you can extract/read/modify/manipulate the request and response and their headers with the help of ServerHttpRequestDecorator & ServerHttpResponseDecorator see below
Note: i implemented GatewayFilter because i have this logic in gateway service level, if you want to modify at micro service level you can use WebFilter
import lombok.extern.log4j.Log4j2;
import org.apache.commons.io.IOUtils;
import org.reactivestreams.Publisher;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DefaultDataBuffer;
import org.springframework.core.io.buffer.DefaultDataBufferFactory;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import reactor.core.scheduler.Schedulers;
import java.io.ByteArrayOutputStream;
import java.nio.channels.Channels;
import java.nio.charset.StandardCharsets;
@Configuration
@Log4j2
public class RequestResponseModifyFilter implements GatewayFilter/WebFilter, Ordered {
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
String path = exchange.getRequest().getPath().toString();
ServerHttpResponse response = exchange.getResponse();
ServerHttpRequest request = exchange.getRequest();
DataBufferFactory dataBufferFactory = response.bufferFactory();
// log the request body
ServerHttpRequest decoratedRequest = getDecoratedRequest(request);
// log the response body
ServerHttpResponseDecorator decoratedResponse = getDecoratedResponse(path, response, request, dataBufferFactory);
return chain.filter(exchange.mutate().request(decoratedRequest).response(decoratedResponse).build());
}
private ServerHttpResponseDecorator getDecoratedResponse(String path, ServerHttpResponse response, ServerHttpRequest request, DataBufferFactory dataBufferFactory) {
return new ServerHttpResponseDecorator(response) {
@Override
public Mono<Void> writeWith(final Publisher<? extends DataBuffer> body) {
if (body instanceof Flux) {
Flux<? extends DataBuffer> fluxBody = (Flux<? extends DataBuffer>) body;
return super.writeWith(fluxBody.buffer().map(dataBuffers -> {
DefaultDataBuffer joinedBuffers = new DefaultDataBufferFactory().join(dataBuffers);
byte[] content = new byte[joinedBuffers.readableByteCount()];
joinedBuffers.read(content);
String responseBody = new String(content, StandardCharsets.UTF_8);//MODIFY RESPONSE and Return the Modified response
log.debug("requestId: {}, method: {}, url: {}, \nresponse body :{}", request.getId(), request.getMethodValue(), request.getURI(), responseBody);
return dataBufferFactory.wrap(responseBody.getBytes());
})).onErrorResume(err -> {
log.error("error while decorating Response: {}",err.getMessage());
return Mono.empty();
});
}
return super.writeWith(body);
}
};
}
private ServerHttpRequest getDecoratedRequest(ServerHttpRequest request) {
return new ServerHttpRequestDecorator(request) {
@Override
public Flux<DataBuffer> getBody() {
log.debug("requestId: {}, method: {} , url: {}", request.getId(), request.getMethodValue(), request.getURI());
return super.getBody().publishOn(Schedulers.boundedElastic()).doOnNext(dataBuffer -> {
try (ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream()) {
Channels.newChannel(byteArrayOutputStream).write(dataBuffer.asByteBuffer().asReadOnlyBuffer());
String requestBody = IOUtils.toString(byteArrayOutputStream.toByteArray(), StandardCharsets.UTF_8.toString());//MODIFY REQUEST and Return the Modified request
log.debug("for requestId: {}, request body :{}", request.getId(), requestBody);
} catch (Exception e) {
log.error(e.getMessage());
}
});
}
};
}
@Override
public int getOrder() { return -2;}
}
