Move rate limiting examples

spring-cloud-modules/spring-cloud-gateway-2/src/main/java/com/baeldung/springcloudgateway/GatewayApplication

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+package com.baeldung.springcloudgateway;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.PropertySource;
+
+@SpringBootApplication
+public class GatewayApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(GatewayApplication.class, args);
+    }
+
+}

spring-cloud-modules/spring-cloud-gateway-2/src/main/java/com/baeldung/springcloudgateway/ipaddress/IpAddressApplication.java

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+package com.baeldung.springcloudgateway.ipaddress;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.gateway.filter.ratelimit.RedisRateLimiter;
+import org.springframework.cloud.gateway.route.RouteLocator;
+import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.PropertySource;
+
+@SpringBootApplication()
+@PropertySource("classpath:ipaddress-application.properties")
+public class IpAddressApplication {
+    public static void main(String[] args) {
+        SpringApplication.run(IpAddressApplication.class, args);
+    }
+
+    @Bean
+    public RouteLocator myRoutes(RouteLocatorBuilder builder) {
+        return builder.routes()
+                .route("requestratelimiter_route", p -> p
+                        .path("/example")
+                        .filters(f -> f.requestRateLimiter(r -> r.setRateLimiter(redisRateLimiter())))
+                        .uri("http://example.org"))
+                .route("ipaddress_route", p -> p
+                        .path("/example2")
+                        .filters(f -> f.requestRateLimiter(r -> r.setRateLimiter(redisRateLimiter())
+                                .setDenyEmptyKey(false)
+                                .setKeyResolver(new SimpleClientAddressResolver())))
+                        .uri("http://example.org"))
+                .build();
+    }
+
+    @Bean
+    public RedisRateLimiter redisRateLimiter() {
+        return new RedisRateLimiter(1, 1, 1);
+    }
+}

spring-cloud-modules/spring-cloud-gateway-2/src/main/java/com/baeldung/springcloudgateway/ipaddress/ProxiedClientAddressResolver.java

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+package com.baeldung.springcloudgateway.ipaddress;
+
+import org.springframework.cloud.gateway.filter.ratelimit.KeyResolver;
+import org.springframework.cloud.gateway.support.ipresolver.XForwardedRemoteAddressResolver;
+import org.springframework.context.annotation.Primary;
+import org.springframework.stereotype.Component;
+import org.springframework.web.server.ServerWebExchange;
+import reactor.core.publisher.Mono;
+
+import java.net.InetSocketAddress;
+
+@Primary
+@Component
+public class ProxiedClientAddressResolver implements KeyResolver {
+    @Override
+    public Mono<String> resolve(ServerWebExchange exchange) {
+        XForwardedRemoteAddressResolver resolver = XForwardedRemoteAddressResolver.maxTrustedIndex(1);
+        InetSocketAddress inetSocketAddress = resolver.resolve(exchange);
+        return Mono.just(inetSocketAddress.getAddress().getHostAddress());
+    }
+}

spring-cloud-modules/spring-cloud-gateway-2/src/main/java/com/baeldung/springcloudgateway/ipaddress/SimpleClientAddressResolver.java

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+package com.baeldung.springcloudgateway.ipaddress;
+
+import org.springframework.cloud.gateway.filter.ratelimit.KeyResolver;
+import org.springframework.stereotype.Component;
+import org.springframework.web.server.ServerWebExchange;
+import reactor.core.publisher.Mono;
+
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.util.Optional;
+
+@Component
+public class SimpleClientAddressResolver implements KeyResolver {
+    @Override
+    public Mono<String> resolve(ServerWebExchange exchange) {
+        return Optional.ofNullable(exchange.getRequest().getRemoteAddress())
+                .map(InetSocketAddress::getAddress)
+                .map(InetAddress::getHostAddress)
+                .map(Mono::just)
+                .orElse(Mono.empty());
+    }
+}
+