+            <version>${jjwt.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>io.jsonwebtoken</groupId>
+            <artifactId>jjwt-impl</artifactId>
+            <version>${jjwt.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.jsonwebtoken</groupId>
+            <artifactId>jjwt-jackson</artifactId>
+            <version>${jjwt.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+
+        <!-- Test -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+</project>

backend/src/main/java/com/secondbrain/SecondBrainApplication.java

@@ -0,0 +1,12 @@
+package com.secondbrain;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SecondBrainApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SecondBrainApplication.class, args);
+    }
+}

backend/src/main/java/com/secondbrain/config/SecurityConfig.java

@@ -0,0 +1,68 @@
+package com.secondbrain.config;
+
+import java.util.Arrays;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpMethod;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.http.SessionCreationPolicy;
+import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.web.SecurityFilterChain;
+import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;
+import org.springframework.web.cors.CorsConfiguration;
+import org.springframework.web.cors.CorsConfigurationSource;
+import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
+
+import com.secondbrain.security.JwtAuthFilter;
+
+@Configuration
+@EnableWebSecurity
+public class SecurityConfig {
+
+    @Autowired
+    private JwtAuthFilter jwtAuthFilter;
+
+    @Bean
+    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
+        http
+            // CSRF is disabled because this is a stateless REST API using JWT in the
+            // Authorization header. Browsers cannot be tricked into sending that header
+            // cross-site, so CSRF protection is not necessary here.
+            .csrf(csrf -> csrf.disable())
+            .cors(cors -> cors.configurationSource(corsConfigurationSource()))
+            .sessionManagement(session ->
+                session.sessionCreationPolicy(SessionCreationPolicy.STATELESS))
+            .authorizeHttpRequests(auth -> auth
+                .requestMatchers(HttpMethod.GET, "/").permitAll()
+                .requestMatchers(HttpMethod.POST, "/api/v1/user/signup").permitAll()
+                .requestMatchers(HttpMethod.POST, "/api/v1/user/signin").permitAll()
+                .requestMatchers(HttpMethod.GET, "/api/v1/brain/**").permitAll()
+                .anyRequest().authenticated()
+            )
+            .addFilterBefore(jwtAuthFilter, UsernamePasswordAuthenticationFilter.class);
+
+        return http.build();
+    }
+
+    @Bean
+    public PasswordEncoder passwordEncoder() {
+        return new BCryptPasswordEncoder();
+    }
+
+    @Bean
+    public CorsConfigurationSource corsConfigurationSource() {
+        CorsConfiguration config = new CorsConfiguration();
+        config.setAllowedOriginPatterns(Arrays.asList("*"));
+        config.setAllowedMethods(Arrays.asList("GET", "POST", "PUT", "DELETE", "OPTIONS"));
+        config.setAllowedHeaders(Arrays.asList("*"));
+        config.setAllowCredentials(false);
+
+        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
+        source.registerCorsConfiguration("/**", config);
+        return source;
+    }
+}

backend/src/main/java/com/secondbrain/controller/ContentController.java

@@ -0,0 +1,61 @@
+package com.secondbrain.controller;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.core.Authentication;
+import org.springframework.web.bind.annotation.DeleteMapping;
+import org.springframework.web.bind.annotation.GetMapping;
+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.secondbrain.dto.ContentRequest;
+import com.secondbrain.model.Content;
+import com.secondbrain.repository.ContentRepository;
+
+import jakarta.validation.Valid;
+
+@RestController
+@RequestMapping("/api/v1/content")
+public class ContentController {
+
+    @Autowired
+    private ContentRepository contentRepository;
+
+    @PostMapping
+    public ResponseEntity<?> create(@Valid @RequestBody ContentRequest request, Authentication auth) {
+        String userId = (String) auth.getPrincipal();
+
+        Content content = new Content();
+        content.setTitle(request.getTitle());
+        content.setLink(request.getLink());
+        content.setType(request.getType());
+        content.setUserId(userId);
+        content.setTags(Collections.emptyList());
+
+        contentRepository.save(content);
+        return ResponseEntity.ok(Map.of("message", "Content added"));
+    }
+
+    @GetMapping
+    public ResponseEntity<?> list(Authentication auth) {
+        String userId = (String) auth.getPrincipal();
+        List<Content> content = contentRepository.findByUserId(userId);
+        return ResponseEntity.ok(Map.of("content", content));
+    }
+
+    @DeleteMapping
+    public ResponseEntity<?> delete(@RequestBody Map<String, String> body, Authentication auth) {
+        String userId = (String) auth.getPrincipal();
+        String contentId = body.get("contenetId");
+        if (contentId != null) {
+            contentRepository.deleteByIdAndUserId(contentId, userId);
+        }
+        return ResponseEntity.ok(Map.of("message", "Deleted"));
+    }
+}

backend/src/main/java/com/secondbrain/controller/RootController.java

@@ -0,0 +1,13 @@
+package com.secondbrain.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class RootController {
+
+    @GetMapping("/")
+    public String root() {
+        return "Hello";
+    }
+}