SpringCloud-gateway全局GlobalFilter获取post的请求参数

墨蓝 2022-05-13 15:22 733阅读 0赞

gateway里面可以自定义普通filter，也可以创建自定义的GlobalFilter。

GlobalFilter实际上还是比较常用的，譬如可以在GlobalFilter里做日志处理、认证鉴权等，这里就涉及一个获取到请求参数的问题。

用户发起Get、Post请求，经过网关gateway，gateway的GlobalFilter进行拦截——获取参数——处理并包装——转到下一级，我们就来看看该怎么获取请求的参数。

<parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.0.6.RELEASE</version>
            <relativePath/> 
        </parent>
    
        <properties>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <java.version>1.8</java.version>
            <spring-cloud.version>Finchley.SR1</spring-cloud.version>
        </properties>

### Get请求 ###

/**
     * @author wuweifeng wrote on 2018/10/24.
     */
    @Component
    public class AuthSignFilter implements GlobalFilter, Ordered {
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            String token = exchange.getRequest().getQueryParams().getFirst("authToken");
            if (token == null || token.isEmpty()) {
                exchange.getResponse().setStatusCode(HttpStatus.UNAUTHORIZED);
                return exchange.getResponse().setComplete();
            }
            return chain.filter(exchange);
    
        }
    
        @Override
        public int getOrder() {
            return 0;
        }
    }

这里定义了一个GlobalFilter，如果是Get请求，就可以通过getQueryParams().getFirst("你的key")的方式来获取。

![70][]

![70 1][]

可以看到已经获取到了Get请求的参数，如果有多个请求参数，就可以通过遍历exchange.getRequest().getQueryParams()来获取。

![70 2][]

### Post请求 ###

post请求的传参获取相对比较麻烦一些，gateway采用了webflux的方式来封装的请求体。

我们知道post常用的两种传参content-type是application/x-www-form-urlencoded和application/json，这两种方式还是有区别的。

下面来看一下获取Post请求体的方法，关于webflux获取内容的教程请看[上一篇][Link 1]。

package com.example.gateway.filter;
    
    import io.netty.buffer.ByteBufAllocator;
    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.core.io.buffer.NettyDataBufferFactory;
    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;
    
    import java.net.URI;
    import java.nio.CharBuffer;
    import java.nio.charset.StandardCharsets;
    import java.util.Map;
    import java.util.concurrent.atomic.AtomicReference;
    
    /**
     * @author wuweifeng wrote on 2018/10/24.
     */
    @Component
    public class AuthSignFilter implements GlobalFilter, Ordered {
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            ServerHttpRequest serverHttpRequest = exchange.getRequest();
            String method = serverHttpRequest.getMethodValue();
            if ("POST".equals(method)) {
                //从请求里获取Post请求体
                String bodyStr = resolveBodyFromRequest(serverHttpRequest);
                //TODO 得到Post请求的请求参数后，做你想做的事
    
                //下面的将请求体再次封装写回到request里，传到下一级，否则，由于请求体已被消费，后续的服务将取不到值
                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;
                    }
                };
                //封装request，传给下一级
                return chain.filter(exchange.mutate().request(request).build());
            } else if ("GET".equals(method)) {
                Map requestQueryParams = serverHttpRequest.getQueryParams();
                //TODO 得到Get请求的请求参数后，做你想做的事
    
                return chain.filter(exchange);
            }
            return chain.filter(exchange);
        }
    
        /**
         * 从Flux<DataBuffer>中获取字符串的方法
         * @return 请求体
         */
        private String resolveBodyFromRequest(ServerHttpRequest serverHttpRequest) {
            //获取请求体
            Flux<DataBuffer> body = serverHttpRequest.getBody();
    
            AtomicReference<String> bodyRef = new AtomicReference<>();
            body.subscribe(buffer -> {
                CharBuffer charBuffer = StandardCharsets.UTF_8.decode(buffer.asByteBuffer());
                DataBufferUtils.release(buffer);
                bodyRef.set(charBuffer.toString());
            });
            //获取request body
            return bodyRef.get();
        }
    
        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;
        }
    
        @Override
        public int getOrder() {
            return 0;
        }
    }

这里有详细的获取Post请求体的方法，无论是application/x-www-form-urlencoded和application/json都可以通过上面的方式。

看结果：

![70 3][]

![70 4][]

下面是@RequestBody形式的

![70 5][]

![70 6][]

这是后端消费的服务代码

![70 7][]

也能正常接收@RequestBody请求并解析。

[70]: /images/20220504/f00f88dc482343db85b70f96e6a7a824.png
[70 1]: /images/20220504/b8da93a79afd4373b7645014fa52c0e5.png
[70 2]: /images/20220504/04c0c3b353e146939e806fb563ca572f.png
[Link 1]: https://blog.csdn.net/tianyaleixiaowu/article/details/83348100
[70 3]: /images/20220504/dda2e2c8e4d34bf092e75df1be566e35.png
[70 4]: /images/20220504/09f7ba2ac9cc43eeaa6f9cdcb832d250.png
[70 5]: /images/20220504/ec98089dd4ed4bc8a84e974d257ff331.png
[70 6]: /images/20220504/446aeacce58d471582cdc2bfcc1d8eb2.png
[70 7]: /images/20220504/1419e823100047479c3f23671efce11e.png