API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) · 강의

전역 필터 및 GatewayFilterFactory

전역 필터의 개념과 일반적인 변환에 내장 GatewayFilterFactories를 사용하는 방법을 이해해 보세요.

전역 필터 및 GatewayFilterFactory은(는) CoddyKit의 무료 API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) 강의입니다. 이것은 4개 중 1번째 강의입니다. 아래에서 전체 강의를 무료로 읽을 수 있으며, 내장 코드 에디터와 24/7 AI 튜터와 함께 브라우저에서 직접 실습할 수 있습니다. 이 강의는 API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) 학습 경로의 일부이며, 진행 상황이 웹과 CoddyKit 앱에 동기화됩니다. API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) 강의에는 총 4개의 강의가 포함되어 있습니다.

이 강의의 일부는 아직 번역되지 않았으며 영어로 표시됩니다.

What are Gateway Filters?

In Spring Cloud Gateway, filters are like interceptors that allow you to modify incoming HTTP requests or outgoing HTTP responses.

They provide a powerful way to implement cross-cutting concerns for your API traffic, such as security, logging, or data transformation.

Pre- and Post-Filters

Spring Cloud Gateway supports two main types of filter execution:

Pre-filters: Executed before the request is sent to the downstream service. Great for authentication, logging, or modifying request headers.
Post-filters: Executed after the response is received from the downstream service but before it's sent back to the client. Useful for modifying responses, caching, or error handling.

Understanding Global Filters

A Global Filter is applied to every single request that passes through the gateway, regardless of the specific route it matches.

This makes them ideal for concerns that affect all your API traffic, like global logging, security checks, or metrics collection across all services.

They implement the GlobalFilter interface.

Building a Custom Global Filter

Let's create a simple global filter that logs the incoming request path. It needs to implement GlobalFilter and Ordered.

Run this Spring Boot app and access http://localhost:8080/test/hello. You'll see the log in the console!

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.route.RouteLocator;
import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

@SpringBootApplication
public class GatewayApp {

    public static void main(String[] args) {
        SpringApplication.run(GatewayApp.class, args);
    }

    // A simple route for demonstration
    @Bean
    public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
        return builder.routes()
            .route("test_route", r -> r.path("/test/**")
                .uri("http://httpbin.org:80")) // Public test service
            .build();
    }

    @Component
    static class MyLoggingFilter implements GlobalFilter, Ordered {
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            System.out.println("Global Filter: Request Path -> " + exchange.getRequest().getPath());
            return chain.filter(exchange); // Continue filter chain
        }

        @Override
        public int getOrder() {
            return -1; // Execute very early
        }
    }
}

Understanding Filter Order

When multiple filters (global or route-specific) are present, their execution order matters.

Filters that implement the Ordered interface define their priority using the getOrder() method. Lower values mean higher priority (executed earlier).

Negative values: Very high priority.
Positive values: Lower priority.
Filters without an explicit order often run later.

What is a GatewayFilterFactory?

While GlobalFilters apply everywhere, a GatewayFilterFactory provides reusable, configurable filters that you can apply to specific routes.

Spring Cloud Gateway comes with many built-in factories for common tasks, like adding/removing headers, rewriting paths, or applying rate limits. You configure them per route.

AddRequestHeader Factory in Action

The AddRequestHeader factory adds a static header to the request before it's forwarded to the backend service.

Run this example and navigate to http://localhost:8080/add-header/test. The response from httpbin.org will show the added header!

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.gateway.route.RouteLocator;
import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class GatewayApp {

    public static void main(String[] args) {
        SpringApplication.run(GatewayApp.class, args);
    }

    @Bean
    public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
        return builder.routes()
            .route("add_header_route", r -> r.path("/add-header/**")
                .filters(f -> f.addRequestHeader("X-Gateway-Custom", "CoddyKit"))
                .uri("http://httpbin.org:80/headers")) // Shows request headers
            .build();
    }
}

Exploring More Built-in Factories

Spring Cloud Gateway offers many other powerful GatewayFilterFactory implementations:

RemoveRequestHeader: Removes a specified header.
RewritePath: Changes the request URI path.
Retry: Retries failed requests.
RateLimiter: Applies rate limiting to requests.

These factories simplify common gateway tasks without writing custom code.

Global vs. Route-Specific Filters

When should you use a Global Filter versus a GatewayFilterFactory?

Choose Global Filters for: Cross-cutting concerns affecting all requests (e.g., global security, logging).
Choose GatewayFilterFactory (route-specific) for: Logic specific to certain APIs or groups of routes (e.g., API versioning, specific header manipulation, rate limiting on a particular endpoint).

Global Filter Check

Consider a Spring Cloud Gateway application. Which statement is TRUE about Global Filters?

Global Filters & Factories Recap

We've explored Global Filters, which apply to all requests, and learned how to create a custom one. We also introduced GatewayFilterFactory, which offers reusable, configurable filters for specific routes.

Understanding these filter types and when to use them is crucial for building powerful and flexible API Gateways with Spring Cloud Gateway.

자주 묻는 질문

“전역 필터 및 GatewayFilterFactory” 강의는 무료인가요?

네 — “전역 필터 및 GatewayFilterFactory” 전체 내용을 이 웹사이트에서 무료로 읽을 수 있습니다. 인터랙티브하게 실습하려면(내장 코드 에디터와 24/7 AI 튜터), CoddyKit PRO로 업그레이드하면 API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) 강의 전체를 잠금 해제할 수 있습니다. API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) 강의에는 총 4개의 강의가 포함되어 있습니다.

“전역 필터 및 GatewayFilterFactory”에서 뭘 배우나요?

전역 필터의 개념과 일반적인 변환에 내장 GatewayFilterFactories를 사용하는 방법을 이해해 보세요. 브라우저에서 직접 실행하는 실습 코드로 API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)을(를) 배우며, 24/7 AI 튜터가 강의를 진행하면서 질문에 답변해줍니다.

API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)을(를) 시작하는 데 경험이 필요한가요?

사전 경험은 필요하지 않습니다. CoddyKit의 API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)은(는) 초급자부터 고급 학습자까지를 위해 구성되어 있으므로, 여기서 시작하거나 처음부터 시작할 수 있으며 자신의 속도대로 진행할 수 있습니다. 이것은 4개 중 1번째 강의입니다.

“전역 필터 및 GatewayFilterFactory” 강의는 얼마나 걸리나요?

대부분의 CoddyKit 강의는 약 5~10분이 소요됩니다. 각 강의는 간결하고 인터랙티브하여 꾸준한 진행이 가능하며, 웹과 앱에서 중단한 부분부터 바로 시작할 수 있습니다.

이 API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) 강의에서 코드를 작성하고 실행할 수 있나요?

네. 모든 API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway) 강의에는 내장 코드 에디터가 포함되어 있으므로, 브라우저에서 바로 실제 코드를 작성하고 실행한 후 즉시 AI 피드백을 받을 수 있습니다 — 로컬 설정이 필요 없습니다.

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