Toàn tập về Redis Caching

@Configuration
@EnableRedisHttpSession
public class SessionConfig {
    @Bean
    public LettuceConnectionFactory connectionFactory() {
        return new LettuceConnectionFactory();
    }
}

@RestController
public class SessionController {

    @GetMapping("/session")
    public String handleSession(HttpSession session) {
        Integer views = (Integer) session.getAttribute("views");
        if (views == null) {
            views = 0;
            session.setAttribute("views", 1);
            return "Welcome to this page for the first time!";
        } else {
            session.setAttribute("views", views + 1);
            return "You visited this page " + views + " times";
        }
    }
}
                                    

@Service
public class RateLimiterService {

    @Autowired
    private RedisTemplate redisTemplate;

    private static final int LIMIT = 10; // 10 requests
    private static final int PERIOD = 60; // per 60 seconds

    public boolean isRateLimited(String userId) {
        String key = "rate_limit:" + userId;
        String count = redisTemplate.opsForValue().get(key);

        if (count == null) {
            redisTemplate.opsForValue().set(key, "1", PERIOD, TimeUnit.SECONDS);
            return false;
        }

        Long currentCount = Long.parseLong(count);
        if (currentCount >= LIMIT) {
            return true; // Bị giới hạn
        }

        redisTemplate.opsForValue().increment(key, 1);
        return false; // Cho phép
    }
}

@RestController
public class RateLimitController {

    @Autowired
    private RateLimiterService rateLimiterService;

    @GetMapping("/api")
    public ResponseEntity accessApi(@RequestParam String userId) {
        if (rateLimiterService.isRateLimited(userId)) {
            return ResponseEntity.status(HttpStatus.TOO_MANY_REQUESTS)
                    .body("Rate limit exceeded for user: " + userId);
        }
        return ResponseEntity.ok("Request allowed for user: " + userId);
    }
}
                                    

@Service
public class LeaderboardService {

    @Autowired
    private RedisTemplate redisTemplate;

    private static final String LEADERBOARD_KEY = "game:leaderboard";

    public void addScore(String userId, double score) {
        redisTemplate.opsForZSet().add(LEADERBOARD_KEY, userId, score);
    }

    public List getTopPlayers(int limit) {
        Set topPlayers = redisTemplate.opsForZSet()
                .reverseRange(LEADERBOARD_KEY, 0, limit - 1);
        return new ArrayList<>(topPlayers);
    }

    public Long getRank(String userId) {
        return redisTemplate.opsForZSet().reverseRank(LEADERBOARD_KEY, userId);
    }
}

@RestController
@RequestMapping("/leaderboard")
public class LeaderboardController {

    @Autowired
    private LeaderboardService leaderboardService;

    @PostMapping("/score")
    public ResponseEntity addScore(@RequestParam String userId, @RequestParam double score) {
        leaderboardService.addScore(userId, score);
        return ResponseEntity.ok("Score added for user: " + userId);
    }

    @GetMapping("/top")
    public ResponseEntity> getTopPlayers(@RequestParam(defaultValue = "10") int limit) {
        return ResponseEntity.ok(leaderboardService.getTopPlayers(limit));
    }

    @GetMapping("/rank")
    public ResponseEntity getRank(@RequestParam String userId) {
        Long rank = leaderboardService.getRank(userId);
        return ResponseEntity.ok(rank != null ? rank : -1);
    }
}