🚧 work in propress for bucket4j rate limit

IOT-Guide-RateLimiting/src/main/java/iot/technology/ratelimiting/RateLimitApplication.java

@@ -1,13 +1,28 @@
 package iot.technology.ratelimiting;
 
+import iot.technology.ratelimiting.bucket4j.interceptor.RateLimitInterceptor;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Lazy;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
 /**
  * @author mushuwei
  */
 @SpringBootApplication(scanBasePackages = {"iot.technology.ratelimiting"})
-public class RateLimitApplication {
+public class RateLimitApplication implements WebMvcConfigurer {
+
+    @Autowired
+    @Lazy
+    private RateLimitInterceptor interceptor;
+
+    @Override
+    public void addInterceptors(InterceptorRegistry registry) {
+        registry.addInterceptor(interceptor)
+                .addPathPatterns("/api/v1/area/**");
+    }
 
     public static void main(String[] args) {
         SpringApplication.run(RateLimitApplication.class);

IOT-Guide-RateLimiting/src/main/java/iot/technology/ratelimiting/bucket4j/PricingPlan.java

@@ -0,0 +1,44 @@
+package iot.technology.ratelimiting.bucket4j;
+
+import io.github.bucket4j.Bandwidth;
+import io.github.bucket4j.Refill;
+
+import java.time.Duration;
+
+/**
+ * @author mushuwei
+ */
+public enum PricingPlan {
+
+    FREE(20),
+
+    BASIC(40),
+
+    PROFESSIONAL(100);
+
+    private int bucketCapacity;
+
+    private PricingPlan(int bucketCapacity) {
+        this.bucketCapacity = bucketCapacity;
+    }
+
+    Bandwidth getLimit() {
+        return Bandwidth.classic(bucketCapacity, Refill.intervally(bucketCapacity, Duration.ofHours(1)));
+    }
+
+    public int bucketCapacity() {
+        return bucketCapacity;
+    }
+
+    static PricingPlan resolvePlanFromApiKey(String apiKey) {
+        if (apiKey == null || apiKey.isEmpty()) {
+            return FREE;
+        } else if (apiKey.startsWith("PX001-")) {
+            return PROFESSIONAL;
+        } else if (apiKey.startsWith("BX001-")) {
+            return BASIC;
+        }
+        return FREE;
+    }
+
+}

IOT-Guide-RateLimiting/src/main/java/iot/technology/ratelimiting/bucket4j/PricingPlanService.java

@@ -0,0 +1,33 @@
+package iot.technology.ratelimiting.bucket4j;
+
+import io.github.bucket4j.Bandwidth;
+import io.github.bucket4j.Bucket;
+import io.github.bucket4j.Bucket4j;
+import org.springframework.stereotype.Service;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * @author mushuwei
+ */
+@Service
+public class PricingPlanService {
+
+    private final Map<String, Bucket> cache = new ConcurrentHashMap<>();
+
+    public Bucket resolveBucket(String apiKey) {
+        return cache.computeIfAbsent(apiKey, this::newBucket);
+    }
+
+    private Bucket newBucket(String apiKey) {
+        PricingPlan pricingPlan = PricingPlan.resolvePlanFromApiKey(apiKey);
+        return bucket(pricingPlan.getLimit());
+    }
+
+    private Bucket bucket(Bandwidth limit) {
+        return Bucket4j.builder()
+                .addLimit(limit)
+                .build();
+    }
+}

IOT-Guide-RateLimiting/src/main/java/iot/technology/ratelimiting/bucket4j/interceptor/RateLimitInterceptor.java

@@ -0,0 +1,51 @@
+package iot.technology.ratelimiting.bucket4j.interceptor;
+
+import io.github.bucket4j.Bucket;
+import io.github.bucket4j.ConsumptionProbe;
+import iot.technology.ratelimiting.bucket4j.PricingPlanService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.HandlerInterceptor;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * @author mushuwei
+ */
+@Component
+public class RateLimitInterceptor implements HandlerInterceptor {
+
+    private static final String HEADER_API_KEY = "X-api-key";
+    public static final String HEADER_LIMIT_REMAINING = "X-Rate-Limit-Remaining";
+    public static final String HEADER_RETRY_AFTER = "X-Rate-Limit-Retry-After-Seconds";
+
+    @Autowired
+    private PricingPlanService pricingPlanService;
+
+    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
+        String apiKey = request.getHeader(HEADER_API_KEY);
+
+        if (apiKey == null || apiKey.isEmpty()) {
+            response.sendError(HttpStatus.BAD_REQUEST.value(), "Missing Header: " + HEADER_API_KEY);
+        }
+        Bucket tokenBucket = pricingPlanService.resolveBucket(apiKey);
+        ConsumptionProbe probe = tokenBucket.tryConsumeAndReturnRemaining(1);
+
+        if (probe.isConsumed()) {
+            response.addHeader(HEADER_LIMIT_REMAINING, String.valueOf(probe.getRemainingTokens()));
+            return true;
+        } else {
+            long waitForRefill = probe.getNanosToWaitForRefill() / 1_000_000_000;
+
+            response.setContentType(MediaType.APPLICATION_JSON_VALUE);
+            response.addHeader(HEADER_RETRY_AFTER, String.valueOf(waitForRefill));
+            response.sendError(HttpStatus.TOO_MANY_REQUESTS.value(), "You have exhausted your API Request Quota");
+            return false;
+        }
+
+    }
+
+}

IOT-Guide-RateLimiting/src/main/java/iot/technology/ratelimiting/config/AppConfig.java

@@ -0,0 +1,11 @@
+package iot.technology.ratelimiting.config;
+
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+
+/**
+ * @author mushuwei
+ */
+public class AppConfig implements WebMvcConfigurer {
+
+
+}

IOT-Guide-RateLimiting/src/test/java/iot/technology/ratelimiting/api-ratelimiting.http

@@ -1,6 +1,7 @@
 ### 1.计算长方形面积
 POST localhost:8080/api/v1/area/rectangle
 Content-Type: application/json
+X-api-key: FX001-99999
 
 {
   "length": "10",