0Pricing
Spring Boot 4 Microservices & REST APIs · Aula

Gateway de API com Spring Cloud Gateway

Configure um Spring Cloud Gateway para encaminhar requisições, aplicar filtros e proteger seus microsserviços.

Gateway de API com Spring Cloud Gateway é uma aula grátis de Spring Boot 4 Microservices & REST APIs no CoddyKit. Esta é a aula 3 de 3. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de Spring Boot 4 Microservices & REST APIs, e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de Spring Boot 4 Microservices & REST APIs inclui 3 aulas no total.

Partes desta aula ainda não foram traduzidas e aparecem em inglês.

Why an API Gateway?

Microservices are great for building scalable applications, but they can introduce complexity. Imagine having many services, each with its own address and port.

An API Gateway acts as a single, unified entry point for all client requests. It funnels incoming traffic to the correct microservice, simplifying how clients interact with your backend.

What is Spring Cloud Gateway?

Spring Cloud Gateway (SCG) is a powerful, reactive API Gateway built on Spring Framework 5, Project Reactor, and Spring Boot 2. It's designed for high performance and scalability.

  • It provides flexible routing based on requests.
  • Enables dynamic filtering of requests and responses.
  • Integrates seamlessly with other Spring Cloud projects.

Setting Up Your Gateway Project

To create a Spring Cloud Gateway application, start with a standard Spring Boot project. The key is to add the spring-cloud-starter-gateway dependency.

This dependency pulls in everything needed to transform your Spring Boot app into an intelligent gateway. Remember to include the spring-cloud-dependencies in your dependencyManagement section.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>3.2.5</version>
    <relativePath/>
  </parent>
  <groupId>com.coddykit</groupId>
  <artifactId>gateway</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>gateway</name>
  <description>Demo project for Spring Cloud Gateway</description>
  <properties>
    <java.version>17</java.version>
    <spring-cloud.version>2023.0.1</spring-cloud.version>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-gateway</artifactId>
    </dependency>
  </dependencies>
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>${spring-cloud.version}</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>
</project>

Defining Basic Routes

Routes are the core of an API Gateway. They tell the gateway how to forward incoming requests to the correct backend service. Routes are defined using predicates and a target URI.

Here, the Path=/hello/** predicate matches any request path starting with /hello/ and routes it to http://localhost:8081.

server:
  port: 8080

spring:
  application:
    name: api-gateway
  cloud:
    gateway:
      routes:
        - id: hello_route
          uri: http://localhost:8081
          predicates:
            - Path=/hello/**

Testing Your Gateway Route

To test the route, you'd typically have a backend microservice running. Let's imagine a simple 'hello-service' running on http://localhost:8081 that responds to any /hello/** path.

  • Start your Gateway application (e.g., on port 8080).
  • Make a request to http://localhost:8080/hello/world.
  • The Gateway intercepts it and forwards it to http://localhost:8081/hello/world.
  • The response from 'hello-service' is then sent back to the client via the Gateway.

Introducing Gateway Filters

Gateway Filters are functions that allow you to modify requests and responses as they pass through the gateway. They are incredibly powerful for implementing cross-cutting concerns.

  • Request Filters: Modify the request before it reaches the target service.
  • Response Filters: Modify the response before it's sent back to the client.

Filters can be applied globally to all routes or specifically to individual routes.

Applying a Simple Filter: AddRequestHeader

Let's enhance our hello_route with a filter. The AddRequestHeader filter is a built-in filter that adds a specified header to the request before forwarding it.

This is useful for injecting correlation IDs, security tokens, or origin information into requests sent to downstream services.

server:
  port: 8080

spring:
  application:
    name: api-gateway
  cloud:
    gateway:
      routes:
        - id: hello_route_with_header
          uri: http://localhost:8081
          predicates:
            - Path=/hello/**
          filters:
            - AddRequestHeader=X-Request-Source, Gateway

Centralizing Security with Gateway

An API Gateway is an ideal place to centralize security mechanisms for your microservices. Instead of implementing authentication and authorization in every service, the gateway can handle it once.

  • Authentication: Validate user credentials or tokens (e.g., JWT).
  • Authorization: Check if the authenticated user has permission for the requested resource.
  • If checks pass, the request proceeds; otherwise, it's rejected at the gateway level.

Beyond Built-in Filters: Custom Filters

While Spring Cloud Gateway provides many useful built-in filters, you might need custom logic. You can create your own filters by implementing the GlobalFilter and Ordered interfaces.

Custom filters are perfect for unique logging requirements, advanced metrics collection, or bespoke security checks that apply across your entire API landscape.

Gateway Concepts Check

Test your understanding of API Gateway fundamentals!

Recap: API Gateway Power

Great job! In this lesson, we explored the crucial role of an API Gateway in a microservices environment, specifically using Spring Cloud Gateway.

  • We understood its purpose as a single entry point.
  • Learned to configure basic routing with predicates.
  • Discovered how filters can modify requests and responses.
  • Touched upon its importance in centralizing security.

API Gateways are essential for building robust, secure, and manageable microservice systems.

Perguntas Frequentes

A aula “Gateway de API com Spring Cloud Gateway” é grátis?

Sim — o texto completo de “Gateway de API com Spring Cloud Gateway” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de Spring Boot 4 Microservices & REST APIs, atualize para CoddyKit PRO. O curso de Spring Boot 4 Microservices & REST APIs inclui 3 aulas no total.

O que vou aprender em “Gateway de API com Spring Cloud Gateway”?

Configure um Spring Cloud Gateway para encaminhar requisições, aplicar filtros e proteger seus microsserviços. Você pratica Spring Boot 4 Microservices & REST APIs com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.

Preciso ter experiência prévia para começar Spring Boot 4 Microservices & REST APIs?

Nenhuma experiência prévia é necessária. Spring Boot 4 Microservices & REST APIs no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 3 de 3.

Quanto tempo leva a aula “Gateway de API com Spring Cloud Gateway”?

A maioria das aulas CoddyKit leva cerca de 5–10 minutos. Cada uma é compacta e interativa, então você faz progresso constante e retoma exatamente de onde parou entre web e app.

Posso escrever e executar código nesta aula de Spring Boot 4 Microservices & REST APIs?

Sim. Cada aula de Spring Boot 4 Microservices & REST APIs inclui um editor de código integrado, então você escreve e executa código real direto no navegador e recebe feedback de IA instantaneamente — nenhuma configuração local necessária.

Todas as aulas deste curso

  1. Implementando a descoberta de serviços com Eureka
  2. Balanceamento de carga no cliente com Ribbon
  3. Gateway de API com Spring Cloud Gateway
← Voltar para Spring Boot 4 Microservices & REST APIs