ModifyResponseBody Filter

You can use the ModifyResponseBody filter to modify the response body before it is sent back to the client.

This filter can be configured only by using the Java DSL.

The following listing shows how to modify a response body filter:

GatewaySampleApplication.java
import static org.springframework.cloud.gateway.server.mvc.filter.AfterFilterFunctions.modifyResponseBody;
import static org.springframework.cloud.gateway.server.mvc.filter.BeforeFilterFunctions.uri;
import static org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions.route;
import static org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions.http;

@Bean
public RouterFunction<ServerResponse> gatewayRouterFunctionsModifyResponseBodySimple() {
	return route("modify_response_body")
			.GET("/anything/modifyresponsebody", http())
            .before(uri("https://example.org"))
			.after(modifyResponseBody(String.class, String.class, null,
					(request, response, s) -> s.replace("fooval", "FOOVAL")))
			.build();
}

The sample above does not change the content type or do anything dynamic. Below, the sample changes the content type and dynamically modifies the content.

GatewaySampleApplication.java
import static org.springframework.cloud.gateway.server.mvc.filter.AfterFilterFunctions.modifyResponseBody;
import static org.springframework.cloud.gateway.server.mvc.filter.BeforeFilterFunctions.uri;
import static org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions.route;
import static org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions.http;
import static org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates.host;
import org.springframework.http.MediaType;

@Configuration
class RouteConfiguration {

    @Bean
    public RouterFunction<ServerResponse> gatewayRouterFunctionsModifyResponseBody() {
        return route("modify_response_bodu")
            .route(host("*.modifyresponsebodu.org"), http())
            .before(uri("https://example.org"))
            .after(modifyResponseBody(String.class, String.class, MediaType.APPLICATION_JSON_VALUE,
                    (request, s) -> s.toUpperCase()))
            .build();
    }

}