SpringCloud Gateway自定义filter获取body中的数据为空的问题

SpringCloud Gateway自定义filter获取body中的数据为空的问题

最近在使用SpringCloud Gateway进行网关的开发，我使用的版本是：SpringBoot的2.3.4.RELEASE+SpringCloud的Hoxton.SR8，在自定义过滤器时需要获取ServerHttpRequest中body的数据，发现一直无法获取到数据，经过各种百度、谷歌，再加上自己的实践，终于找到解决方案：

1、首先创建一个全局过滤器把body中的数据缓存起来

package com.cloudpath.gateway.portal.filter;

import lombok.extern.slf4j.Slf4j;

import org.springframework.cloud.gateway.filter.GatewayFilterChain;

import org.springframework.cloud.gateway.filter.GlobalFilter;

import org.springframework.core.Ordered;

import org.springframework.core.io.buffer.DataBuffer;

import org.springframework.core.io.buffer.DataBufferUtils;

import org.springframework.http.server.reactive.ServerHttpRequest;

import org.springframework.http.server.reactive.ServerHttpRequestDecorator;

import org.springframework.stereotype.Component;

import org.springframework.web.server.ServerWebExchange;

import reactor.core.publisher.Flux;

import reactor.core.publisher.Mono;

/**

* @author mazhen

* @className CacheBodyGlobalFilter

* @Description 把body中的数据缓存起来

* @date 2020/10/28 18:02

*/

@Slf4j

@Component

public class CacheBodyGlobalFilter implements Ordered, GlobalFilter {

// public static final String CACHE_REQUEST_BODY_OBJECT_KEY = "cachedRequestBodyObject";

@Override

public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) {

if (exchange.getRequest().getHeaders().getContentType() == null) {

return chain.filter(exchange);

} else {

return DataBufferUtils.join(exchange.getRequest().getBody())

.flatMap(dataBuffer -> {

DataBufferUtils.retain(dataBuffer);

Flux cachedFlux = Flux

.defer(() -> Flux.just(dataBuffer.slice(0, dataBuffer.readableByteCount())));

ServerHttpRequest mutatedRequest = new ServerHttpRequestDecorator(

exchange.getRequest()) {

@Override

public Flux getBody() {

return cachedFlux;

}

};

//exchange.getAttributes().put(CACHE_REQUEST_BODY_OBJECT_KEY, cachedFlux);

return chain.filter(exchange.mutate().request(mutatedRequest).build());

});

}

}

@Override

public int getOrder() {

return Ordered.HIGHEST_PRECEDENCE;

}

}

CacheBodyGlobalFilter这个全局过滤器的目的就是把原有的request请求中的body内容读出来，并且使用ServerHttpRequestDecorator这个请求装饰器对request进行包装，重写getBody方法，并把包装后的请求放到过滤器链中传递下去。这样后面的过滤器中再使用exchange.getRequest().getBody()来获取body时，实际上就是调用的重载后的getBody方法，获取的最先已经缓存了的body数据。这样就能够实现body的多次读取了。

值得一提的是，这个过滤器的order设置的是Ordered.HIGHEST_PRECEDENCE，即最高优先级的过滤器。优先级设置这么高的原因是某些系统内置的过滤器可能也会去读body，这样就会导致我们自定义过滤器中获取body的时候报body只能读取一次这样的错误如下:

java.lang.IllegalStateException: Only one connection receive subscriber allowed.

at reactor.ipc.netty.channel.FluxReceive.startReceiver(FluxReceive.java:279)

at reactor.ipc.netty.channel.FluxReceive.lambda$subscribe$2(FluxReceive.java:129)

at

所以，必须把CacheBodyGlobalFilter的优先级设到最高。

2、在自定义的过滤器中尝试获取body中的数据

package com.cloudpath.iam.gateway.customerfilter;

import com.cloudpath.iam.gateway.utils.FilterRequestResponseUtil;

import lombok.extern.slf4j.Slf4j;

import org.springframework.cloud.gateway.filter.GatewayFilter;

import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;

import org.springframework.core.io.buffer.DataBuffer;

import org.springframework.http.server.reactive.ServerHttpRequest;

import org.springframework.stereotype.Component;

import reactor.core.publisher.Flux;

import java.util.Arrays;

import java.util.List;

/**

* @author by mazhen

* @Classname TestGatewayFilterFactory

* @Description 自定义过滤器获取body中的数据

* @Date 2020/10/27 14:38

*/

@Component

@wafAqNvSlf4j

public class TestGatewayFilterFactory extends AbstractGatewayFilterFactory {

@Override

public List shortcutFieldOrder() {

return Arrays.asList("enabled");

}

public TestGatewayFilterFactory() {

super(Config.class);

log.info("Loaded TestGatewayFilterFactory");

}

@Override

public GatewayFilter apply(Config config) {

return (exchange, chain) -> {

if (!config.isEnabled()) {

return chain.filter(exchange);

}

if (null != exchange) {

ServerHttpRequest httpRequest = exchange.getRequest();

try {

Flux dataBufferFlux = httpRequest.getBody();

//获取body中的数据

String body = FilterRequestResponseUtil.resolveBodyFromRequest(dataBufferFlux);

log.info("body:{}",body);

} catch (Exception e) {

log.error("异常:",e);

return chain.filter(exchange);

}

}

return chain.filter(exchange);

};

}

public static class Config {

/**

* 控制是否开启统计

*/

private boolean enabled;

public Config() {

}

public boolean isEnabled() {

return enabled;

}

public void setEnabled(boolean enabled) {

this.enabled = enabled;

}

}

}

3、解析body的工具类

package com.cloudpath.iam.gateway.utils;

import org.springframework.core.io.buffer.DataBuffer;

import org.springframework.core.io.buffer.DataBufferUtils;

import reactor.core.publisher.Flux;

import java.nio.CharBuffer;

import java.nio.charset.StandardCharsets;

import java.util.concurrent.atomic.AtomicReference;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

/**

* @author mazhen

* @className FilterHeadersUtil

* @Description 过滤器请求/响应工具类

* @date 2020/10/29 9:31

*/

public final class FilterRequestResponseUtil {

/**

* spring cloud gateway 获取post请求的body体

* @param body

* @return

*/

public static String resolveBodyFromRequest( Flux body){

AtomicReference bodyRef = new AtomicReference<>();

// 缓存读取的request body信息

body.subscribe(dataBuffer -> {

CharBuffer charBuffer = StandardCharsets.UTF_8.decode(dataBuffer.asByteBuffer());

DataBufferUtils.release(dataBuffer);

bodyRef.set(charBuffer.toString());

});

//获取request body

return bodyRef.get();

}

/**

* 读取body内容

* @param body

* @return

*/

public static String resolveBodyFromRequest2( Flux body){

StringBuilder sb = new StringBuilder();

body.subscribe(buffer -> {

byte[] bytes = new byte[buffer.readableByteCount()];

buffer.read(bytes);

DataBufferUtils.release(buffer);

String bodyString = new String(bytes, StandardCharsets.UTF_8);

sb.append(bodyString);

});

return formatStr(sb.toString());

}

/**

* 去掉空格,换行和制表符

* @param str

* @return

*/

private static String formatStwafAqNvr(String str){

if (str != null && str.length() > 0) {

Pattern p = Pattern.compile("\\s*|\t|\r|\n");

Matcher m = p.matcher(str);

return m.replaceAll("");

}

return str;

}

}

解析body的内容，网上普遍是上面的两种方式,亲测resolveBodyFromRequest方法解析body中的数据，没有1024字节的限制。

ps：我传的参数有1万多字节。。。。。。。

大家可以按需所选。

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。