These are basic guides to writing some custom components of the gateway.
In order to write a Route Predicate you will need to implement RoutePredicateFactory
. There is an abstract class called AbstractRoutePredicateFactory
which you can extend.
MyRoutePredicateFactory.java.
public class MyRoutePredicateFactory extends AbstractRoutePredicateFactory<HeaderRoutePredicateFactory.Config> { public MyRoutePredicateFactory() { super(Config.class); } @Override public Predicate<ServerWebExchange> apply(Config config) { // grab configuration from Config object return exchange -> { //grab the request ServerHttpRequest request = exchange.getRequest(); //take information from the request to see if it //matches configuration. return matches(config, request); }; } public static class Config { //Put the configuration properties for your filter here } }
In order to write a GatewayFilter you will need to implement GatewayFilterFactory
. There is an abstract class called AbstractGatewayFilterFactory
which you can extend.
PreGatewayFilterFactory.java.
public class PreGatewayFilterFactory extends AbstractGatewayFilterFactory<PreGatewayFilterFactory.Config> { public PreGatewayFilterFactory() { super(Config.class); } @Override public GatewayFilter apply(Config config) { // grab configuration from Config object return (exchange, chain) -> { //If you want to build a "pre" filter you need to manipulate the //request before calling chain.filter ServerHttpRequest.Builder builder = exchange.getRequest().mutate(); //use builder to manipulate the request return chain.filter(exchange.mutate().request(request).build()); }; } public static class Config { //Put the configuration properties for your filter here } }
PostGatewayFilterFactory.java.
public class PostGatewayFilterFactory extends AbstractGatewayFilterFactory<PostGatewayFilterFactory.Config> { public PostGatewayFilterFactory() { super(Config.class); } @Override public GatewayFilter apply(Config config) { // grab configuration from Config object return (exchange, chain) -> { return chain.filter(exchange).then(Mono.fromRunnable(() -> { ServerHttpResponse response = exchange.getResponse(); //Manipulate the response in some way })); }; } public static class Config { //Put the configuration properties for your filter here } }
In order to write a custom global filter, you will need to implement GlobalFilter
interface. This will apply the filter to all requests.
Example of how to set up a Global Pre and Post filter, respectively
@Bean public GlobalFilter customGlobalFilter() { return (exchange, chain) -> exchange.getPrincipal() .map(Principal::getName) .defaultIfEmpty("Default User") .map(userName -> { //adds header to proxied request exchange.getRequest().mutate().header("CUSTOM-REQUEST-HEADER", userName).build(); return exchange; }) .flatMap(chain::filter); } @Bean public GlobalFilter customGlobalPostFilter() { return (exchange, chain) -> chain.filter(exchange) .then(Mono.just(exchange)) .map(serverWebExchange -> { //adds header to response serverWebExchange.getResponse().getHeaders().set("CUSTOM-RESPONSE-HEADER", HttpStatus.OK.equals(serverWebExchange.getResponse().getStatusCode()) ? "It worked": "It did not work"); return serverWebExchange; }) .then(); }