59. Brute force attack cache - Guava LoadingCache Service Implementation (#6)

support-portal-backend/pom.xml

@@ -60,6 +60,12 @@
             <version>3.12.0</version>
         </dependency>
 
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>30.1.1-jre</version>
+        </dependency>
+
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>

support-portal-backend/src/main/java/net/shyshkin/study/fullstack/supportportal/backend/service/GuavaCacheLoginAttemptService.java

@@ -0,0 +1,46 @@
+package net.shyshkin.study.fullstack.supportportal.backend.service;
+
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import org.springframework.context.annotation.Primary;
+import org.springframework.stereotype.Service;
+
+import java.util.Objects;
+import java.util.concurrent.TimeUnit;
+
+@Service
+@Primary
+public class GuavaCacheLoginAttemptService implements LoginAttemptService {
+
+    private LoadingCache<String, Integer> loginAttemptsCache = CacheBuilder.newBuilder()
+            .expireAfterWrite(15, TimeUnit.MINUTES)
+            .maximumSize(100)
+            .build(new CacheLoader<>() {
+                @Override
+                public Integer load(String key) throws Exception {
+                    return 0;
+                }
+            });
+
+    @Override
+    public void loginFailed(String username) {
+        int attempts = getAttempts(username);
+        loginAttemptsCache.put(username, attempts + ATTEMPT_INCREMENT);
+    }
+
+    @Override
+    public void loginSucceeded(String username) {
+        loginAttemptsCache.invalidate(username);
+    }
+
+    @Override
+    public boolean hasExceededMaxAttempts(String username) {
+        return getAttempts(username) >= MAX_ATTEMPTS;
+    }
+
+    private int getAttempts(String username) {
+        Integer attempts = loginAttemptsCache.getIfPresent(username);
+        return Objects.requireNonNullElse(attempts, 0);
+    }
+}