Webflux，如何拦截请求并添加新标头

Question

使用Webflux过滤器，我试图拦截请求并检查请求是否来自某些URI然后添加一个新的Authorization标头

过滤器代码简单明了

@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class AuthorizationFilter implements WebFilter {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {

        return chain.filter(Optional.of(exchange)
                .filter(serverWebExchange -> serverWebExchange.getRequest().getURI().getPath().endsWith("/callback"))
                .map(serverWebExchange -> addNewHeader(serverWebExchange))
                .orElse(exchange));
    }

    private ServerWebExchange addNewHeader(ServerWebExchange serverWebExchange) {

        String authHeader=serverWebExchange.getRequest().getQueryParams().get("state").get(0);

        if (authHeader == null) {
            throw new BadRequestException("State not complete (access_token missing) for //callback");
        }

        try {
            serverWebExchange.getRequest().getHeaders().setBearerAuth(authHeader);
        }catch (Throwable t){
            t.printStackTrace();
        }

        return serverWebExchange;
    }
}

但是会抛出异常

java.lang.UnsupportedOperationException
    at org.springframework.http.ReadOnlyHttpHeaders.set(ReadOnlyHttpHeaders.java:99)
    at org.springframework.http.HttpHeaders.setBearerAuth(HttpHeaders.java:774)

标题映射似乎是只读的。我怎样才能克服这个问题并添加新的标题？

Answer 1

您可以使用它们的方法来改变 theServerWebExchange和 its ServerHttpRequest，这些mutate()方法为它们中的每一个都返回一个“Builder”。

示例 Java：

@Component
public class AuthorizationFilter implements WebFilter {
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
        ServerHttpRequest mutatedRequest = exchange.getRequest().mutate().header(HttpHeaders.AUTHORIZATION, "Bearer " + authHeader).build();
        ServerWebExchange mutatedExchange = exchange.mutate().request(mutatedRequest).build();
        return chain.filter(mutatedExchange);
    }
}

Kotlin 示例：

@Component
class AuthorizationFilter : WebFilter {
    override fun filter(exchange: ServerWebExchange, chain: WebFilterChain): Mono<Void> {
        val mutatedRequest = exchange.request.mutate().header(HttpHeaders.AUTHORIZATION, "Bearer $authHeader").build()
        val mutatedExchange = exchange.mutate().request(mutatedRequest).build()
        return chain.filter(mutatedExchange)
    }
}