Spring Cloud Gateway 注入头答案

【问题标题】：Spring Cloud Gateway inject headerSpring Cloud Gateway 注入头
【发布时间】：2018-09-25 11:40:16
【问题描述】：

在 GatewayFilter 中，我尝试将标头注入到请求中，如下所示。

@Override public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) { //DO SOME AUTHORIZATION OPERATIONS String jwt = "xxxxx" exchange.getRequest().getHeaders().add("headerkey", jwt); return chain.filter(exchange); }

但我收到以下错误：

java.lang.UnsupportedOperationException: null
at java.util.Collections$UnmodifiableMap.computeIfAbsent(Collections.java:1535) ~[na:1.8.0_111]
at org.springframework.http.HttpHeaders.add(HttpHeaders.java:1425) ~[spring-web-5.0.5.RELEASE.jar:5.0.5.RELEASE]
at com.trimble.sample.springcloudgateway.filter.AuthGatewayFilter.filter(AuthGatewayFilter.java:30) ~[classes/:na]
at org.springframework.cloud.gateway.filter.OrderedGatewayFilter.filter(OrderedGatewayFilter.java:44) ~[spring-cloud-gateway-core-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT]
at org.springframework.cloud.gateway.handler.FilteringWebHandler$DefaultGatewayFilterChain.filter(FilteringWebHandler.java:103) ~[spring-cloud-gateway-core-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT]
at org.springframework.cloud.gateway.filter.NettyWriteResponseFilter.filter(NettyWriteResponseFilter.java:62) ~[spring-cloud-gateway-core-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT]
at org.springframework.cloud.gateway.handler.FilteringWebHandler$GatewayFilterAdapter.filter(FilteringWebHandler.java:121) ~[spring-cloud-gateway-core-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT]
at org.springframework.cloud.gateway.filter.OrderedGatewayFilter.filter(OrderedGatewayFilter.java:44) ~[spring-cloud-gateway-core-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT]
at org.springframework.cloud.gateway.handler.FilteringWebHandler$DefaultGatewayFilterChain.filter(FilteringWebHandler.java:103) ~[spring-cloud-gateway-core-2.0.0.BUILD-SNAPSHOT.jar:2.0.0.BUILD-SNAPSHOT]

【问题讨论】：

你必须在请求上调用 mutate，然后在交换上调用 mutate
调用mutate方法如下： ServerHttpRequest request = exchange.getRequest() .mutate() .header("headerkey", jwt) .build(); exchange.mutate().request(request).build();返回链。过滤器（交换）；但是，标头不会注入到后端 api。我做错了吗？
我没有足够的信息可以说

标签： spring-cloud spring-cloud-gateway

【解决方案1】：

以下代码有效：

ServerHttpRequest request = exchange.getRequest()
                .mutate()
                .header("x-jwt-assertion", jwt)
                .build();
ServerWebExchange exchange1 = exchange.mutate().request(request).build();
            return chain.filter(exchange1);

【讨论】：

【解决方案2】：

你可以看看

org.springframework.cloud.gateway.filter.factory.*GatewayFilterFactory

有许多有用的网关过滤器实现。

对于你的问题，

org.springframework.cloud.gateway.filter.factory.AddRequestHeaderGatewayFilterFactory

有一个标准的实现。

public class AddRequestHeaderGatewayFilterFactory extends AbstractNameValueGatewayFilterFactory {

    @Override
    public GatewayFilter apply(NameValueConfig config) {
        return (exchange, chain) -> {
            ServerHttpRequest request = exchange.getRequest().mutate()
                    .header(config.getName(), config.getValue())
                    .build();

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

【讨论】：