SpringCloud gateway request的body驗證或修改方式

Posted on 2021-07-17 by WalkonNet

SpringCloud gateway request的body驗證或修改

後續版本新增瞭以下過濾器

org.springframework.cloud.gateway.filter.headers.RemoveHopByHopHeadersFilter

默認會把以下頭部移除（暫不瞭解這做法的目的）

– connection

– keep-alive

– te

– transfer-encoding

– trailer

– proxy-authorization

– proxy-authenticate

– x-application-context

– upgrade

從而導致下面我們重寫getHeaders方法時添加的transfer-encoding頭部移除，導致無法解析body。

解決辦法：

在yml文件中配置自定義的頭部移除列表

spring:
  cloud:
      filter:
        remove-hop-by-hop:
          headers:
            - connection
            - keep-alive
            - te
            - trailer
            - proxy-authorization
            - proxy-authenticate
            - x-application-context
            - upgrade

源碼可見鏈接，且可實現動態路由配置：https://github.com/SingleTigger/SpringCloudGateway-Nacos-Demo

————原文————

往往業務中我們需要在網關對請求參數作修改操作（註意以下隻針對帶有body的請求），springcloud gateway中有提供一個

ModifyRequestBodyGatewayFilterFactory的filter，看瞭一下它的實現，需要指定輸入類型和輸出類型，比較局限。

我就參考它自己實現瞭一個攔截器

註意：上傳文件也帶有請求body，需特殊處理。

以下是主要代碼

 
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.cloud.gateway.support.BodyInserterContext;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpHeaders;
import org.springframework.http.codec.HttpMessageReader;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.BodyInserter;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.HandlerStrategies;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
 
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.BiFunction;
 
/**
 * @author chenws
 * @date 2019/12/12 09:33:53
 */
@Component
public class CModifyRequestBodyGatewayFilterFactory extends AbstractGatewayFilterFactory { 
    private final List<HttpMessageReader<?>> messageReaders; 
    public CModifyRequestBodyGatewayFilterFactory() {
        this.messageReaders = HandlerStrategies.withDefaults().messageReaders();
    }
 
    @Override
    @SuppressWarnings("unchecked")
    public GatewayFilter apply(Object config) {
        return (exchange, chain) -> {
            ServerRequest serverRequest = ServerRequest.create(exchange,
                    this.messageReaders);
 
            Mono<String> modifiedBody = serverRequest.bodyToMono(String.class)
                    .flatMap(originalBody -> modifyBody()
                            .apply(exchange,Mono.just(originalBody)));
 
            BodyInserter bodyInserter = BodyInserters.fromPublisher(modifiedBody,
                    String.class);
            HttpHeaders headers = new HttpHeaders();
            headers.putAll(exchange.getRequest().getHeaders());
            headers.remove(HttpHeaders.CONTENT_LENGTH);
 
            CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange,
                    headers);
            return bodyInserter.insert(outputMessage, new BodyInserterContext())
                    .then(Mono.defer(() -> {
                        ServerHttpRequest decorator = decorate(exchange, headers,
                                outputMessage);
                        return chain.filter(exchange.mutate().request(decorator).build());
                    })); 
        };
    }
 
    /**
     * 修改body
     * @return apply 返回Mono<String>，數據是修改後的body
     */
    private BiFunction<ServerWebExchange,Mono<String>,Mono<String>> modifyBody(){
        return (exchange,json)-> {
            AtomicReference<String> result = new AtomicReference<>();
            json.subscribe(
                    value -> {
                        //value 即為請求body，在此處修改
                        result.set(value);
                        System.out.println(result.get());
                    },
                    Throwable::printStackTrace
            );
            return Mono.just(result.get());
        };
    }
 
    private ServerHttpRequestDecorator decorate(ServerWebExchange exchange, HttpHeaders headers,
                                        CachedBodyOutputMessage outputMessage) {
        return new ServerHttpRequestDecorator(exchange.getRequest()) {
            @Override
            public HttpHeaders getHeaders() {
                long contentLength = headers.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 outputMessage.getBody();
            }
        };
    }
}

SpringCloud Gateway獲取post請求體(request body)不完整解決方案

Spring Cloud Gateway做為網關服務，通過gateway進行請求轉發，在請求到達後端服務前我們可以通過filter進行一些預處理如：請求的合法性，商戶驗證等。

如我們在請求體中添加商戶ID（merId）和商戶KEY（merkey），通過此來驗證請求的合法性。但是如果我們請求內容太長如轉為base64的文件存儲請求。此時我們在filter獲取body內容就會被截取(太長的 Body 會被截斷)。目前網上也沒有好的解決方式。

springboot及Cloud版本如下；

	版本
springboot	2.0.8.RELEASE
springcloud	Finchley.SR2

這裡提供一種解決方式，相關代碼如下：

1.Requestfilter

我們采用Gateway網關的Gobalfilter，建立我們的第一個過濾器過濾所有請求。

1).通過Spring 5 的 WebFlux我們使用bodyToMono方法把響應內容轉換成類 String的對象，最終得到的結果是 Mono對象

2).bodyToMono方法我們可以拿到完整的body內容，並返回String。

3).我們生成唯一的token（通過UUID），並將token放入請求的header中。

4).將獲取到的完整body內容，存放到redis中。

@Component
public class RequestFilter implements GlobalFilter, Ordered {
	@Autowired
	private RedisClientTemplate redisClientTemplate;
	@Override
	public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
		DefaultServerRequest req = new DefaultServerRequest( exchange );
		String token = UUID.randomUUID().toString();
		//向headers中放入token信息
		ServerHttpRequest serverHttpRequest =exchange.getRequest().mutate().header("token", token)
				.build();
		//將現在的request變成change對象
		ServerWebExchange build = exchange.mutate().request( serverHttpRequest ).build();
		return req.bodyToMono( String.class ).map( str -> {
			redisClientTemplate.setObjex( "microservice:gateway:".concat( token ), 180, str );
			MySlf4j.textInfo( "請求參數:{0}", str );
			return str;
		} ).then( chain.filter( build ) );
	}
	@Override
	public int getOrder() {
		return 0;
	}
}

2.MerchantAuthFilter

建立商戶認證過濾器，相關代碼如下：

1).獲取存儲在headers中的token。

2).通過token獲取我們存儲在redis中的body內容(WebFlux 中不能使用阻塞的操作，目前想到的是通過這種方式實現)。

3).獲取到完整的body內容後我們就可以進行相應的商戶認證操作。

4).認證通過，將信息重新寫入，不通過則返回異常信息。

@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
	/** 驗證商戶是否有權限訪問 */
	ServerHttpRequest serverHttpRequest = exchange.getRequest();
	String token = serverHttpRequest.getHeaders().get( "token" ).get( 0 );
       String bodyStr = (String) redisClientTemplate.getObj("microservice:gateway:".concat(token));
	BaseReqVo baseReqVo = JsonUtil.fromJson( bodyStr, BaseReqVo.class );
	try {
		// 商戶認證
		BaseRespVo<?> baseRespVo = merchantAuthService.checkMerchantAuth( baseReqVo );
		if (MicroserviceConstantParamUtils.RESULT_CODE_SUCC.equals( baseRespVo.getCode() )) {
               // 若驗證成功，將信息重新寫入避免request信息消費後後續無法從request獲取信息的問題
               URI uri = serverHttpRequest.getURI();
               ServerHttpRequest request = serverHttpRequest.mutate().uri(uri).build();
               DataBuffer bodyDataBuffer = stringBuffer(bodyStr);
               Flux<DataBuffer> bodyFlux = Flux.just(bodyDataBuffer);
               request = new ServerHttpRequestDecorator(request) {
                   @Override
                   public Flux<DataBuffer> getBody() {
                       return bodyFlux;
                   }
               };
			// 封裝request，傳給下一級
               return chain.filter(exchange.mutate().request(request).build());
		} else {
			// 若驗證不成功，返回提示信息
			return gatewayResponse( baseRespVo.getCode(), baseRespVo.getMessage(), exchange );
		}
	} catch (MicroserviceServiceException ex) {
		// 若驗證不成功，返回提示信息
		MySlf4j.textError( "商戶訪問權限驗證異常，異常代碼:{0},異常信息:{1}, 異常{2}", ex.getCode(), ex.getMessage(), ex );
		return gatewayResponse( ex.getCode(), ex.getMessage(), exchange );
	} catch (Exception ex) {
		MySlf4j.textError( "商戶訪問權限驗證服務異常:{0}", LogUtil.ExceptionToString( ex ) );
		return gatewayResponse( MicroserviceException.ERR_100000, "系統異常", exchange );
	} finally {
		redisClientTemplate.del( "microservice:gateway:".concat( token ) );
	}
}
/**數據流處理方法*/
private DataBuffer stringBuffer(String value) {
	byte[] bytes = value.getBytes( StandardCharsets.UTF_8 );
	NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory( ByteBufAllocator.DEFAULT );
	DataBuffer buffer = nettyDataBufferFactory.allocateBuffer( bytes.length );
	buffer.write( bytes );
	return buffer;
}
/**網關請求響應*/
private Mono<Void> gatewayResponse(String code, String message, ServerWebExchange exchange) {
	// 若驗證不成功，返回提示信息
	ServerHttpResponse response = exchange.getResponse();
	BaseRespVo<T> baseRespVo = ResponseUtils.responseMsg( code, message, null );
	byte[] bits = JsonUtil.toJson( baseRespVo ).getBytes( StandardCharsets.UTF_8 );
	DataBuffer buffer = response.bufferFactory().wrap( bits );
	response.setStatusCode( HttpStatus.UNAUTHORIZED );
	// 指定編碼，否則在瀏覽器中會中文亂碼
	response.getHeaders().add( "Content-Type", "text/plain;charset=UTF-8" );
	return response.writeWith( Mono.just( buffer ) );
}
@Override
public int getOrder() {
	return 1;
}

另外我們還可以通過GlobalFilter實現請求過濾，OAUTH授權，相關代碼如下：

請求方式驗證過濾器（RequestAuthFilter）：

@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
 ServerHttpRequest serverHttpRequest = exchange.getRequest();
 String method = serverHttpRequest.getMethodValue();
 if (!"POST".equals(method)) {
  ServerHttpResponse response = exchange.getResponse();
  BaseRespVo<T> baseRespVo = ResponseUtils.responseMsg(MicroserviceException.ERR_100008, "非法請求", null);
  byte[] bits = JsonUtil.toJson(baseRespVo).getBytes(StandardCharsets.UTF_8);
  DataBuffer buffer = response.bufferFactory().wrap(bits);
  response.setStatusCode(HttpStatus.UNAUTHORIZED);
  //指定編碼，否則在瀏覽器中會中文亂碼
  response.getHeaders().add("Content-Type", "text/plain;charset=UTF-8");
  return response.writeWith(Mono.just(buffer));
 }
 return chain.filter(exchange);
 }

OAUTH授權過濾器（OAuthSignatureFilter）：

/**授權訪問用戶名*/
@Value("${spring.security.user.name}")
private String securityUserName;
/**授權訪問密碼*/
@Value("${spring.security.user.password}")
private String securityUserPassword;
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
 /**oauth授權*/
 String auth = securityUserName.concat(":").concat(securityUserPassword);
 String encodedAuth = new sun.misc.BASE64Encoder().encode(auth.getBytes(Charset.forName("US-ASCII")));
 String authHeader = "Basic " + encodedAuth;
 //向headers中放授權信息
 ServerHttpRequest serverHttpRequest = exchange.getRequest().mutate().header("Authorization", authHeader)
   .build();
 //將現在的request變成change對象
 ServerWebExchange build = exchange.mutate().request(serverHttpRequest).build();
 return chain.filter(build);
}

以上為個人經驗，希望能給大傢一個參考，也希望大傢多多支持WalkonNet。

SpringCloud gateway request的body驗證或修改方式