JWT認証と認可
Spring Cloud GatewayにJWTベースの認証と認可を実装し、APIアクセスを保護します。
「JWT認証と認可」はCoddyKit上の無料API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)レッスンです。 これはレッスン1/4です。 下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。 これはAPI Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)コースには全4レッスンが含まれています。
このレッスンの一部はまだ翻訳されておらず、英語で表示されています。
Securing Your API Gateway
In a microservices architecture, securing your APIs is paramount. Spring Cloud Gateway acts as a central entry point, making it the perfect place to enforce security policies.
This lesson focuses on using JSON Web Tokens (JWTs) for both authentication (who is this user?) and authorization (what can this user do?) directly within your Gateway.
Introducing JSON Web Tokens (JWTs)
A JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. It's often used for authentication and information exchange.
- Stateless: The server doesn't need to store session information.
- Self-contained: Contains all the necessary user information and claims.
- Scalable: Easy to use across multiple services without complex session management.
JWT Structure: Header, Payload, Signature
A JWT consists of three parts, separated by dots (.), which are Base64Url-encoded:
- Header: Specifies the token type (JWT) and the signing algorithm (e.g., HMAC SHA256).
- Payload: Contains the claims (statements about an entity, like a user ID or roles).
- Signature: Used to verify the token's authenticity and ensure it hasn't been tampered with. It's created using the header, payload, and a secret key.
AuthN vs. AuthZ in the Gateway
It's crucial to distinguish between Authentication (AuthN) and Authorization (AuthZ):
- Authentication: Verifying the identity of a user or service (e.g., validating a JWT's signature and expiration).
- Authorization: Determining if an authenticated user or service has permission to perform a specific action or access a particular resource (e.g., checking user roles from JWT claims).
The Gateway can handle both, ensuring only valid and authorized requests reach your backend services.
Setting Up Gateway for JWT Security
To integrate JWT security, your Spring Cloud Gateway project typically needs the spring-cloud-starter-gateway and spring-boot-starter-security dependencies.
While spring-boot-starter-security provides a robust security framework, we'll focus on manually handling JWT validation using Gateway filters to illustrate the core concepts.
JWT Validation Flow in Gateway
When a client sends a request with a JWT, the Gateway intercepts it. The typical flow is:
- Extract Token: Get the JWT from the
Authorizationheader. - Validate Token: Verify its signature, check expiration, and ensure it's well-formed.
- Extract Claims: Parse the token to get user details and roles.
- Authorize Request: Based on claims, decide if the request can proceed to the backend service.
Implementing a Custom JWT Filter
We can implement JWT validation using a custom GlobalFilter in Spring Cloud Gateway. This filter will run for all incoming requests before they are routed.
Inside the filter, you'll access the request headers, extract the JWT, and perform your validation logic. If the token is invalid, you can reject the request directly from the Gateway.
Example: Simple JWT Filter
This example demonstrates a basic Spring Cloud Gateway application with a GlobalFilter. It logs the presence of an Authorization: Bearer header, simulating the first step of JWT validation. Run it and try accessing /test with an Authorization header!
package com.example.gateway;
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;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.http.HttpHeaders;
import reactor.core.publisher.Mono;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@SpringBootApplication
public class GatewayApplication {
public static void main(String[] args) {
SpringApplication.run(GatewayApplication.class, args);
System.out.println("Gateway started! Try accessing /test with 'Authorization' header.");
}
// Configures a dummy route for the filter to act on
@Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
return builder.routes()
.route("test_route", r -> r.path("/test")
.uri("http://httpbin.org:80/get")) // A public echo service
.build();
}
// Our simplified JWT validation filter
@Bean
public GlobalFilter jwtValidationFilter() {
Logger logger = LoggerFactory.getLogger(GatewayApplication.class);
return (exchange, chain) -> {
HttpHeaders headers = exchange.getRequest().getHeaders();
String authHeader = headers.getFirst(HttpHeaders.AUTHORIZATION);
logger.info("Intercepted request to: {}", exchange.getRequest().getURI());
if (authHeader != null && authHeader.startsWith("Bearer ")) {
String jwt = authHeader.substring(7);
logger.info("Found JWT in header: {}", jwt);
// In a real scenario, full JWT validation happens here.
// For this example, we just log it and proceed.
} else {
logger.warn("No 'Authorization: Bearer' header found.");
}
return chain.filter(exchange); // Continue to the next filter/route
};
}
}Securing Routes with Authorization
Once a JWT is validated and its claims (like user roles or scopes) are extracted, you can use these claims for authorization. Spring Cloud Gateway allows you to define authorization rules directly on your routes.
For instance, you could configure a route to only permit requests if the authenticated user has an 'ADMIN' role specified in their JWT payload.
Quick Check: JWT Authorization
After a JWT is validated by the Gateway, which of the following are key benefits of using JWTs for API authentication and authorization in a stateless microservice architecture?
Recap: Secure Gateway with JWTs
You've learned how Spring Cloud Gateway serves as a critical enforcement point for API security. We covered the basics of JWTs—their structure, benefits, and how they enable stateless authentication and authorization.
By implementing custom filters, you can integrate robust JWT validation and leverage claims to secure access to your microservices, ensuring only authorized requests reach your backend.
よくある質問
「JWT認証と認可」レッスンは無料ですか？
はい。「JWT認証と認可」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)コースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)コースには全4レッスンが含まれています。
「JWT認証と認可」で何を学びますか？
Spring Cloud GatewayにJWTベースの認証と認可を実装し、APIアクセスを保護します。 ブラウザで直接実行するハンズオンコードでAPI Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)を演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。
API Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)を始めるのに経験は必要ですか？
事前経験は必要ありません。CoddyKitのAPI Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)は初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。 これはレッスン1/4です。
「JWT認証と認可」レッスンにはどのくらい時間がかかりますか？
ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。
このAPI Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)レッスンでコードを書いて実行できますか？
はい。すべてのAPI Gateway & Reverse Proxy (Nginx + Spring Cloud Gateway)レッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。