今天爱分享给大家带来SpringCloud Gateway自定义filter获取body中的数据为空【解决办法】，希望能够帮助到大家。
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 @Slf4j 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 formatStr(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，大家可以按需所选