Changes to Spring Cloud Gateway leaving the incubator

The article directories

1. I. Overview of Spring Cloud Gateway
   1. 1.1 What is Spring Cloud GateWay
   2. 1.2 Functions of Spring Cloud GateWay
   3. 1.3 Spring Cloud GateWay leaves the incubator
   4. 1.3 Build the Gateway with Spring MVC
      1. 1.3.1 How to Include Spring Cloud Gateway
      2. 1.3.2 Building a Gateway Using Spring MVC
2. 2.Spring Cloud Gateway MVC module source code analysis
   1. 2.1 Build the Demo of Spring Cloud Gateway
   2. 2.2 Spring Cloud Gateway module source code analysis
   3. 2.3 Code Analysis

Abstract: After The encapsulation of Netflix’s Zuul by Spring Cloud, Spring Cloud Zuul has been used as the gateway of Spring Cloud. The API Gateway is Dead! Long Live the API Gateway! Zuul, Zuul 2, and why Spring Cloud Gateway is available. This article will conduct a demo and brief analysis of the spring-Cloud-gateway-MVC source code.

I. Overview of Spring Cloud Gateway

1.1 What is Spring Cloud GateWay

1.2 Functions of Spring Cloud GateWay

1.3 Spring Cloud GateWay leaves the incubator

Since December 2016, there has been a Spring Cloud Gateway project on Github at the following address:Github.com/spring-clou…, as shown in the figure below.

1.3 Build the Gateway with Spring MVC

1.3.1 How to Include Spring Cloud Gateway

1.3.2 Building a Gateway Using Spring MVC

Spring Cloud Gateway provides a utility object called ProxyExchange which you can use inside a regular Spring MVC handler as a method parameter. It supports basic downstream HTTP exchanges via methods that mirror the HTTP verbs, or forwarding to a local handler via the forward() method.

Example (proxying a request to “/test” downstream to a remote server):

 @RestController
@SpringBootApplication
public class GatewaySampleApplication {
	@Value("${remote.home}")
	private URI home;
	@GetMapping("/test")
	public ResponseEntity<?> proxy(ProxyExchange<Object> proxy) throws Exception {
		return proxy.uri(home.toString() + "/image/png").get();
	}
}Copy the code

The Spring Cloud Gateway provides a utility object called ProxyExchange that you can use to forward and redirect the build Gateway in the same way that you use the Spring MVC Handler.

For more information :github.com/spring-clou…

2.Spring Cloud Gateway MVC module source code analysis

2.1 Build the Demo of Spring Cloud Gateway

The project of Spring Cloud Gateway has provided me with a project of Spring-cloud-gateway-sample. This project relies on spring-cloud-gateway-MVC, so I need to analyze its source code. Just make sample work normally and it will be ok.

2.2 Spring Cloud Gateway module source code analysis

1. In spring-cloud-gateway-sample, add the application name and port configuration to application.yml

server: port: 8080 spring: application: name: sc-gw management: security: enabled: false remote: home: http://httpbin.org # Request forwarding target service UrlCopy the code

2.org.springframework.cloud.gateway.sample.GatewaySampleApplication.java

@RestController @SpringBootApplication public class GatewaySampleApplication { @Value("${remote.home}") private URI home; // @getMapping (path="/test") {// head ="/test"; headers="x-host=png.abc.org") public ResponseEntity<Object> proxy(ProxyExchange<Object> proxy) throws Exception { return  proxy.uri(home.toString() + "/image/png") .get(header("X-TestHeader", "foobar")); } @GetMapping("/test2") public ResponseEntity<Object> proxyFoos(ProxyExchange<Object> proxy) throws Exception { return proxy.uri(home.toString() + "/image/webp").get(header("X-AnotherHeader", "baz")); } private Function<ResponseEntity<Object>, ResponseEntity<Object>> header(String key, String value) { return response -> ResponseEntity.status(response.getStatusCode()) .headers(response.getHeaders()).header(key, value) .body(response.getBody()); } public static void main(String[] args) { SpringApplication.run(GatewaySampleApplication.class, args); }}Copy the code

2.3 Code Analysis

@GetMapping("/test2")
public ResponseEntity<Object> proxyFoos(ProxyExchange<Object> proxy) throws Exception {
	return proxy.uri(home.toString() + "/image/webp").get(header("X-AnotherHeader", "baz"));
}Copy the code

Public ProxyExchange < T > uri (String uri) {try {/ / will uri:http://httpbin.org/image/webp, The new URI object returns this. URI = new URI(URI); } catch (URISyntaxException e) { throw new IllegalStateException("Cannot create URI", e); } return this; }Copy the code

@Override
public <T> T execute(URI url, HttpMethod method, RequestCallback requestCallback,
		ResponseExtractor<T> responseExtractor) throws RestClientException {
	return doExecute(url, method, requestCallback, responseExtractor);
}Copy the code