Spring Cloud Gateway-ServerWebExchange Core Methods and Request or Response Content Modification

Prerequisites

This article was written using Spring Cloud Gateway version Greenwich.SR1.

When we use Spring Cloud Gateway, we notice that the filters (including GatewayFilter, GlobalFilter and the filter chain GatewayFilterChain), all depend on the ServerWebExchange.

public interface GlobalFilter {

    Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain);
}

public interface GatewayFilter extends ShortcutConfigurable {

	Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain);
}

public interface GatewayFilterChain {

    Mono<Void> filter(ServerWebExchange exchange);
}

The design here is similar to Filter in Servlet, the current filter can decide whether to execute the logic of the next filter by GatewayFilterChain#filter() is called or not to decide. And ServerWebExchange is equivalent to the context of the current request and response. The ServerWebExchange instance not only stores the Request and Response objects, but also provides some extension methods, so if you want to implement the transformation of the request parameters or response parameters, you must have a deeper understanding of the ServerWebExchange.

Understanding ServerWebExchange

First, look at the annotation of ServerWebExchange.

Contract for an HTTP request-response interaction. Provides access to the HTTP request and response and also exposes additional server-side processing related properties and features such as request attributes.

In fact, the ServerWebExchange named Service Web Exchange holds important request-response attributes, request instances and response instances, etc., somewhat like the role of Context.

ServerWebExchange Interface

All methods of the ServerWebExchange interface.

public interface ServerWebExchange {

    // KEY of the log prefix property, with the value org.springframework.web.server.ServerWebExchange.LOG_ID
    // 可to be understood as attributes.set("org.springframework.web.server.ServerWebExchange.LOG_ID", "specific value of log prefix");
    // The effect is to print the logs will be spliced this KEY to drink the prefix value, the default value is ""
    String LOG_ID_ATTRIBUTE = ServerWebExchange.class.getName() + ".LOG_ID";
    String getLogPrefix();

    // Get ServerHttpRequest object
    ServerHttpRequest getRequest();

    // Get ServerHttpResponse object
    ServerHttpResponse getResponse();
    
    // Returns the requested property of the current exchange, the result is a variable Map
    Map<String, Object> getAttributes();
    
    // Get request properties based on KEY
    @Nullable
    default <T> T getAttribute(String name) {
        return (T) getAttributes().get(name);
    }
    
    // Get request attributes based on KEY, made non-empty judgment
    @SuppressWarnings("unchecked")
    default <T> T getRequiredAttribute(String name) {
        T value = getAttribute(name);
        Assert.notNull(value, () -> "Required attribute '" + name + "' is missing");
        return value;
    }

     // Get request properties based on KEY, need to provide default values
    @SuppressWarnings("unchecked")
    default <T> T getAttributeOrDefault(String name, T defaultValue) {
        return (T) getAttributes().getOrDefault(name, defaultValue);
    } 

    // Returns the current requested network session
    Mono<WebSession> getSession();

    // Returns the currently requested authenticated user, if one exists
    <T extends Principal> Mono<T> getPrincipal();  
    
    // Return the requested form data or an empty Map, only when the Content-Type is application/x-www-form-urlencoded this method will return a non-empty Map -- this is generally used for form data submission
    Mono<MultiValueMap<String, String>> getFormData();   
    
    // Return the part data of multipart request or an empty Map, only when Content-Type is multipart/form-data this method will return a non-empty Map -- this is generally used for file uploads
    Mono<MultiValueMap<String, Part>> getMultipartData();
    
    // Return the Spring context
    @Nullable
    ApplicationContext getApplicationContext();   

    // These methods are related to the lastModified property
    boolean isNotModified();
    boolean checkNotModified(Instant lastModified);
    boolean checkNotModified(String etag);
    boolean checkNotModified(@Nullable String etag, Instant lastModified);
    
    // URL conversion
    String transformUrl(String url);    
   
    // URL Conversion Mapping
    void addUrlTransformer(Function<String, String> transformer); 

    // Note this method, the method name is: change, this is a method to modify the properties of ServerWebExchange, the return is a Builder instance, Builder is the internal class of ServerWebExchange
    default Builder mutate() {
	     return new DefaultServerWebExchangeBuilder(this);
    }

    interface Builder {      
         
        // Override ServerHttpRequest
        Builder request(Consumer<ServerHttpRequest.Builder> requestBuilderConsumer);
        Builder request(ServerHttpRequest request);
        
        // Override ServerHttpResponse
        Builder response(ServerHttpResponse response);
        
        // Override the currently requested authenticated user
        Builder principal(Mono<Principal> principalMono);
    
        // Building a new ServerWebExchange instance
        ServerWebExchange build();
    }
}

Noting the ServerWebExchange#mutate() method, the ServerWebExchange instance can be understood as an immutable instance, and if we want to modify it, we need to generate a new instance by the mutate() method, such as this.

public class CustomGlobalFilter implements GlobalFilter {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        // Here you can modify the ServerHttpRequest instance
        ServerHttpRequest newRequest = ...
        ServerHttpResponse response = exchange.getResponse();
        // Here you can modify the ServerHttpResponse instance
        ServerHttpResponse newResponse = ...
        // Building a new ServerWebExchange instance
        ServerWebExchange newExchange = exchange.mutate().request(newRequest).response(newResponse).build();
        return chain.filter(newExchange);
    }
}

ServerHttpRequest interface

The ServerHttpRequest instance is used to host the request related properties and request body, the underlying Spring Cloud Gateway uses Netty to handle the network request, by tracing the source code, you can learn from the ReactorHttpHandlerAdapter that the specific implementation of the ServerHttpRequest instance held in the Spring Cloud Gateway is ReactorServerHttpRequest. The specific implementation of the ServerHttpRequest instance held in the ServerWebExchange instance is ReactorServerHttpRequest. The reason for listing the relationship between these instances is that it is easier to sort out some implicit issues, such as

The initialization of the internal property headers in the parent class AbstractServerHttpRequest of ReactorServerHttpRequest encapsulates the requested HTTP headers as a read-only instance of.

public AbstractServerHttpRequest(URI uri, @Nullable String contextPath, HttpHeaders headers) {
    this.uri = uri;
    this.path = RequestPath.parse(uri, contextPath);
    this.headers = HttpHeaders.readOnlyHttpHeaders(headers);
}

// HttpHeaders类中的readOnlyHttpHeaders方法，其中ReadOnlyHttpHeaders屏蔽了所有修改请求头的方法，直接抛出UnsupportedOperationException
public static HttpHeaders readOnlyHttpHeaders(HttpHeaders headers) {
    Assert.notNull(headers, "HttpHeaders must not be null");
    if (headers instanceof ReadOnlyHttpHeaders) {
        return headers;
    }
    else {
        return new ReadOnlyHttpHeaders(headers);
    }
}

So you can’t get the request header HttpHeaders instance directly from the ServerHttpRequest instance and modify it.

The ServerHttpRequest interface is as follows.

public interface HttpMessage {
    
    // Get the request headers, the current implementation returns an instance of ReadOnlyHttpHeaders, read-only
    HttpHeaders getHeaders();
}    

public interface ReactiveHttpInputMessage extends HttpMessage {
    
    // Return the Flux wrapper for the request body
    Flux<DataBuffer> getBody();
}

public interface HttpRequest extends HttpMessage {

    // Return HTTP request method, resolve to HttpMethod instance
    @Nullable
    default HttpMethod getMethod() {
        return HttpMethod.resolve(getMethodValue());
    }
    
    // Returns the HTTP request method, string
    String getMethodValue();    
    
    // Requested URI
    URI getURI();
}    

public interface ServerHttpRequest extends HttpRequest, ReactiveHttpInputMessage {
    
    // Unique identification of the connection or for logging purposes
    String getId();   
    
    // Get the request path, encapsulated as RequestPath object
    RequestPath getPath();
    
    // Returns query parameters, which are read-only MultiValueMap instances
    MultiValueMap<String, String> getQueryParams();

    // Returns a collection of cookies, which is a read-only MultiValueMap instance
    MultiValueMap<String, HttpCookie> getCookies();  
    
    // Remote server address information
    @Nullable
    default InetSocketAddress getRemoteAddress() {
       return null;
    }

    // Information about SSL session implementation
    @Nullable
    default SslInfo getSslInfo() {
       return null;
    }  
    
    // Modifies the requested method, returning a builder instance Builder, which is an internal class
    default ServerHttpRequest.Builder mutate() {
        return new DefaultServerHttpRequestBuilder(this);
    } 

    interface Builder {

        // Override request method
        Builder method(HttpMethod httpMethod);
		 
        // Override the request's URI, request path or context, all three of which have a constraining relationship with each other, as described in the API comments
        Builder uri(URI uri);
        Builder path(String path);
        Builder contextPath(String contextPath);

        // Override request header
        Builder header(String key, String value);
        Builder headers(Consumer<HttpHeaders> headersConsumer);
        
        // Override SslInfo
        Builder sslInfo(SslInfo sslInfo);
        
        // Build a new ServerHttpRequest instance
        ServerHttpRequest build();
    }         
}

If you want to modify the ServerHttpRequest instance, then you need to do this.

1
2

ServerHttpRequest request = exchange.getRequest();
ServerHttpRequest newRequest = request.mutate().headers("key","value").path("/myPath").build();

The most noteworthy thing here is: ServerHttpRequest or HttpMessage interface provides a method to get the request headers HttpHeaders getHeaders(); returns a read-only instance, specifically of type ReadOnlyHttpHeaders, mentioned here more than once I wrote this blog post using Spring Cloud Gateway version Greenwich.SR1.

ServerHttpResponse interface

The ServerHttpResponse instance is used to carry the response-related properties and response body, the underlying Spring Cloud Gateway uses Netty to handle network requests, by tracing the source code, you can learn from the ReactorHttpHandlerAdapter that the specific implementation of the ServerHttpResponse instance held in the Spring Cloud Gateway is ReactorServerHttpResponse. ServerWebExchange instance held in the ServerHttpResponse instance of the specific implementation is ReactorServerHttpResponse. The reason for listing the relationships between these instances is that it is easier to sort out some of the implicit issues, such as

// Parent class of ReactorServerHttpResponse
public AbstractServerHttpResponse(DataBufferFactory dataBufferFactory, HttpHeaders headers) {
	Assert.notNull(dataBufferFactory, "DataBufferFactory must not be null");
	Assert.notNull(headers, "HttpHeaders must not be null");
	this.dataBufferFactory = dataBufferFactory;
	this.headers = headers;
	this.cookies = new LinkedMultiValueMap<>();
}

public ReactorServerHttpResponse(HttpServerResponse response, DataBufferFactory bufferFactory) {
	super(bufferFactory, new HttpHeaders(new NettyHeadersAdapter(response.responseHeaders())));
	Assert.notNull(response, "HttpServerResponse must not be null");
	this.response = response;
}

It is known that ReactorServerHttpResponse constructor to initialize the instance, the storage response Header is HttpHeaders instance, that is, the response Header can be directly modified.

ServerHttpResponse interface is as follows.

public interface HttpMessage {
    
    // Get the response Header, the current implementation returns an instance of HttpHeaders, which can be modified directly
    HttpHeaders getHeaders();
}  

public interface ReactiveHttpOutputMessage extends HttpMessage {
    
    // Get DataBufferFactory instance for wrapping or generating data buffer DataBuffer instance (create response body)
    DataBufferFactory bufferFactory();

    // Register an action that will be called back before the HttpOutputMessage is submitted
    void beforeCommit(Supplier<? extends Mono<Void>> action);

    // Determine if the HttpOutputMessage has been submitted
    boolean isCommitted();
    
    // Write the message body to the HTTP protocol layer
    Mono<Void> writeWith(Publisher<? extends DataBuffer> body);

    // Write the message body to the HTTP protocol layer and flush the buffer
    Mono<Void> writeAndFlushWith(Publisher<? extends Publisher<? extends DataBuffer>> body);
    
    // Indicates that the message processing has ended, generally this method is called automatically at the end of the message processing, multiple calls will not produce side effects
    Mono<Void> setComplete();
}

public interface ServerHttpResponse extends ReactiveHttpOutputMessage {
    
    // Set the response status code
    boolean setStatusCode(@Nullable HttpStatus status);
    
    // Get the response status code
    @Nullable
    HttpStatus getStatusCode();
    
    // Get response cookie, encapsulated as MultiValueMap instance, can be modified
    MultiValueMap<String, ResponseCookie> getCookies();  
    
    // Adding response cookies
    void addCookie(ResponseCookie cookie);  
}

Here you can see that all the properties are mutable except for the response body which is harder to modify.

ServerWebExchangeUtils and Context Properties

ServerWebExchangeUtils holds a lot of static public string KEY values inside (the actual values of these string KEYs are org.springframework.cloud.gateway.support.ServerWebExchangeUtils. + any static public KEY below), these string KEY values are generally used for ServerWebExchange attributes (Attribute, see ServerWebExchange#getAttributes() method above) KEY, these attribute values have a special meaning, in the use of filters If the timing is appropriate, you can directly take out the use of the following analysis one by one.

PRESERVE_HOST_HEADER_ATTRIBUTE : whether to save the Host attribute, the value is a boolean type, the write location is PreserveHostHeaderGatewayFilterFactory, the location used is NettyRoutingFilter , the effect is that if set to true, the Host property in the HTTP request header will be written to the underlying Reactor-Netty’s request Header property.
CLIENT_RESPONSE_ATTR : Holds the underlying Reactor-Netty response object of type reactor.netty.http.client.HttpClientResponse.
CLIENT_RESPONSE_CONN_ATTR : Holds the underlying Reactor-Netty connection object, of type reactor.netty.Connection.
URI_TEMPLATE_VARIABLES_ATTRIBUTE : After PathRoutePredicateFactory finishes parsing the path parameters, it stores the parsed placeholder KEY-PathPath mapping in the ServerWebExchange property, KEY is URI_TEMPLATE_VARIABLES_ATTRIBUTE.
CLIENT_RESPONSE_HEADER_NAMES : Holds the set of names of the underlying Reactor-Netty’s response Header.
GATEWAY_ROUTE_ATTR : Holds the specific route matched in RoutePredicateHandlerMapping ( org.springframework.cloud.gateway.route.Route ) instance, through which the route instance to know which downstream service the current request will be routed to.
GATEWAY_REQUEST_URL_ATTR : ( java.net.URI type instance), this instance represents the real URI that needs to be requested to the downstream service after direct request or load balancing processing.
GATEWAY_ORIGINAL_REQUEST_URL_ATTR : (instance of type java.net.URI), this instance represents the original request URI that needs to be saved when the request URI is rewritten.
GATEWAY_HANDLER_MAPPER_ATTR: Short name of the type of the specific instance of HandlerMapping currently in use (usually the string “RoutePredicateHandlerMapping”).
GATEWAY_SCHEME_PREFIX_ATTR : Determines that the schemeSpecificPart attribute, if present in the target route URI, holds the scheme of the URI in which the route URI will be reconstructed, see RouteToRequestUrlFilter.
GATEWAY_PREDICATE_ROUTE_ATTR: Used to hold the ID of the specific route matched in RoutePredicateHandlerMapping ( org.springframework.cloud.gateway.route. ) instance’s ID.
WEIGHT_ATTR : experimental function (not recommended for official use in this version yet) to store group weight related properties, see WeightCalculatorWebFilter.
ORIGINAL_RESPONSE_CONTENT_TYPE_ATTR : Holds the value of the ContentType in the response Header.
HYSTRIX_EXECUTION_EXCEPTION_ATTR : An instance of Throwable, which holds the exception instance when Hystrix executes an exception, see HystrixGatewayFilterFactory .
GATEWAY_ALREADY_ROUTED_ATTR : Boolean value to determine if routing has been performed, see NettyRoutingFilter .
GATEWAY_ALREADY_PREFIXED_ATTR : Boolean to determine if a prefix has been added to the request path, see PrefixPathGatewayFilterFactory .

The contextual properties provided by ServerWebExchangeUtils are used for the secure transfer and use of some important internal instances or identity properties when the ServerWebExchange component of Spring Cloud Gateway is processing requests and responses, there may be some risk in using them as no No one can be sure whether the original attributes KEY or VALUE will change after a version upgrade, so if you have assessed the risk or avoided it, you can use them without fear. For example, when we do request and response logging (similar to Nginx’s Access Log), we can rely on GATEWAY_ROUTE_ATTR, because we want to print information about the destination of the route. As a simple example.

@Slf4j
@Component
public class AccessLogFilter implements GlobalFilter {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        String path = request.getPath().pathWithinApplication().value();
        HttpMethod method = request.getMethod();
        // Get the destination URI of the route
        URI targetUri = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
        InetSocketAddress remoteAddress = request.getRemoteAddress();
        return chain.filter(exchange.mutate().build()).then(Mono.fromRunnable(() -> {
            ServerHttpResponse response = exchange.getResponse();
            HttpStatus statusCode = response.getStatusCode();
            log.info("request path:{},client remote IP address:{},request method:{},target URI:{},response code:{}",
                    path, remoteAddress, method, targetUri, statusCode);
        }));
    }
}

Modify request body

Modifying the request body is a relatively common requirement. For example, when we implement a gateway using Spring Cloud Gateway, we have to implement a feature: parse the JWT stored in the request header, extract the userId from it, and write it to the request body. Let’s simplify this scenario by assuming that we store the userId explicitly in the accessToken in the request header and the request body is a JSON structure.

{
    "serialNumber": "",
    "payload" : {
        // ... Here is the payload, which holds the specific data
    }
}

We need to extract the accessToken, which is the userId, and insert it into the request body JSON as follows.

{
    "userId": "userId",
    "serialNumber": "",
    "payload" : {
        // ... Here is the payload, which holds the specific data
    }
}

Here, to simplify the design, the global filter GlobalFilter is used to implement the actual need to consider in conjunction with specific scenarios.

@Slf4j
@Component
public class ModifyRequestBodyGlobalFilter implements GlobalFilter {

    private final DataBufferFactory dataBufferFactory = new NettyDataBufferFactory(ByteBufAllocator.DEFAULT);

    @Autowired
    private ObjectMapper objectMapper;

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        String accessToken = request.getHeaders().getFirst("accessToken");
        if (!StringUtils.hasLength(accessToken)) {
            throw new IllegalArgumentException("accessToken");
        }
        // Create a new ServerHttpRequest decorator, overriding the methods that need to be decorated
        ServerHttpRequestDecorator decorator = new ServerHttpRequestDecorator(request) {

            @Override
            public Flux<DataBuffer> getBody() {
                Flux<DataBuffer> body = super.getBody();
                InputStreamHolder holder = new InputStreamHolder();
                body.subscribe(buffer -> holder.inputStream = buffer.asInputStream());
                if (null != holder.inputStream) {
                    try {
                        // Parsing JSON nodes
                        JsonNode jsonNode = objectMapper.readTree(holder.inputStream);
                        Assert.isTrue(jsonNode instanceof ObjectNode, "JSON format exceptions");
                        ObjectNode objectNode = (ObjectNode) jsonNode;
                        // The outermost JSON node writes a new attribute
                        objectNode.put("userId", accessToken);
                        DataBuffer dataBuffer = dataBufferFactory.allocateBuffer();
                        String json = objectNode.toString();
                        log.info("The final JSON data is:{}", json);
                        dataBuffer.write(json.getBytes(StandardCharsets.UTF_8));
                        return Flux.just(dataBuffer);
                    } catch (Exception e) {
                        throw new IllegalStateException(e);
                    }
                } else {
                    return super.getBody();
                }
            }
        };
        // Regenerate a new ServerWebExchange using the modified ServerHttpRequestDecorator
        return chain.filter(exchange.mutate().request(decorator).build());
    }

    private class InputStreamHolder {

        InputStream inputStream;
    }
}

To test.

// HTTP
POST /order/json HTTP/1.1
Host: localhost:9090
Content-Type: application/json
accessToken: 10086
Accept: */*
Cache-Control: no-cache
Host: localhost:9090
accept-encoding: gzip, deflate
content-length: 94
Connection: keep-alive
cache-control: no-cache

{
    "serialNumber": "1",
    "payload": {
        "name": "doge"
    }
}

// Log output
The final JSON data is:{"serialNumber":"1","payload":{"name":"doge"},"userId":"10086"}

The most important thing is the use of ServerHttpRequest decorator ServerHttpRequestDecorator, mainly covering the methods corresponding to the request body data buffer can be, as for how to handle other logic need to consider themselves, here is just a simple demonstration. The general code logic is as follows.

ServerHttpRequest request = exchange.getRequest();
ServerHttpRequestDecorator requestDecorator = new ServerHttpRequestDecorator(request) {

     @Override
     public Flux<DataBuffer> getBody() {
         // Get the Flux that carries the original request body
         Flux<DataBuffer> body = super.getBody();
         // Here the new Flux that carries the request body is generated in a custom way
         Flux<DataBuffer> newBody = ...
         return newBody;
     }            
}
return chain.filter(exchange.mutate().request(requestDecorator).build());

Modify response body

The requirement of modifying the response body is also relatively common, and the specific approach is similar to modifying the request body. For example, we want to achieve the following function: the third-party service request passes through the gateway, the original message is ciphertext, we need to decrypt the ciphertext at the gateway, and then route the decrypted plaintext to the downstream service, the downstream service processes the plaintext successfully, and needs to encrypt the plaintext into ciphertext at the gateway before returning to the third-party service. Now we simplify the whole process by using AES encryption algorithm and unifying the password as the string “throwable”, assuming that the request and response messages are as follows.

// Request ciphertext
{
    "serialNumber": "",
    "payload" : "Encrypted request message load"
}

// Request plaintext (as a hint only)s
{
    "serialNumber": "",
    "payload" : "{\"name:\":\"doge\"}"
}

// Response ciphertext
{
    "code": 200,
    "message":"ok",
    "payload" : "Encrypted response message load"
}

// Responding to plain text (as a hint only)
{
    "code": 200,
    "message":"ok",
    "payload" : "{\"name:\":\"doge\",\"age\":26}"
}

To facilitate some encryption/decryption or encoding/decoding implementations, the commons-codec class library of Apache needs to be introduced.

<dependency>
    <groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
    <version>1.12</version>
</dependency>

A global filter is defined here specifically to handle encryption and decryption, and it is actually best to combine this with a real scenario to decide if a global filter is appropriate, here is just an example.

// AES encryption and decryption tools class
public enum AesUtils {

    // Single instance
    X;

    private static final String PASSWORD = "throwable";
    private static final String KEY_ALGORITHM = "AES";
    private static final String SECURE_RANDOM_ALGORITHM = "SHA1PRNG";
    private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";

    public String encrypt(String content) {
        try {
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, provideSecretKey());
            return Hex.encodeHexString(cipher.doFinal(content.getBytes(StandardCharsets.UTF_8)));
        } catch (Exception e) {
            throw new IllegalArgumentException(e);
        }
    }

    public byte[] decrypt(String content) {
        try {
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, provideSecretKey());
            return cipher.doFinal(Hex.decodeHex(content));
        } catch (Exception e) {
            throw new IllegalArgumentException(e);
        }
    }

    private SecretKey provideSecretKey() {
        try {
            KeyGenerator keyGen = KeyGenerator.getInstance(KEY_ALGORITHM);
            SecureRandom secureRandom = SecureRandom.getInstance(SECURE_RANDOM_ALGORITHM);
            secureRandom.setSeed(PASSWORD.getBytes(StandardCharsets.UTF_8));
            keyGen.init(128, secureRandom);
            return new SecretKeySpec(keyGen.generateKey().getEncoded(), KEY_ALGORITHM);
        } catch (Exception e) {
            throw new IllegalArgumentException(e);
        }
    }
}

// EncryptionGlobalFilter
@Slf4j
@Component
public class EncryptionGlobalFilter implements GlobalFilter, Ordered {

    @Autowired
    private ObjectMapper objectMapper;

    @Override
    public int getOrder() {
        return -2;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpRequest request = exchange.getRequest();
        ServerHttpResponse response = exchange.getResponse();
        DataBufferFactory bufferFactory = exchange.getResponse().bufferFactory();
        ServerHttpRequestDecorator requestDecorator = processRequest(request, bufferFactory);
        ServerHttpResponseDecorator responseDecorator = processResponse(response, bufferFactory);
        return chain.filter(exchange.mutate().request(requestDecorator).response(responseDecorator).build());
    }

    private ServerHttpRequestDecorator processRequest(ServerHttpRequest request, DataBufferFactory bufferFactory) {
        Flux<DataBuffer> body = request.getBody();
        DataBufferHolder holder = new DataBufferHolder();
        body.subscribe(dataBuffer -> {
            int len = dataBuffer.readableByteCount();
            holder.length = len;
            byte[] bytes = new byte[len];
            dataBuffer.read(bytes);
            DataBufferUtils.release(dataBuffer);
            String text = new String(bytes, StandardCharsets.UTF_8);
            JsonNode jsonNode = readNode(text);
            JsonNode payload = jsonNode.get("payload");
            String payloadText = payload.asText();
            byte[] content = AesUtils.X.decrypt(payloadText);
            String requestBody = new String(content, StandardCharsets.UTF_8);
            log.info("Modify request body payload,before:{},after:{}", payloadText, requestBody);
            rewritePayloadNode(requestBody, jsonNode);
            DataBuffer data = bufferFactory.allocateBuffer();
            data.write(jsonNode.toString().getBytes(StandardCharsets.UTF_8));
            holder.dataBuffer = data;
        });
        HttpHeaders headers = new HttpHeaders();
        headers.putAll(request.getHeaders());
        headers.remove(HttpHeaders.CONTENT_LENGTH);
        return new ServerHttpRequestDecorator(request) {

            @Override
            public HttpHeaders getHeaders() {
                int contentLength = holder.length;
                if (contentLength > 0) {
                    headers.setContentLength(contentLength);
                } else {
                    headers.set(HttpHeaders.TRANSFER_ENCODING, "chunked");
                }
                return headers;
            }

            @Override
            public Flux<DataBuffer> getBody() {
                return Flux.just(holder.dataBuffer);
            }
        };
    }

    private ServerHttpResponseDecorator processResponse(ServerHttpResponse response, DataBufferFactory bufferFactory) {
        return new ServerHttpResponseDecorator(response) {

            @SuppressWarnings("unchecked")
            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                if (body instanceof Flux) {
                    Flux<? extends DataBuffer> flux = (Flux<? extends DataBuffer>) body;
                    return super.writeWith(flux.map(buffer -> {
                        CharBuffer charBuffer = StandardCharsets.UTF_8.decode(buffer.asByteBuffer());
                        DataBufferUtils.release(buffer);
                        JsonNode jsonNode = readNode(charBuffer.toString());
                        JsonNode payload = jsonNode.get("payload");
                        String text = payload.toString();
                        String content = AesUtils.X.encrypt(text);
                        log.info("Modify the response body payload, before modification:{},after modification:{}", text, content);
                        setPayloadTextNode(content, jsonNode);
                        return bufferFactory.wrap(jsonNode.toString().getBytes(StandardCharsets.UTF_8));
                    }));
                }
                return super.writeWith(body);
            }
        };
    }

    private void rewritePayloadNode(String text, JsonNode root) {
        try {
            JsonNode node = objectMapper.readTree(text);
            ObjectNode objectNode = (ObjectNode) root;
            objectNode.set("payload", node);
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }

    private void setPayloadTextNode(String text, JsonNode root) {
        try {
            ObjectNode objectNode = (ObjectNode) root;
            objectNode.set("payload", new TextNode(text));
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }

    private JsonNode readNode(String in) {
        try {
            return objectMapper.readTree(in);
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }

    private class DataBufferHolder {

        DataBuffer dataBuffer;
        int length;
    }
}

Prepare a ciphertext first.

Map<String, Object> json = new HashMap<>(8);
json.put("serialNumber", "请求流水号");
String content = "{\"name\": \"doge\"}";
json.put("payload", AesUtils.X.encrypt(content));
System.out.println(new ObjectMapper().writeValueAsString(json));

// Output
{"serialNumber":"请求流水号","payload":"144e3dc734743f5709f1adf857bca473da683246fd612f86ac70edeb5f2d2729"}

Simulation request.

POST /order/json HTTP/1.1
Host: localhost:9090
accessToken: 10086
Content-Type: application/json
User-Agent: PostmanRuntime/7.13.0
Accept: */*
Cache-Control: no-cache
Postman-Token: bda07fc3-ea1a-478c-b4d7-754fe6f37200,634734d9-feed-4fc9-ba20-7618bd986e1c
Host: localhost:9090
cookie: customCookieName=customCookieValue
accept-encoding: gzip, deflate
content-length: 104
Connection: keep-alive
cache-control: no-cache

{
    "serialNumber": "请求流水号",
    "payload": "FE49xzR0P1cJ8a34V7ykc9poMkb9YS+GrHDt618tJyk="
}

// Response Results
{
    "serialNumber": "请求流水号",
    "payload": "oo/K1igg2t/S8EExkBVGWOfI1gAh5pBpZ0wyjNPW6e8="   # <--- After decryption：{"name":"doge","age":26}
}

Problems encountered.

Ordered interface must be implemented to return an order value less than -1. This is because the order value of NettyWriteResponseFilter is -1. We need to override the logic of returning the response body, and the custom GlobalFilter must be executed first than the NettyWriteResponseFilter.
After each restart of the gateway, the first request always fails to read a valid Body from the original ServerHttpRequest, and the exact phenomenon is that the NettyRoutingFilter call to ServerHttpRequest#getBody() gets an empty object, resulting in an empty pointer; strangely enough, it can be called normally from the second request onwards. I lowered the version of Spring Cloud Gateway to Finchley.SR3 and the version of Spring Boot to 2.0.8.RELEASE, the problem no longer occurs, and it is initially determined that it is a compatibility issue or a bug caused by the Spring Cloud Gateway version upgrade. BUG.

The most important thing is the use of ServerHttpResponse decorator ServerHttpResponseDecorator, mainly covering the part of the response body data buffer written, as to how to deal with other logic needs to consider themselves, here is just a simple demonstration. The general code logic is as follows.

ServerHttpResponse response = exchange.getResponse();
ServerHttpResponseDecorator responseDecorator = new ServerHttpResponseDecorator(response) {

            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                if (body instanceof Flux) {
                    Flux<? extends DataBuffer> flux = (Flux<? extends DataBuffer>) body;
                    return super.writeWith(flux.map(buffer -> {
                        // buffer is the buffer of the original response data
                        // Just return the buffer with the new response data after the following processing
                        return bufferFactory.wrap(...);
                    }));
                }
                return super.writeWith(body);
            }
        };
return chain.filter(exchange.mutate().response(responseDecorator).build());

Problems with oversized request or response body messages

Some enthusiastic users have told me that if the request message is too large or the response message is too large, the methods of modifying the request and response messages in the previous two sections will cause problems, so here is an attempt to reproduce the specific problems encountered. First, try to lengthen the request message.

Map<String, Object> json = new HashMap<>(8);
json.put("serialNumber", "请求流水号");
StringBuilder builder = new StringBuilder();
for (int i = 0; i < 1000; i++) {
    builder.append("doge");
}
String content = String.format("{\"name\": \"%s\"}", builder.toString());
json.put("payload", AesUtils.X.encrypt(content));
System.out.println(new ObjectMapper().writeValueAsString(json));

// The requested JSON message is as follows.
{
    "serialNumber": "请求流水号",
    "payload": "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"
}

Initiating a request with the request message above does present a problem

The main issues are.

After the request body packet data is subscribed to the Flux<DataBuffer> instance, the length of the byte array read is truncated. The length of the string in the original request message provided should be greater than 1000, and the conversion to a byte array should definitely be greater than 1000, but the above example only reads a byte array of length 673.
If the byte array is truncated, then the deserialization using Jackson indicates that the EOF identifier of the string is not read, causing the deserialization to fail.

Since we have encountered the problem, we will try to solve it. First step to locate what is the cause, intuition tells me: to turn on the DEBUG log to observe, if there is no clue may have to trace the source code.

After opening the DEBUG log level to make a request, found some suspicious log information.

2019-05-19 11:16:15.660 [reactor-http-nio-2] DEBUG reactor.ipc.netty.http.server.HttpServer - [id: 0xa9b527e5, L:/0:0:0:0:0:0:0:1:9090 - R:/0:0:0:0:0:0:0:1:58012] READ COMPLETE
2019-05-19 11:16:15.660 [reactor-http-nio-2] DEBUG reactor.ipc.netty.http.server.HttpServer - [id: 0xa9b527e5, L:/0:0:0:0:0:0:0:1:9090 ! R:/0:0:0:0:0:0:0:1:58012] INACTIVE
2019-05-19 11:16:15.660 [reactor-http-nio-3] DEBUG reactor.ipc.netty.http.server.HttpServer - [id: 0x5554e091, L:/0:0:0:0:0:0:0:1:9090 - R:/0:0:0:0:0:0:0:1:58013] READ: 1024B
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 50 4f 53 54 20 2f 6f 72 64 65 72 2f 6a 73 6f 6e |POST /order/json|
|00000010| 20 48 54 54 50 2f 31 2e 31 0d 0a 61 63 63 65 73 | HTTP/1.1..acces|
|00000020| 73 54 6f 6b 65 6e 3a 20 31 30 30 38 36 0d 0a 43 |sToken: 10086..C|
|00000030| 6f 6e 74 65 6e 74 2d 54 79 70 65 3a 20 61 70 70 |ontent-Type: app|
|00000040| 6c 69 63 61 74 69 6f 6e 2f 6a 73 6f 6e 0d 0a 55 |lication/json..U|
|00000050| 73 65 72 2d 41 67 65 6e 74 3a 20 50 6f 73 74 6d |ser-Agent: Postm|
|00000060| 61 6e 52 75 6e 74 69 6d 65 2f 37 2e 31 33 2e 30 |anRuntime/7.13.0|
|00000070| 0d 0a 41 63 63 65 70 74 3a 20 2a 2f 2a 0d 0a 43 |..Accept: */*..C|
|00000080| 61 63 68 65 2d 43 6f 6e 74 72 6f 6c 3a 20 6e 6f |ache-Control: no|
|00000090| 2d 63 61 63 68 65 0d 0a 50 6f 73 74 6d 61 6e 2d |-cache..Postman-|
|000000a0| 54 6f 6b 65 6e 3a 20 31 31 32 30 38 64 35 39 2d |Token: 11208d59-|
|000000b0| 65 61 34 61 2d 34 62 39 63 2d 61 30 33 39 2d 30 |ea4a-4b9c-a039-0|
|000000c0| 30 65 36 64 38 61 30 65 33 65 66 0d 0a 48 6f 73 |0e6d8a0e3ef..Hos|
|000000d0| 74 3a 20 6c 6f 63 61 6c 68 6f 73 74 3a 39 30 39 |t: localhost:909|
|000000e0| 30 0d 0a 63 6f 6f 6b 69 65 3a 20 63 75 73 74 6f |0..cookie: custo|
|000000f0| 6d 43 6f 6f 6b 69 65 4e 61 6d 65 3d 63 75 73 74 |mCookieName=cust|
|00000100| 6f 6d 43 6f 6f 6b 69 65 56 61 6c 75 65 0d 0a 61 |omCookieValue..a|
|00000110| 63 63 65 70 74 2d 65 6e 63 6f 64 69 6e 67 3a 20 |ccept-encoding: |
|00000120| 67 7a 69 70 2c 20 64 65 66 6c 61 74 65 0d 0a 63 |gzip, deflate..c|
|00000130| 6f 6e 74 65 6e 74 2d 6c 65 6e 67 74 68 3a 20 35 |ontent-length: 5|
|00000140| 34 31 36 0d 0a 43 6f 6e 6e 65 63 74 69 6f 6e 3a |416..Connection:|
|00000150| 20 6b 65 65 70 2d 61 6c 69 76 65 0d 0a 0d 0a 7b | keep-alive....{|
|00000160| 0a 20 20 20 20 22 73 65 72 69 61 6c 4e 75 6d 62 |.    "serialNumb|
|00000170| 65 72 22 3a 20 22 e8 af b7 e6 b1 82 e6 b5 81 e6 |er": "..........|
|00000180| b0 b4 e5 8f b7 22 2c 0a 20 20 20 20 22 70 61 79 |.....",.    "pay|
|00000190| 6c 6f 61 64 22 3a 20 22 30 44 63 66 32 70 6c 46 |load": "0Dcf2plF|
|000001a0| 70 45 53 70 72 4b 6a 6b 64 71 4e 48 4d 38 6a 6a |pESprKjkdqNHM8jj|
|000001b0| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
|000001c0| 71 76 2f 49 34 79 41 4b 35 48 65 31 31 75 53 35 |qv/I4yAK5He11uS5|
|000001d0| 64 76 36 6d 67 61 72 2f 79 4f 4d 67 43 75 52 33 |dv6mgar/yOMgCuR3|
|000001e0| 74 64 62 6b 75 58 62 2b 70 6f 47 71 2f 38 6a 6a |tdbkuXb+poGq/8jj|
|000001f0| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
|00000200| 71 76 2f 49 34 79 41 4b 35 48 65 31 31 75 53 35 |qv/I4yAK5He11uS5|
|00000210| 64 76 36 6d 67 61 72 2f 79 4f 4d 67 43 75 52 33 |dv6mgar/yOMgCuR3|
|00000220| 74 64 62 6b 75 58 62 2b 70 6f 47 71 2f 38 6a 6a |tdbkuXb+poGq/8jj|
|00000230| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
|00000240| 71 76 2f 49 34 79 41 4b 35 48 65 31 31 75 53 35 |qv/I4yAK5He11uS5|
|00000250| 64 76 36 6d 67 61 72 2f 79 4f 4d 67 43 75 52 33 |dv6mgar/yOMgCuR3|
|00000260| 74 64 62 6b 75 58 62 2b 70 6f 47 71 2f 38 6a 6a |tdbkuXb+poGq/8jj|
|00000270| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
|00000280| 71 76 2f 49 34 79 41 4b 35 48 65 31 31 75 53 35 |qv/I4yAK5He11uS5|
|00000290| 64 76 36 6d 67 61 72 2f 79 4f 4d 67 43 75 52 33 |dv6mgar/yOMgCuR3|
|000002a0| 74 64 62 6b 75 58 62 2b 70 6f 47 71 2f 38 6a 6a |tdbkuXb+poGq/8jj|
|000002b0| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
|000002c0| 71 76 2f 49 34 79 41 4b 35 48 65 31 31 75 53 35 |qv/I4yAK5He11uS5|
|000002d0| 64 76 36 6d 67 61 72 2f 79 4f 4d 67 43 75 52 33 |dv6mgar/yOMgCuR3|
|000002e0| 74 64 62 6b 75 58 62 2b 70 6f 47 71 2f 38 6a 6a |tdbkuXb+poGq/8jj|
|000002f0| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
|00000300| 71 76 2f 49 34 79 41 4b 35 48 65 31 31 75 53 35 |qv/I4yAK5He11uS5|
|00000310| 64 76 36 6d 67 61 72 2f 79 4f 4d 67 43 75 52 33 |dv6mgar/yOMgCuR3|
|00000320| 74 64 62 6b 75 58 62 2b 70 6f 47 71 2f 38 6a 6a |tdbkuXb+poGq/8jj|
|00000330| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
|00000340| 71 76 2f 49 34 79 41 4b 35 48 65 31 31 75 53 35 |qv/I4yAK5He11uS5|
|00000350| 64 76 36 6d 67 61 72 2f 79 4f 4d 67 43 75 52 33 |dv6mgar/yOMgCuR3|
|00000360| 74 64 62 6b 75 58 62 2b 70 6f 47 71 2f 38 6a 6a |tdbkuXb+poGq/8jj|
|00000370| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
|00000380| 71 76 2f 49 34 79 41 4b 35 48 65 31 31 75 53 35 |qv/I4yAK5He11uS5|
|00000390| 64 76 36 6d 67 61 72 2f 79 4f 4d 67 43 75 52 33 |dv6mgar/yOMgCuR3|
|000003a0| 74 64 62 6b 75 58 62 2b 70 6f 47 71 2f 38 6a 6a |tdbkuXb+poGq/8jj|
|000003b0| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
|000003c0| 71 76 2f 49 34 79 41 4b 35 48 65 31 31 75 53 35 |qv/I4yAK5He11uS5|
|000003d0| 64 76 36 6d 67 61 72 2f 79 4f 4d 67 43 75 52 33 |dv6mgar/yOMgCuR3|
|000003e0| 74 64 62 6b 75 58 62 2b 70 6f 47 71 2f 38 6a 6a |tdbkuXb+poGq/8jj|
|000003f0| 49 41 72 6b 64 37 58 57 35 4c 6c 32 2f 71 61 42 |IArkd7XW5Ll2/qaB|
+--------+-------------------------------------------------+----------------+
2019-05-19 11:16:15.662 [reactor-http-nio-2] DEBUG reactor.ipc.netty.http.server.HttpServer - [id: 0xa9b527e5, L:/0:0:0:0:0:0:0:1:9090 ! R:/0:0:0:0:0:0:0:1:58012] UNREGISTERED
2019-05-19 11:16:15.665 [reactor-http-nio-3] DEBUG reactor.ipc.netty.http.server.HttpServerOperations - [id: 0x5554e091, L:/0:0:0:0:0:0:0:1:9090 - R:/0:0:0:0:0:0:0:1:58013] Increasing pending responses, now 1
2019-05-19 11:16:15.671 [reactor-http-nio-3] DEBUG reactor.ipc.netty.http.server.HttpServer - [id: 0x5554e091, L:/0:0:0:0:0:0:0:1:9090 - R:/0:0:0:0:0:0:0:1:58013] READ COMPLETE

Note the keyword READ: 1024B, here should be the underlying Reactor-Netty read the maximum length of the datagram limit, the printed datagram is just 1024B size, this should be the root cause of the request body is truncated; this problem will not only appear in the request body to obtain, but also in the response body to write . Since this is a common problem, there must be a corresponding Issue on the project Github, find a longer interaction gateway request size limit 1024B because netty default limit 1024,how to solve it?#581, from the answer, the official recommendation is to use ModifyRequestBodyGatewayFilterFactory and ModifyResponseBodyGatewayFilterFactory to complete the corresponding function. Here you can try to borrow the implementation of ModifyRequestBodyGatewayFilterFactory to modify the previous code, because the logic of the code is longer and more complex, the filter for decrypting the request body is split into a new class RequestEncryptionGlobalFilter, the filter for encrypting the response body filter is split into ResponseDecryptionGlobalFilter.

The code for RequestEncryptionGlobalFilter is as follows.

@Slf4j
@Component
public class RequestEncryptionGlobalFilter implements GlobalFilter, Ordered {

    @Autowired
    private ObjectMapper objectMapper;

    private final List<HttpMessageReader<?>> messageReaders = HandlerStrategies.withDefaults().messageReaders();

    @Override
    public int getOrder() {
        return -2;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        return processRequest(exchange, chain);
    }

    private Mono<Void> processRequest(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerRequest serverRequest = new DefaultServerRequest(exchange, messageReaders);
        DataBufferFactory bufferFactory = exchange.getResponse().bufferFactory();
        Mono<String> rawBody = serverRequest.bodyToMono(String.class).map(s -> s);
        BodyInserter<Mono<String>, ReactiveHttpOutputMessage> bodyInserter = BodyInserters.fromPublisher(rawBody, String.class);
        HttpHeaders tempHeaders = new HttpHeaders();
        tempHeaders.putAll(exchange.getRequest().getHeaders());
        tempHeaders.remove(HttpHeaders.CONTENT_LENGTH);
        CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange, tempHeaders);
        return bodyInserter.insert(outputMessage, new BodyInserterContext()).then(Mono.defer(() -> {
            Flux<DataBuffer> body = outputMessage.getBody();
            DataBufferHolder holder = new DataBufferHolder();
            body.subscribe(dataBuffer -> {
                int len = dataBuffer.readableByteCount();
                holder.length = len;
                byte[] bytes = new byte[len];
                dataBuffer.read(bytes);
                DataBufferUtils.release(dataBuffer);
                String text = new String(bytes, StandardCharsets.UTF_8);
                JsonNode jsonNode = readNode(text);
                JsonNode payload = jsonNode.get("payload");
                String payloadText = payload.asText();
                byte[] content = AesUtils.X.decrypt(payloadText);
                String requestBody = new String(content, StandardCharsets.UTF_8);
                log.info("Modify request body payload,before:{},after:{}", payloadText, requestBody);
                rewritePayloadNode(requestBody, jsonNode);
                DataBuffer data = bufferFactory.allocateBuffer();
                data.write(jsonNode.toString().getBytes(StandardCharsets.UTF_8));
                holder.dataBuffer = data;
            });
            ServerHttpRequestDecorator requestDecorator = new ServerHttpRequestDecorator(exchange.getRequest()) {

                @Override
                public HttpHeaders getHeaders() {
                    long contentLength = tempHeaders.getContentLength();
                    HttpHeaders httpHeaders = new HttpHeaders();
                    httpHeaders.putAll(super.getHeaders());
                    if (contentLength > 0) {
                        httpHeaders.setContentLength(contentLength);
                    } else {
                        httpHeaders.set(HttpHeaders.TRANSFER_ENCODING, "chunked");
                    }
                    return httpHeaders;
                }

                @Override
                public Flux<DataBuffer> getBody() {
                    return Flux.just(holder.dataBuffer);
                }
            };
            return chain.filter(exchange.mutate().request(requestDecorator).build());
        }));
    }

    private void rewritePayloadNode(String text, JsonNode root) {
        try {
            JsonNode node = objectMapper.readTree(text);
            ObjectNode objectNode = (ObjectNode) root;
            objectNode.set("payload", node);
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }

    private void setPayloadTextNode(String text, JsonNode root) {
        try {
            ObjectNode objectNode = (ObjectNode) root;
            objectNode.set("payload", new TextNode(text));
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }

    private JsonNode readNode(String in) {
        try {
            return objectMapper.readTree(in);
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }

    private class DataBufferHolder {

        DataBuffer dataBuffer;
        int length;
    }
}

The code of ResponseDecryptionGlobalFilter is as follows.

@Slf4j
@Component
public class ResponseDecryptionGlobalFilter implements GlobalFilter, Ordered {

    @Autowired
    private ObjectMapper objectMapper;

    @Override
    public int getOrder() {
        return NettyWriteResponseFilter.WRITE_RESPONSE_FILTER_ORDER - 1;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        return processResponse(exchange, chain);
    }

    private Mono<Void> processResponse(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpResponseDecorator responseDecorator = new ServerHttpResponseDecorator(exchange.getResponse()) {

            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                String originalResponseContentType = exchange.getAttribute(ORIGINAL_RESPONSE_CONTENT_TYPE_ATTR);
                HttpHeaders httpHeaders = new HttpHeaders();
                httpHeaders.add(HttpHeaders.CONTENT_TYPE, originalResponseContentType);
                ResponseAdapter responseAdapter = new ResponseAdapter(body, httpHeaders);
                DefaultClientResponse clientResponse = new DefaultClientResponse(responseAdapter, ExchangeStrategies.withDefaults());
                Mono<String> rawBody = clientResponse.bodyToMono(String.class).map(s -> s);
                BodyInserter<Mono<String>, ReactiveHttpOutputMessage> bodyInserter = BodyInserters.fromPublisher(rawBody, String.class);
                CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange, exchange.getResponse().getHeaders());
                return bodyInserter.insert(outputMessage, new BodyInserterContext())
                        .then(Mono.defer(() -> {
                            Flux<DataBuffer> messageBody = outputMessage.getBody();
                            Flux<DataBuffer> flux = messageBody.map(buffer -> {
                                CharBuffer charBuffer = StandardCharsets.UTF_8.decode(buffer.asByteBuffer());
                                DataBufferUtils.release(buffer);
                                JsonNode jsonNode = readNode(charBuffer.toString());
                                JsonNode payload = jsonNode.get("payload");
                                String text = payload.toString();
                                String content = AesUtils.X.encrypt(text);
                                log.info("修改响应体payload,修改前:{},修改后:{}", text, content);
                                setPayloadTextNode(content, jsonNode);
                                return getDelegate().bufferFactory().wrap(jsonNode.toString().getBytes(StandardCharsets.UTF_8));
                            });
                            HttpHeaders headers = getDelegate().getHeaders();
                            if (!headers.containsKey(HttpHeaders.TRANSFER_ENCODING)) {
                                flux = flux.doOnNext(data -> headers.setContentLength(data.readableByteCount()));
                            }
                            return getDelegate().writeWith(flux);
                        }));
            }
        };
        return chain.filter(exchange.mutate().response(responseDecorator).build());
    }

    private void setPayloadTextNode(String text, JsonNode root) {
        try {
            ObjectNode objectNode = (ObjectNode) root;
            objectNode.set("payload", new TextNode(text));
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }

    private JsonNode readNode(String in) {
        try {
            return objectMapper.readTree(in);
        } catch (Exception e) {
            throw new IllegalStateException(e);
        }
    }

    private class ResponseAdapter implements ClientHttpResponse {

        private final Flux<DataBuffer> flux;
        private final HttpHeaders headers;

        @SuppressWarnings("unchecked")
        private ResponseAdapter(Publisher<? extends DataBuffer> body, HttpHeaders headers) {
            this.headers = headers;
            if (body instanceof Flux) {
                flux = (Flux) body;
            } else {
                flux = ((Mono) body).flux();
            }
        }

        @Override
        public Flux<DataBuffer> getBody() {
            return flux;
        }

        @Override
        public HttpHeaders getHeaders() {
            return headers;
        }

        @Override
        public HttpStatus getStatusCode() {
            return null;
        }

        @Override
        public int getRawStatusCode() {
            return 0;
        }

        @Override
        public MultiValueMap<String, ResponseCookie> getCookies() {
            return null;
        }
    }
}

Simulation request.

POST /order/json HTTP/1.1
Host: localhost:9090
accessToken: 10086
Content-Type: application/json
User-Agent: PostmanRuntime/7.13.0
Accept: */*
Cache-Control: no-cache
Postman-Token: 3a830202-f3d1-450e-839f-ae8f3b88bced,b229feb1-7c8b-4d25-a039-09345f3fe8f0
Host: localhost:9090
cookie: customCookieName=customCookieValue
accept-encoding: gzip, deflate
content-length: 5416
Connection: keep-alive
cache-control: no-cache

{
    "serialNumber": "请求流水号",
    "payload": "0Dcf2plFpESprKjkdqNHM8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/8jjIArkd7XW5Ll2/qaBqv/I4yAK5He11uS5dv6mgar/yOMgCuR3tdbkuXb+poGq/zyJ4ipyLGvo5LX87d9oDAs="
}

// response
{"serialNumber":"请求流水号","userId":null,"payload":"7S2VqLu4J6LdW0As50JgZ0eFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+DkeFFoe2FbWytaYdpr2HPg5HhRaHthW1srWmHaa9hz4OR4UWh7YVtbK1ph2mvYc+Dm8rTVHylECORYnLNgnfWx0ENJ9a6E+abYhyFJ9zSIda"}

completely solved the previous request or response message truncation problem, I found a lot of blog posts are (copy) change the code logic when reading DataBuffer instance, in fact, that logic is not relevant, you can try to use BufferedReader based on line reading and then use StringBuilder bearer, or as in this article directly read as byte arrays and so on, because the underlying reason is the underlying Reactor-Netty data block read size limit to get the DataBuffer instance inside the data is incomplete, the solution is to refer to the Spring Cloud Gateway itself to provide the basic class library for transformation (temporarily not found a portal to adjust the configuration of Reactor-Netty), and it is not very difficult.

Summary

I just came across a requirement to do the encryption and decryption of the gateway including the request and response body modifications, so here by the way, I combed through some of the Spring Cloud Gateway content involved in this area, stepped on the pits and filled them in by the way. The next step is to try to modify the available components to achieve custom logic, including Hystrix, Eureka and Ribbon based load balancing, flow limiting, etc.

Reference https://www.throwx.cn/2019/05/18/spring-cloud-gateway-modify-request-response/

Table of Contents

Prerequisites

Understanding ServerWebExchange

ServerWebExchange Interface

ServerHttpRequest interface

ServerHttpResponse interface

ServerWebExchangeUtils and Context Properties

Modify request body

Modify response body

Problems with oversized request or response body messages

Summary